P - Poster Session Exhibit Hall 13:30 - 15:00
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P.1 Radio-biology - Biological Response
Building a Statistical Index on Nuclear Security Culture Awareness at a University MP Robinson, Purdue University
; NJ German*, Purdue University; JT Harris, Purdue University
Abstract: Cultural assessments of safety and security at nuclear facilities are fairly well established. However, in many publicly accessible settings that have radioactive materials, such as academic institutions, culture is not assessed or evaluated. This is important due to the increasing number of incidents and threats involving nuclear and radiological materials. Also, insider threats to these materials and associated facilities may pose the greatest risk. To assess nuclear security culture at a university with a variety of radioactive materials, a survey was deployed and completed by 3,336 students and personnel. The survey contained a total of 12 questions and was divided into three categories: general awareness, university specific awareness, and behavioral response awareness. Members were classified using a variety of demographics such as age, gender, ethnicity, nationality, work category, and degree. Responses were evaluated using a variety of statistical methods that indicated which of the demographics affected a survey taker's response. The results of the survey evaluation using a Chi-squared test showed that the demographic values chosen are dependent or related. The ANOVA regression for general awareness demonstrates that age, gender, nationality, and ethnicity have statistical significance in regards to the mean scores of survey responses. The university specific awareness ANOVA regression indicates that work status, nationality, and gender showed significant differences in the mean score of responses. The ANOVA regression for behavioral response awareness was only significant for age, degree, and gender in the mean score of responses. The results suggest that overall nuclear security cultural awareness is most influenced by age and gender.
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P.2 Risk Assessment
The Pseudo Pelger-Huet Cell, a Fast and Cheap Potential Biomarker for Radiation Dose: An Overview KE Reti*, Colorado State University
; TE Johnson, Colorado State University; JM Hayes, Colorado State University
Abstract: The Pelger-Huet anomaly was first described in 1928 by physician Karl Pelger as an anomalous neutrophil morphology. Neutrophils are a white blood cell that normally present segmented nuclei ranging between 3-7 segmentations. A Pelger-Huet anomaly is an abnormal neutrophil due to its hypo-segmented nucleus consisting of 2 segments that take on a dumbbell shape with a thin mitotic bridge connecting the two segments. Through a sequence of studies, the anomaly was identified as an inherited trait due to a mutation on the long arm of chromosome one that impacts structural components of the nucleus.
An increased prevalence of the morphology has been observed as radiation induced in acute dose victims of a criticality accident, as well as chronic dose victims from radium watch dial painting. This radiation induced morphology has been classified as a pseudo Pelger-Huet anomaly and is being assessed as a potential biomarker for radiation dose. Since the anomaly's increased prevalence was first observed in radiation exposure victims, it has been identified to have a correlated dose response in humans, bats, and wild boar. Current research is being conducted to further characterize the neutrophil anomaly to identify cellular mechanisms that led to the characteristic dumbbell shaped morphology.
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P.3 External Dosimetry
Research of Indications of Albedo Individual Neutron Dosimeters in the Fields of Mixed Gamma-Neutron Radiation of Various Origin PP Gantsovskiy*, State Research Center - Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency
; AG Tsovyanov, State Research Center - Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency; SM Shinkarev, State Research Center - Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency
Abstract: Albedo individual neutron dosimeters are often used in order to monitor the neutron doses of workers in the fields of mixed gamma-neutron radiation. However, the indications of those dosimeters might significantly differ from the actual neutron doses of workers. The energy dependence of the sensitivity of albedo dosimeters significantly differs from the energy dependence of the conversion coefficients of the transition from the flux density to the individual dose equivalent Hp(10), the operating value recommended for individual dosimetric monitoring. The purpose of this work is to determine the correction coefficients to apply to the indications of the neutron dosimeters in order to estimate an actual dose from neutron radiation to workers. The spectra of neutron radiation in the fields of mixed gamma-neutron radiation of various origins were measured at various workplaces of workers using a multispheric neutron spectrometer (Bonner spectrometer) DSN-01. The estimates of the effective dose were calculated based on the spectra measured. Those estimates were compared with the indications of the neutron dosimeters. Difference between the indication of neutron dosimeter and the estimate of the effective dose, calculated based on the spectra measured, significantly depends on the spectrum of the neutron radiation. At the nuclear power plants with power units of various types, an overestimation of the individual neutron dose estimate measured by the neutron dosimeters was by a factor of 5-10. In the case of exposure from neutron isotope sources when biological shield is used, which mitigates the spectrum of neutron radiation, such an overestimation is estimated to be in the range on average of 2-4 times. In the case of exposure from neutron isotope sources without biological shield an overestimation of the indications of individual albedo thermoluminescent neutron dosimeters was also observed due to the slowing down of neurons in the walls of working premises by a factor of about 2. The results presented above clearly show that in order to objectively estimate the neutron dose received by workers based on the indications of individual albedo thermoluminescent neutron dosimeters it is necessary to correct the indications of individual dosimeters, taking into account the actual neutron radiation spectra at specific workplaces.
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P.4 External Dosimetry
Evaluation of Individual Extremity Dose Using 3D Scanner and Monte Carlo Simulation HS Kim*, Korea Institute of Radiological and Medical Sciences
; Y Kim, Korea Institute of Radiological and Medical Sciences; WH Ha, Korea Institute of Radiological and Medical Sciences; S Park, Korea Institute of Radiological and Medical Sciences
Abstract: As the number of workers who directly handle high activity source with their hands has increased, reliable and fast evaluation of extremity dose has become more important. Evaluation of extremity dose is usually performed by radiation dosimeters, such as ring dosimeters and wrist dosimeters, or a very simplified computational phantom. These dosimeters, however, may be impractical to estimate the most exposed part of the hands. Also, the simple phantom may be insufficient to reflect complex shape and posture of human hands. This study proposes a method to evaluate the extremity dose while faithfully keeping the outmost shape and reflecting different hand postures. A handheld-type 3D scanner, which is a powerful tool to quickly obtain detailed contour information of an object, was adopted in this study. Hands in different postures were carefully captured, and the 3D data in mesh format were obtained. Then, the 3D data were imported to Geant4 Monte Carlo code in order to acquire dose distribution. The proposed method does not need additional process which could lead to not only time-consuming tasks but also distortion of the 3D model. We believe that this method provides a straightforward way to evaluate the individual extremity dose for different exposure situations.
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P.5 External Dosimetry
Practical Lessons for Transitioning to a New Dosimetry System MA Baca*, Mirion - DSD
Abstract: Mirion Dosimetry Services Division processes over 5 million dosimeters annually. Part of this business includes transitioning new clients to the Mirion system or transitioning existing clients to a new dosimeter type. These transitions are typically addressed on an individual client basis and come with their fair share of challenges, but a more pragmatic approach would be to supply these lessons learned on a larger scale.
Sharing this information can better equip any dosimetry program manager with some basic knowledge to assist with any badge transition plan, be it with Mirion or another service provider. Key considerations and examples are included to facilitate understanding, such as: 1-Importance of performance assessments, 2-Client on-boarding and training, 3-Understanding radiation fields and system needs, 4-Service considerations and logistics, 5-Typical transition timelines and regulatory considerations.
As with any relationship involving clients and vendors, the key to success is communication. Failing to understand the requirements (either by the vendor or the client) will certainly result in delays and cost-overages for any badge transition project. Routine discussions and understanding expectations at the start of a transition has shown to alleviate or mitigate many of the delays typically encountered.
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P.6 External Dosimetry
Establishment of Database for Retrospective Dose Estimation in Industrial Radiography Accidents Y Kim*, Korea Institute of Radiological and Medical Sciences
; HS Kim, Korea Institute of Radiological and Medical Sciences; WH Ha, Korea Institute of Radiological and Medical Sciences; S Jang, Korea Institute of Radiological and Medical Sciences
Abstract: Industrial radiography, which uses high activity radiation sources, is one of the most high-risk radiation practices. A frequent accident may occur when a worker handles equipment close to a radiation source while not wearing alarming dosimeters, so that the worker may be highly irradiated. In this case, Monte Carlo simulation can be used to estimate the dose of the worker retrospectively, based on the statements about the accident situation. Monte Carlo simulation is, however, too technical for a non-specialist to utilize to estimate the dose of an accident case. In the present study, we established a database by using Geant4 Monte Carlo simulation to estimate the dose of the worker for various accident cases in industrial radiography fields. We considered the accident situation that a cobalt-60 source is located on the floor near the worker. The database provides the dose conversion coefficients in terms of the source-to-worker distance, irradiated direction, and posture of the worker. To represent the worker, adult-male version of mesh-type reference computational phantom (MRCP), which has been recently developed by International Commission on Radiological Protection (ICRP), was used in the simulation. The result was represented in terms of wT-weighted dose per single decay (Sv s-1 Bq-1). The database can be utilized to estimate the total dose for each condition of source-to-worker distance, irradiated direction, and posture of the worker.
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P.7 External Dosimetry
Characterization of an Automated, All-Purpose Thermoluminescent Dosimeter Reader with Removable Planchets JH Thiesen, University of Michigan
; JR Kuchta*, University of Michigan; KD Pombier, University of Michigan; LK Chung, University of Michigan; RM Golduber, University of Michigan; JD Noey, University of Michigan; KJ Kearfott, University of Michigan
Abstract: The Rexon UL-320-FDR thermoluminescent dosimeter (TLD) reader is capable of automatically processing TLDs in powder, chip, rod, or disk form, using sets of removable bar-coded planchets. The planchets may be irradiated and annealed along with individual TLD samples, whose identities are preserved during the process. The UL-320 uses an infrared light sensor observing a black-body emissive coating on the back of the planchets to accurately and rapidly measure planchet temperature. This measurement system, having a nominal accuracy of + 2 oC and a 9 ms approximate response time, allows the user to study materials with heating rates varying between 0.8 and 10 oC s 1. Special software further enables complex heating cycles as long as 600 s. This work presents a careful examination of the performance of the UL-320-FDR. The effects of photomultiplier voltage on the dark current and reference light counts were measured, and longer term stability analyzed. An experiment to measure planchet glow for different time temperature profiles and planchet types was completed. A reader-based method for planchet cleaning, although not deemed essential, was developed. A set of 25 LiF:Mg,Ti TLD chips were calibrated to demonstrate the overall system performance. The effect of nitrogen, not essential for planchet heating, on performance was also examined.
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P.8 External Dosimetry
Preliminary Demonstration of a Method for Temporal Dosimetry using Passive, Integrating LiF:Mg,Ti Thermoluminescent Dosimeters JH Thiesen*, University of Michigan
; KJ Kearfott, University of Michigan
Abstract: Radiation dosimetry is traditionally conducted using integrating solid state materials such as optically stimulated luminescent dosimeters and thermoluminescent dosimeters (TLDs). Fading of signal with time at room temperature has been historically considered an undesirable property of such materials, but can be exploited to extract information about dose as a function of time during the dosimeter deployment period. With glow curve analysis, different signal peak areas corresponding to different trapping states may be extracted from TLDs. As these signals fade at unique rates characteristic of each trap type, dose as a function of time may be mathematically determined for as many time periods as different signal peaks are available. This work presents the performance of such a method for LiF:Mg,Ti (TLD-100), which involves deconvolution under conditions of hypothetical experimental error. The results of an experimental demonstration of the extraction of dose as a function of time for LiF:Mg,Ti dosimeters deployed over an 8 week period will be presented.
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P.9 External Dosimetry
The Circle Experiment: Consistency of Radiation Dose Delivery for a Dosimeter Calibration Facility RM Golduber, University of Michigan
; JR Kuchta, University of Michigan; RJ Champion*, University of Michigan; KJ Kearfott, University of Michigan
Abstract: Periodic validation of the dose delivered by a 137Cs source using a secondary or tertiary ion chamber is advisable because of the small possibility of source failures, such as reduced doses as a result of faulty relays which have been infrequently reported. The availability of a large number of air kerma measurements at fixed locations collected over an extended time period may also reveal magnitudes of uncertainties and variations due to fluctuations in ambient conditions and the appropriateness of temperature and pressure corrections, repositioning precisions, and drifts in electrometer performance. In this work, quality control measurements were conducted for a 259 GBq 137Cs irradiator using a National Institutes of Standards and Technology (NIST) traceable spherical ion chamber and electrometer. Measurements were made at the center of a 40 cm by 40 cm by 15 cm polymethyl methacrylate phantom, followed by six additional measurements at a distance of 9 cm radius from the center. Measurements were repeated on a near weekly basis over a 17-mo period. The statistical behavior of the recorded data, the appropriateness of pressure/temperature/humidity corrections, a comparison of response of different ion chambers, and the usage of control charts will be discussed.
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P.10 External Dosimetry
General Purpose Software for Thermoluminescent Dosimeter Glow Curve Analysis JM Hepker, University of Michigan
; JH Thiesen*, University of Michigan; JR Kuchta, University of Michigan; KJ Kearfott, University of Michigan
Abstract: The examination of thermoluminescent dosimeter glow curves is useful for the detection of abnormalities in dosimeter processing. When appropriately analyzed, glow curves hold added information about thermoluminescent material behavior. The mathematical separation of a glow curve into contributions from energetically different trap states, or glow curve analysis (GCA), may be utilized to remove undesired effects of signal fading for complex materials. GCA illuminates the material-specific models of thermoluminescence. In special circumstances, it could lead to improved statistical performance at low doses. Generalized computerized GCA software for deconvoluting glow curves was written in C++. The code optimizes the fitting process utilizing either a user-specified first-order kinetics model or a one trap-one recombination level model. The code was tested using experimental glow curve data from LiF:Mg,Ti, CaF2:Dy, CaF2:Tm, and CaF2:Mn. Glow curves from a variety of different readers may be analyzed with the code. Output consists of a list of fit parameters and deconvoluted gaussian data in comma-separated-value form for easy graphing and analysis. The adaptation of the code for data obtained using complex time temperature profiles may be possible.
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P.11 External Dosimetry
A Comparison of Age-dependent Organ Depth Distributions: Stylized Versus Voxel Phantom Series K Griffin, National Cancer Institute - National Institutes of Health
; SA Dewji, Texas A&M University; T Cuthbert*, Texas A&M University; C Lee, National Cancer Institute - National Institutes of Health
Abstract: The main parameter influencing organ dosimetry from external irradiation is the organ's position below the surface of the body. Initially, models of the human body were defined through surface equations (stylized phantoms) and have now been advanced by more anatomically realistic models based on medical patient images (voxel phantoms). The impact of this shift in modelling has been studied rigorously through comparisons of external dosimetry simulation results. For photon irradiation, differences in organ dose between the series are often interpreted as differences in organ depth and positioning. This work, however, represents the first effort to quantify the differences in organ depths between a stylized and voxel phantom series. For this work, the revised ORNL stylized phantom series and the voxel UF/NCI phantom series were used. Both series include whole-body models of the newborn; the 1-, 5-, 10-, and 15-year-old; and the adult human. Organ depths from six different directions applicable to external dosimetry were found: the caudal, cranial, left and right lateral, front, and back. In addition, rotational and isotropic organ dose depth simulations were computed. Organ depths in the stylized phantom were found through a ray tracing technique used in the Monte Carlo code MCNP6. Organ depths in the voxel phantom were found through phantom matrix manipulation. Resultant organ depth comparison plots have been created for twenty-four organs, for all ages, in each of the eight views. These plots are used to explain the results within a literature review of relevant photon external dosimetry papers which use these phantoms.
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P.12 External Dosimetry
CANCELLED - Computation of Spontaneous Fission External Dose Coefficients due to Contaminated Environmental Media H Kistle, Texas A&M University
; SA Dewji*, Texas A&M University
Abstract: CANCELLED
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P.13 External Dosimetry
Comparison of Organ and Effective Neutron Dose Coefficients for Reference Phantoms in Articulated and Upright Postures in Cranial and Caudal Irradiation Geometries K Bales, University of Texas Health Science Center at San Antonio
; A Perry*, Texas A&M University; SA Dewji, Texas A&M University
Abstract: Dose estimations have been traditionally conducted employing anthropomorphic phantoms in an upright posture. However, an exclusively upright posture could reduce accuracy when reconstructing or estimated organ absorbed and effective doses for exposures in realistic working postures. In this work, effective dose coefficients were computed using International Commission on Radiological Protection Publication 103 recommendations for monoenergetic neutron plane sources directed upward from below the feet (caudal) and downward from above the head (cranial) for articulated adult male and female stylized phantoms. The Monte Carlo radiation transport code and the Phantom With Moving Arms and Legs were used to calculate organ absorbed dose and effective dose coefficients for upright and two bent (45° and 90°) phantom postures. The resulting coefficients for the bent phantoms were compared to those for the upright phantoms to determine whether the upright phantoms provide a comparable and conservative estimate when conducting dose estimations/reconstructions.
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P.14 Instrumentation
Monte Carlo Simulations to Predict the Energy Discrimination Capability of a Novel Beta Particle Detector JW King*, Texas A&M University
; CM Marianno, Texas A&M University
Abstract: The radiation integrated circuit (RIC) is a novel radiation detector created at Texas A&M University (TAMU) which exploits a common failure of radiation-soft integrated circuits as a mechanism for the detection of beta particles. An unattenuated beta particle is likely to penetrate the RIC without interaction. Therefore, a wedged attenuator was proposed both to increase the probability of interaction and to allow for energy discrimination. Research at TAMU sought to use Monte Carlo simulations to predict the energy discrimination capability provided by four attenuator materials: plate glass, borosilicate (Pyrex®) glass, acrylic (Lucite®), and natural rubber. Monte Carlo N-Particle radiation transport code (MCNP6.1) simulations of the four materials subjected the attenuator to beta particles in the energy range of 1.95 to 2.10 MeV in 0.01 MeV increments. Beta particle flux was tallied along the surface of the attenuator opposite the beta particle source to observe the flux profile over the length of the attenuator. A distinct flux peak was observed for each energy studied. Peak locations trended linearly along the attenuator with high energy peaks in the thicker portion of the material and lower energy peaks in the thinner portion. A spatial energy resolution was calculated as the negative ratio of the maximum difference in particle energy and the maximum difference in flux peak location. These calculations showed natural rubber to have the best energy discrimination capability of 0.25 MeV per cm. The 1 cm x 1 cm RIC is designed with 70 linear detection elements arranged parallel to one another, 52 of which can be monitored individually. A simplified calculation finds that the natural rubber attenuator provides a resolution of about 4.8 keV per element. Given a peak spacing of 10 detection elements to ensure confident peak discrimination, the RIC may be able to discriminate maximum beta particle energy to about 50 keV with a natural rubber attenuator.
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P.15 Instrumentation
Performance of Soviet Geiger-Muller Tubes with a Computerized Do-It-Yourself Detector RM Dewald, University of Michigan
; BJ Shen, University of Michigan; RA Tuey*, University of Michigan; JM Miller, University of Michigan; LK Chung, University of Michigan; JD Noey, University of Michigan; KJ Kearfott, University of Michigan
Abstract: A simple boost converter was devised to work with an embedded computer to create an affordable radiation detector that could be built by high school students as part of nuclear science outreach. The costs of the electronic components and printed circuit board costs were less than $5 and the Raspberry Pi Zero W retails at ~$15. The most expensive portion of a system is thus the Geiger-Müller (G-M) tube , which retails for more than $50 new. While G-M tubes may be salvaged from 1950s-1970s era US fallout shelter detectors (such as the Victoreen CDV-700), these tubes may not be available in sufficient quantities to meet demand. In addition, CDV-700 tubes function best at voltages on the order of 1,000 V. This presents potential for minor electrical shock, enhances battery consumption, complicates circuit design, and requires slightly more expensive multimeters for circuit testing. While the adjustable metal case surrounding CDV-700 probes may prove useful for demonstrating a number of radiation detection principles, the necessary modification of the cable coming from the probe requires a process that is relatively tricky for the unskilled, and removal of the tube itself from the case is challenging. One solution to this concern is the usage of a variety of surplus G-M tubes from the former Soviet Union, such as the STS/CTC-5. These Soviet tubes are available for $5-$15 from a variety of internet marketplaces. For this work, a collection of 35 different models of legacy Soviet G-M tubes were obtained. Sensitivity as a function of voltage was measured using a point source at a fixed distance. The performance, availability, and costs of each Soviet G-M tube design were reviewed. As the current design allows G-M tubes to be easily exchanged, the availability of different types of tubes (such as both CDV-700 and STS/CTC-5 tubes) adds another, more advanced educational dimension to the system.
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P.16 Instrumentation
University of Michigan’s Computerized Do-It-Yourself Geiger-Muller Radiation Detector: Preparation for Outreach Programs RA Tuey, University of Michigan
; RM McClain, University of Michigan; JM Miller*, University of Michigan; LK Chung, University of Michigan; M Li, University of Michigan; BJ Shen, University of Michigan; RM Dewald, University of Michigan; FF Wisusik, University of Michigan; JD Noey, University of Michigan; KJ Kearfott, University of Michigan
Abstract: A computerized Geiger-Müller (G-M) radiation detector which high school students could assemble themselves presents several nuclear science outreach advantages over the provision of a single legacy G-M survey meter from a fallout shelter to a high school science teacher. Students would learn more fundamental skills relating to electronics, circuits, embedded systems, and cellphone applications while being able to keep their own system, which would include a small multi-purpose computer. The system is cheap, easily produced, and allows hands-on interaction for students, superior at fostering interest in nuclear science than just a teacher's demonstration. Since 2016, a multidisciplinary undergraduate team has developed the circuitry and software for a Do-It-Yourself G-M (DIYgm) system based around a Raspberry Pi and controlled by a cellphone. During the third year of the project, the team continued engineering the system to increase its practicality for programmatic deployment. Efforts included a substantial reduction in parts costs, redesign of the printed circuit board to simplify assembly, improved method for connecting the tube to the system, case design and cost reduction for different deployment circumstances, and introduction of 3-dimensional printing. Documentation and exercises suitable for individuals ranging from unskilled to expert were developed. Applications for both Android and Apple cellphones were written, improved, and documented. The construction and operation of the DIYgm were tested on nuclear engineering seniors as one module in a formal laboratory course on applied radiation detection.
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P.17 Instrumentation
Use of an Imaging Spectrometer for Characterization of a Cesium Facility RJ Champion*, University of Michigan
; RM Golduber, University of Michigan; LK Chung, University of Michigan; KJ Kearfott, University of Michigan
Abstract: A research and dosimetry calibration facility with a 269 GBq 137Cs source was established in a 2.8 m by 3.6 m basement space with a ceiling height of 3.4 m and 0.8 m thick concrete walls. It was previously found that backscatter and room return have a negligible effect upon standard phantom-based dosimeter calibration irradiations in the facility at a fixed distance. Because it is desirable to use the facility for research and educational purposes beyond dosimeter calibration, a more extensive characterization of the radiation field in the room was undertaken. This included measurements of air kerma as a function of position in a grid throughout the room with a standardized ion chamber and electrometer. Attempts were made to capture gamma ray spectra using a variety of sodium iodide, high purity germanium, and cadmium zinc telluride detectors. Thermoluminescent and optically stimulated luminescent detectors were deployed throughout the room to complete the study. A spectroscopic imaging device, with software adapted to visually display scatter spectra in addition to radionuclide photopeaks counts, was also deployed to image radiation in the facility.
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P.18 Instrumentation
Dose Calibrator Activity Measurement of Actinium-225 for targeted alpha therapy JG Kim*, Korea Institute of Radiological and Medical Sciences
; TW Lee, Korea Institute of Radiological and Medical Sciences; KH Song, Korea Institute of Radiological and Medical Sciences; WJ Yoo, Korea Association for Radiation Application; BS Kim, Korea Institute of Radiological and Medical Sciences
Abstract: The dose calibrators (ionization chambers) measurements of Actinium-225 were performed. We evaluated the measurement accuracy of the dose calibrators for the quantitative activity determination of the 225Ac. Five dose calibrators (three models) in our institutions were performed in this study. The user dial setting numbers were set to the decay correction value using the source measured with the dose calibrator and the source measured with the alpha spectrometer. The sources from two different activity values were kept in the same position in the detector chambers throughout the measurement. The 225Ac measurement variation for the dial setting was within 2 % in same model dose calibrators. When comparing different models, the dial setting number showed an error range within 10 %. The relative measurement error due to the geometry and volume of the sources due to the solid and liquid state was about 6.2 %. Our results showed the corrections with experimental calibrations numbers can be necessary. As there is no dial setting value officially provided by the manufacturer of the dose calibrator for the alpha nucleus, 225Ac, it is likely that adjustment of the cross-check and dial settings is required for accurate activity measurement at the user's institution.
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P.19 Instrumentation
World List of Early Nuclear Reactors, Africa and Asia. A Philatelic Look at Health Physics History. TP Johnston*, NIST
Abstract: Presented here we have a review of the early days of nuclear reactors worldwide. This poster will briefly cover the commemorative postal stamps of the countries that chose to honor the first operational nuclear reactor in their nation. In particular, a summary of some of the countries in Africa and Asia with reactors featured on their postal issues. These early reactors were generally of the research and test reactor type. Note: TRIGA reactor – Training, Research, Isotope production, General Atomics.
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P.20 Instrumentation
World List of Early Nuclear Reactors, Europe. A Philatelic Look at Health Physics History. TP Johnston*, NIST
Abstract: Presented here we have a review of the early days of nuclear reactors worldwide. We continue with an overview of initial examples of nuclear reactors in Europe. This poster will briefly cover the commemorative postal stamps of the countries that elected to honor the first operational nuclear reactor in their nation. In particular, a brief review of the countries of the European continent with reactors featured on their postal issues.
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P.21 Instrumentation
World List of Early Nuclear Reactors, the Americas and Antarctica. A Philatelic Look at Health Physics History. TP Johnston*, NIST
Abstract: Presented here we have a review of the early days of nuclear reactors worldwide. We continue and finish with a final review of nuclear reactors featured on the postal issues of countries in the Americas and a special cancel from Antarctica. Several of the commemorative stamps feature the atomic or nuclear energy commission of the respective country, or the IAEA. There are a few stamps that highlight nuclear reactors. In general, after a mention of the United States and Puerto Rico, followed by Antarctica, we will cover the countries of the Americas in alphabetical order.
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P.22 Instrumentation
Development of an Optical Sensor to Measure Opacity Changes in Polyvinyl Toluene Scintillators EA Ordonez*, Texas A&M University
; CM Marianno, Texas A&M University; JW King, Texas A&M University; R Suh, Texas A&M University
Abstract: Polyvinyl toluene (PVT) based detectors are used in radiation portal monitors (RPMs) throughout the world to detect the trafficking of illicit nuclear material. PVT scintillators have been observed to suffer internal clouding due to prolonged exposure to environments with high temperatures and high relative humidity followed by freezing temperatures. This ultimately affects transmission of light through the material and decreases overall RPM performance. An Opacity Monitory System (OMS) was developed to measure and track changes in PVT opacity in-situ. This was accomplished by employing an array of different colored light emitting diodes (LEDs) and an optical sensor (OS) to measure light transmission. The changes in opacity were tracked by separately flashing each LED for one second and recording the light intensity transmitted through the detector with an OS. The placement of the OMS on the detector consisted of the LED array at the center of one of the larger faces of the 3.8 cm x 7.5 cm x 15 cm PVT with the OS positioned directly across from the array. The OMS and detector were then placed inside an environmental chamber where the temperatures and relative humidity cycled between -20°C to 55°C and 40% to 100%, respectively, for 888 hours. During these temperature cycles the reduction in opacity was observed through the reduction of transmitted light. Depending on the color of light being observed, light transmission was reduced by as much as 50% at the coldest temperature. Similar tests were conducted with the OMS without PVT present resulting in zero reduction in recorded light output. These results indicate the OMS is an effective tool in determining PVT opacity in-situ.
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P.23 Academic Institutions
Revision of an Undergraduate Health Physics Program for a New Generation PC Fulmer*, Francis Marion University, Florence SC
; DW Jokisch, Francis Marion University, Florence SC
Abstract: Francis Marion University has one of the few undergraduate degrees in the country with emphasis in health physics. Although the program has been in existence since the early 1980s, it has seen a profound amount of modification in the last several years. These changes were undertaken with the goal of having students ready to perform at the professional level (as opposed to the technician level) in the workplace or to be ready for graduate school with knowledge that would be comparable to a second-semester graduate student. These revisions to the program involved the addition of new courses, the introduction of computational methods into classes at all levels, expansion of the electronics class to include microcontrollers and scientific instrument design, an expanded nuclear physics laboratory with greater emphasis on detector theory and operation, and improved practical exercises that prepare the students even more for the workplace or for advanced degrees. This presentation will give details on the courses offered within the bachelor's degree and the technical content offered in each class. Innovations in computational methods in these classes will be detailed as well, both in training students to use existing radiation protection/health physics software in addition to designing calculational tools to perform health physics-related calculations. Further, lab courses will be discussed with descriptions of the newest equipment, upgrades in experimental techniques, and the use of engineering principles to guide the students to design solutions to real-world health physics problems. Finally, practical exercises in which students participate to gain real-world experience along with required summer internships will be discussed along with their importance in giving students a connection between classroom studies and the application of classroom principles to real-world applied problems.
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P.24 Emergency Response
Southern Urals Regional Emergency Medical-dosimetry Center. The Experience VA Marov*, Southern Urals Biophysics Institute of the FMBA of Russia
Abstract: Three emergency centers of the FMBA of Russia are established in Russian Federation. These centers provide medical response to radiation accidents and incidents. All the centers are parts of forces and facilities of instant readiness at the federal level of the unified state system for prevention and emergency response. Its area of responsibility includes Ural, Siberian and Far East Federal districts. Sixteen large-scale radiation hazardous objects are located within the Center's area of responsibility. The specialists of the Center along with the State Corporation "Rosatom" had developed scenarios for probable emergency situations for each of the enterprises and for hazardous influence factors in effect in each case. The Center has the devices of dosimetry monitoring and pharmaceutical products for minimizing the consequences of radiation exposure of personnel and population. The Center performs a variety of scientific work for development of standardized methodological documents that regulate the issues of radiation safety and monitoring of external and internal exposure of personnel at radiation hazardous enterprises. The Center performs research work in the field of applying EPR for external dosimetry. In 2017 the Center took part in medical-support in the course of FIFA Confederations Cup in Kazan, in 2018 in the FIFA World Cup in Yekaterinburg, it will work at the Winter Universiade in Krasnoyarsk. In 2017 in Kemerovo region 2 containers with radioactive sources of Cs-137 were found in one of the garages. The specialists of the Center performed measurements and monitoring the situation. The level of ambient equivalent dose rate was 1500 µSv/hour, natural background was 0.12 µSv/hour. The containers were passed for utilization. That situation was hazardous for population, the source was out of control; that is why it had the status of "radiation accident" and was classified according to INES scale as level 2
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P.24.5 Emergency Response
A Novel Approach to Tomographic Imaging for Internalized Dose Estimation for At-Risk Members of the Public C O'Connell*, Texas A&M University
; C Foreman, Texas A&M University; B D'Souza, Texas A&M University; N Caldwell, Texas A&M University; T Cuthbert, Texas A&M University; SA Dewji, Texas A&M University
Abstract: After an emergency radiological dispersion (RDD) event, triage survey devices can be employed by first responders to evaluate at-risk individuals in the case of internal uptakes during an exposure incident. Current devices however, are very limited in their ability to assess a wide variety of at-risk members of the public such as infants, the disabled, and the geriatric population. Current devices also lack the ability to detect more than one radionuclide. The objective of the project is to design a rapid triage device to be used on-site by first responders that is capable of assessing dose for any at-risk member of the public with the ability to detect Cs-137, Co-60, and I-131. Modeling efforts included integration of time dependent biokinetics models with radiation transport modeled in MCNP, and user software used created using MATLAB. The preliminary design for the proposed device includes an array of scintillation detectors. The creation of a flat plane will allow for the pixilation of the exposed person. The measurement device will include a bed for the patient to lay on which will accommodate multiple positions (prone, supine, etc.), while an array of detectors will be mobile and pass over the receptor. The array design of detectors will allow the device to output an estimated dose in each organ and produce a body dosage map on site for use in triage, not before available for the supine position, representing the range of members of the public.
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P.25 Air & Environmental Monitoring
The Use of Administrative Monetary Penalties in Nuclear Safety J Vucicevic*, University of Ontario Institute of Technology
; E Waller, University of Ontario Institute of Technology
Abstract: The paper presents research on the Administrative Monetary Penalties (AMP) in Canada and their usage in nuclear safety. An AMP is a penalty imposed by the Canadian Nuclear Safety Commission (CNSC), without court involvement. It is used in the case of a violation of a regulatory requirement. An AMP can be applied against any individual or corporation subject to the Nuclear Safety Control Act, which regulates the development, production and use of nuclear energy and the production, possession and use of nuclear and radioactive material. However, AMPs are not the same as criminal offences. They are civil sanctions which try to secure compliance through the application of monetary penalties for non-compliance with regulatory requirements. The AMP program was introduced in 2013 in Canada and in all of the penalties issued, the violations were related to the handling and safety of radioactive material. Based on these issued penalties, research was conducted to discover pros and cons of the AMP system and to recommend improvements for future implementation. It also addressed some of the main concerns of the system, such as the economic aspect of the process, and the subjectivity and relative ease of issuing these penalties. The main goal of AMPs is not to punish, but to promote compliance. In order to improve nuclear safety in Canada, the regulator has to be aware of possible violations of the Nuclear Safety Control Act and work on prevention of these violations. Current AMP policy does not motivate individuals or corporations to report violations. The paper gives recommendations on modifications which could be implemented to motivate self – identification of violation, and give significant benefit to the AMP system. Other than the issued AMPs, the paper will analyze data obtained through the survey conducted on human readiness to self – identify violations in nuclear industry under different circumstances. It will also compare the AMP system in Canada with US regulations, as well as in other industries. This should confirm that the modified AMP policy would improve the body of knowledge and provide significant information on violations of the Nuclear Safety Control Act and improve nuclear safety.
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P.26 Air & Environmental Monitoring
Status of Zooplankton Communities of Radioactively Contaminated Reservoirs of “MAYAK” Production Association AY Aldibekova*, URCRM, Russia
; EV Styazhkina, URCRM, Russia; DI Osipov, URCRM, Russia
Abstract: For many years, the water bodies of the Techa Reservoir Cascade were used as storage-reservoirs of liquid waste at “MAYAK” Production Association (South Urals, Russia). Radionuclide levels in these reservoirs are higher than that in the comparison reservoir (Shershni reservoir) by several orders of magnitude, which makes it possible to study radiobiological patterns of zooplankton communities response to chronic radiation exposure. Hydrobiological studies were carried out in 2016 on the reservoirs of the Techa Reservoir Cascade: R-11, R-10, R-4, R-3 and reservoir R-17.
In the course of samples analysis three main zooplankton species were found: rotifers (Rotifera), cladoceras (Cladocera), and copepods (Copepoda). The following parameters were analyzed: number of species in a sample, abundance, biomass, Shannon and Margalef indices.
The zooplankton from the Shershni reservoir was characterized by the biggest species diversity (number of species per sample 22.8±8.2). Reservoir R-17 was statistically significantly less rich in species diversity (4.7±0.6). Species diversity of the reservoirs R-11, R-10, R-4, and R-3 was comparable to that of the Shershni reservoir (21.2±3.4; 20.4±0.9; 19.3±2.2; 13.7±3.1, respectfully). Total dominance of rotifers (Rotifera) (100% of all zooplankton species), which implies adverse environmental conditions, was registered in R-17 where the absorbed dose rate was 40 mGy/day.
The obtained parameters characterizing zooplankton communities (ShR, R-11, R-10, R-4, R-3, and R-17) were later used for regression analysis. Exponential function describes well the response of such parameters, as the number of species per sample (R2=0.98; p<0.01), the Shannon index (R2=0.996; p=0.01), and the Margalef index of species diversity (R2=0.995; p<0.01) to the absorbed dose rate. Thus, we can draw a conclusion that with an increase of absorbed dose rate there is a simplification of zooplankton community structure.
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P.27 Air & Environmental Monitoring
Natural Radioactivity Measurement And Dose Assessment Of Excavated Soils and Well Waters Of Southwestern Nigeria BB Oladele*, Federal University of Technology Akure. Nigeria.
; CG Dike, Federal University Of Technology Akure. Nigeria.
Abstract: The activity concentrations of 238U, 232Th and 40K in the soil and water samples were measured using a sodium iodide NaI(Tl) detector. The result obtained showed that the mean values of the activity concentrations of 238U, 232Th and 40K in the soil samples were 32.71±3.82, 37.04±3.71, and 497.67±12.30 Bq kg-1 respectively. The mean activity concentrations of 238U, 232Th and 40K in the water samples were 1.43±0.19, 1.44±0.23, and 36.75±3.82 Bq l-1 respectively. The radiological health risk associated with the measured radionuclides in the samples was assessed. For the soil samples, the mean values of the absorbed dose (D), annual effective dose equivalent (AEDE), Radium equivalent activity (Raeq), internal hazard index, external hazard index, annual gonadal equivalent dose and the excess lifetime cancer risk (ECLR) are 57.58 nGy h-1, 0.07 mSv y-1, 122.70 Bq kg-1, 0.42, 0.33, 407.30 mSv y-1 0.91 and 0.25 respectively. The values obtained for the annual effective dose were lower than the maximum permissible limit of 1 mSv y-1 recommended by ICRP. Hence, dwellers of the study area may not suffer any serious health risk as a result of exposure to ionizing radiation emitted by the natural radionuclides in the study area.
*Keywords: *Radionuclides, *Ionizing radiation, *Exposure, *Soil samples, *Water samples, *Annual Gonadal Equivalent Dose, *Internal hazard and External hazard Index, *Excess Lifetime Cancer Risk.
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P.28 Air & Environmental Monitoring
Modeling of Radiocesium Urban Washoff and Fate in Wastewater Treatment Plant GM Ng*, Oregon State University
; KA Higley, Oregon State University
Abstract: Following the Chernobyl and Fukushima nuclear plant accidents, radioactive sludge was observed from municipal wastewater treatment plants (WWTPs), originating as washoff from contaminated urban catchments. This has implications for its disposal via agricultural application, incineration or local landfills. In the areas affected by the Fukushima nuclear plant accident, radioactive sludge exceeding the regulatory limit of 8,000 Bq/kg were reported and interdicted from land application or municipal landfills. Instead, the sludge was stored on-site in the WWTPs, posing a logistics and handling issue. Hence, a predictive capability for sludge contamination could help WWTP operators to preempt in event of a radiological incident. Given the spatial-temporal complexity of urban catchment, paucity of urban radiological washoff data and the dynamic operation of diverse configurations of WWTPs, there are few efforts in modeling this pathway. To address this need, a model coupling of a semi-distributed urban washoff program, US EPA Storm Water Management Model 5 (SWMM), with a calibrated WWTP compartment model in STELLA is being developed and will be used to calculate sludge contamination in a hypothetical scenario. Sensitivity analysis results will also be presented. Recognizing the current limits in accurate prediction, this work, nevertheless, contributes to a mechanistic model of this pathway.
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P.29 Air & Environmental Monitoring
Development and Comparison of Plant-specific Dosimetric Phantoms DA Montgomery*, Clemson University
; NE Martinez, Clemson University
Abstract: Three anatomically representative computational phantoms were developed for the grass species Andropogon virginicus, an indigenous grass species in the Southeastern United States. Specifically, the phantoms developed in this work are: (1) a stylized phantom where plant tissues (roots or shoots) are represented by simple geometric shapes, (2) a voxel phantom developed from micro-CT imagery of a plant specimen, and (3) a hybrid phantom resulting from the refinement of (2) by use of NURBS surfaces. For each computational phantom, Monte Carlo dosimetric modeling was utilized to determine whole-organism and tissue specific dose coefficients (DC) associated with external and internal exposure to 99Tc, 137Cs, 237Np, and 238U for A. virginicus. Model DCs were compared to each other and to current values for the ICRP reference wild grass in order to determine if noteworthy differences resulted from the utilization of more anatomically realistic phantom geometry. Modeled internal DCs were comparable with ICRP values. However, modeled external DCs were more variable with respect to ICRP values; this is proposed to be due to differences in organism and source geometry definitions. Overall, the three anatomical phantoms were reasonably consistent. Some noticeable differences in internal DCs were observed between the stylized model and the voxel or hybrid models for external DCs for shoots and for cases of crossfire between plant tissues. Additionally, uptake data from previous hydroponic (HP) experiments was applied in conjunction with hybrid model DCs to determine dose rates to the plant from individual radionuclides as an example of practical application.
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P.30 Air & Environmental Monitoring
Investigation of Variations in Gamma Rays Detected by the EPA Air Monitoring Systems Located in Pennsylvania N Fallahian, Bloomsburg University
; D Zhang, Bloomsburg University; TA Ambrose*, Bloomsburg University; DR Simpson, Bloomsburg University
Abstract: The Environmental Radiation Air Monitoring Network known as RadNet, operated by the United States Environmental Protection Agency, consists of 140 stationary air samplers installed in all 50 states including three in Pennsylvania. These systems measure gamma rays emitted from airborne radioactive particulates collected on their 10 cm-diameter synthetic fiber filters, and transmit near-real-time data to EPA’s National Analytical Radiation Environmental Laboratory (NAREL) in Montgomery, AL using cellular and satellite antennas. In this study, the hourly fluctuations in gamma rays detected by 2x2 NaI (Tl) detectors in RadNet systems located in Bloomsburg, Pittsburgh and Philadelphia were examined. To determine the major contributors to these variations, the hourly data on key environmental factors such as cosmic rays, precipitation, humidity, and wind speed were collected in these areas for a period of three years. The correlation between these factors and gamma gross count rates were investigated using the statistical analysis software (SAS). Precipitation, humidity and cosmic rays showed a positive correlation with detected gamma rays; however, the effect of humidity was much more significant. Wind speed was found to have a negative correlation with gamma rays. The obtained results strongly suggest that gamma ray fluctuations in all three stations located in Pennsylvania are mainly due to changes in radon concentrations in air and variations in cosmic rays.
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P.31 Air & Environmental Monitoring
Low Dose Retrospective Dosimetry on Shelled Aquatic Species A Hassan*, University of Ontario Institute of Technology
; EJ Waller, University of Ontario Institute of Technology
Abstract: Electron paramagnetic resonance spectra on American lobster (Homanus americanus) and freshwater snail (Pila globosa) shells were studied to determine their suitability as effective detection indicators for radioactive environmental contamination. Prepared samples were irradiated to doses of 3, 5, 10, and 13 Gy using a Cs-137 gamma irradiator to detect the radiation induced signal, with optically stimulated luminescence dosimeters and alanine used as reference dosimetry. At 34 cm from the source, samples were irradiated at a dose rate of 0.182 Gy/hr. At the target doses, characteristic Mn2+ peaks were visible for both samples. However, after isolating for the irradiation peak, no radiation induced signal was observed in the lobster sample, thereby identifying lobsters to be unsuitable for environmental dosimetry. Snail shells displayed a strong radiation induced signal at the target doses and will be further investigated for studies on detection limits and sample preparation methods, with various types of gastropod species being considered.
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P.32 Air & Environmental Monitoring
Investigation of the Bioavailability of Radiocesium in the Fukushima Exclusion Zone using a Sequential Extraction Technique IM McNabb*, Colorado State University
; R Sudowe, Colorado State University
Abstract: The nuclear reactor accident at the Fukushima Daiichi power plant in March of 2011, resulted in the release of large quantities of various radionuclides into the environment. The main radionuclide of concern still remaining today is cesium-137 due to its 30-year half-life. Several areas in the vicinity of the power plant are still considered an exclusion zone owing to contamination with radiocesium, and they have not been cleared for human resettlement. While these parts are not suitable for permanent habitation, they are accessible for field work. The purpose of this research was to analyze the movement and bioavailability of radiocesium in the ecosystems contaminated by fallout from the Fukushima Daiichi nuclear reactor accident. This was achieved by analyzing soil cores collected from within the exclusion zone. The core samples were run though a 5-step sequential extraction technique, which exposes the soils stepwise to an increasingly aggressive chemical treatment. Each step targets a specific soil host phase: exchangeable, carbonate bound, Fe/Mn bound, organic, and residual. The results of this extraction yielded the following Cs-137 activity (percent of total): 0% exchangeable, 1-16% carbonate bound, 0-5% Fe/Mn bound, 1-5% organic, 44-67% residual, and 25-47% non-extracted. These results show that most of the Cs-137 is irreversibly bound to clays in the soil yet there is differences between soil sampling sites in amount of Cs-137 successfully extracted in the carbonate bound, Fe/Mn bound, and Organic, which provides evidence that Cs-137 mobility and bioavailability is partly dependent on local soil mineralogy and chemistry.
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P.33 Air & Environmental Monitoring
Uncertainty of the Results of the Radon Control in Housings. The Problem of Assessment of the Radon Concentration and Modern Control Principles AA Tsapalov, Institute of Mineralogy, Geochemistry and Crystal Сhemistry of Rare Elements , Russia
; SM Kiselev*, SRC Burnasyan Federal Medical Biophysical Center of the FMBA of Russia, Moscow, Russia; AM Marennyy, Federal State Unitary Enterprise Research and Technical Center of Radiation-Chemical Safety and Hygiene of the FMBA of Russia, ; KL Kovler, National Building Research Institute, Faculty of Civil and Environmental Engineering «Technion» – Israel Institute of Technolog; SI Kuvshinnikov, Federal Service for Surveillance on Consumer Rights Protection and Human Well-Being, Moscow, Russia; Kiselev
Abstract: Radon control in buildings is being performed for decades in different countries of the world, including Russia. However, there is a lack of a unified standard for the assessment of the uncertainty of the results of the control, considering the protocol and duration of the measurements. It is obvious that the uncertainty of the control increases with the reduction of the duration of the measurements. The lack of data on confidence interval for the average annual radon concentration in housings does not allow correct and precise comparison with the regulatory level, both for the commissioned and operated buildings. Additionally, it complicates the development of the effective method, mass control strategy and identification of buildings with high radon concentrations. A reliable method of control, considering time variations of radon and duration of exposure, was developed in Russia several years ago, but it is not well-known and not applied on practice. The presented work is focused on a novel principle of radon control, based on simple criteria, widely used in metrology and complying to the modern standards. This principle introduces a new parameter – the radon time variation coefficient KV(t), which reflects main constituent of the uncertainty of the average annual radon concentration depending on the protocol and duration of the measurements. A novel algorithm for the estimation of KV(t) is proposed, developed on the base of the results of continuous annual radon monitoring in representative experimental housings. Additionally, the structure of the correcting coefficient is presented, considering an impact of the temperature on the radon behavior.
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P.34 Air & Environmental Monitoring
Radon Kinetics in a Natural Indoor Radon Chamber LA Mata, University of Michigan
; YJ Ye, University of Michigan; LK Chung*, University of Michigan; MA Carmona, University of Michigan; TE Maurer, University of Michigan; NA Shubayr, Jazan University; Q Zhou, University of South China; KJ Kearfott, University of Michigan
Abstract: An unusual 180 m3 storage room in the basement of a two-story laboratory building is unventilated, and separated from occupiable rooms by double steel doors. The space completely borders on soil through the concrete floor and two of its concrete walls. The room also contains a separate inner chamber with 1 m thick concrete walls designed to damp vibrations in the room above it. The space boasts a relatively high radon level, 1,100 Bq m-3, which varies with local outdoor environmental conditions. Measurements were made of radon concentrations at various locations and heights within the facility. More than one year of continuous radon concentration data corresponding a single location are also available, along with corresponding measurements of indoor and outdoor pressure, temperature, and humidity. Data were also collected with as many as four fans placed in different locations and cycled on for variable time periods. A first order linear kinetic model was created to explain the observed approaches to steady state due to changing conditions and washout resulting from intentional ventilation. Attempts were made to correlate environmental conditions with observed radon gas. Experimental data were also compared with simulations conducted using computational fluid dynamics models.
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P.35 Air & Environmental Monitoring
Evolution of the University of Michigan's Radiation Weather Station System for Research and Public Outreach TE Maurer*, University of Michigan
; LK Chung, University of Michigan; WJ White, University of Michigan; KJ Kearfott, University of Michigan
Abstract: Since 2015, an temporally changing interdisciplinary team of University of Michigan undergraduate students have been engaged in the development of affordable instrumentation and reliable data management approaches for the continuous monitoring of radiation and meteorological parameters. The overarching goal of the effort is a loosely networked collection of radiation detectors and other sensors installed in different locations for educational and research purposes. Indoor and outdoor deployment is ultimately anticipated for radically different venues, including museums, community centers, high schools, colleges and universities. The available resources and skill levels of those interacting with these Radiation Weather Stations (RWS) are likely to be extremely diverse. The plan is that all data, along with educational information, are to be made fully accessible to the public through a friendly website. The work presented here will include recent efforts targeted on website development, instrumentation, sensor reliability, data management, overall system robustness, and documentation. Collecting data from very different devices and a complex and ever-changing university computer network present continuing challenges. Comprehensive documentation is essential because of the anticipated lack of personnel continuity with an undergraduate student team.
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P.36 Air & Environmental Monitoring
Development of Korea's Radiation Safety Information System : Identifying Challenges and Developing Functions MK Kim*, Korea Institution of Nuclear Safety
; JY Kim; JS Yang; JH Lee; KH Lee; BH Lee
Abstract: The RAdiation Safety Information System(RASIS) is used by independent central administrative and regulatory body NSSS(Nuclear Safety and Security Commission), regulatory expert organization KINS(Korea Institute of Nuclear Safety), radiation-related organization and 8,300 licensee(authorized user 1,500 and notificated user 6,800). It contains a wide range of radiation safety management information including application of regulation, life-cycle of radioisotopes & radiation generator, report on the status of radiation safety management of authorized user, Q&A history and radiation safety information. Each module of this system was first developed as a different site in 2001 before renewal. Therefore, there was a lack of consideration for data linkage between each piece of information.
In the meantime, new regulations were introduced and IT technology developed. As the number of licensee increased, the demand for the system reorganization and high-speed increased especially. We have upgraded this old system over the last three years, and we want to share the key considerations; ① Strengthening control of radiation safety, ② Increase user convenience, ③ Ensuring statistical accuracy.
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P.37 Air & Environmental Monitoring
Numerical Simulation of Radon Concentration Distribution in a Discovered Radon Chamber with and without Fans Y Ye, University of Michigan
; LA Mata, University of Michigan; Q Zhou, University of South China; J Huang, University of South China; LK Chung*, University of Michigan; Y Morishita, Japan Atomic Energy Agency; MA Carmona, University of Michigan; W Liu, University of South China; KJ Kearfott, University of Michigan
Abstract: The underground radon chamber of the University of Michigan is unventilated and isolated from other building spaces. The soil adjacent to the concrete floor and two of the chamber's walls is its main radon source. In order to understand the spatial variability of radon concentrations in the underground radon chamber, mathematical models of gas flow and radon migration in the indoor space were established. Consistent with actual building structure and geometry, a detailed three-dimensional physical model was created and the corresponding boundary conditions were determined. Next, computational fluid dynamics simulations were employed to investigate the temporal changes and spatial distribution of radon concentration in the underground radon chamber before and during operation of different numbers of fans in different positions. The results show that: (1) without the fan, radon migrates mainly by diffusion: the closer a location is to the floor and/or a wall adjacent to soil, the higher the radon concentration is; 2) the airflow blown by the fan can enhance the convective migration of radon in the chamber, but under the influence of the partition wall in the radon chamber, the position and the number of the fans have a significant influence on the radon concentration distribution.
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P.38 Air & Environmental Monitoring
Numerical Simulation of Radon Migration and Exhalation Rules of Loose Porous Emanation Media during Measuring of the Radon Exhalation Rate Y Ye, University of Michigan
; LA Mata, University of Michigan; Q Zhou, University of South China; G Chen, University of South China; H Su, University of South China; LK Chung*, University of Michigan; Y Morishita, Japan Atomic Energy Agency; MA Carmona, University of Michigan; KJ Kearfott, University of Michigan
Abstract: In order to understand radon migration and exhalation rules of loose porous emanation media during radon exhalation rate measurements, a mathematical model of radon migration in porous media was established based using seepage-diffusion transfer theory. According to the structure of the measuring device, the three-dimensional physical models of open flow, closed cycle and static accumulation methods for measuring radon exhalation rate were created, and their boundary conditions were determined. Computational fluid dynamics simulations were employed to simulate radon migration from porous media to the radon collector. The radon concentration distributions in porous emanation media and the radon collector were measured as a function of time. Based on the results of numerical simulation, the effects of permeability coefficient, effective diffusion coefficient, and gas flow rate on radon exhalation were analyzed when different measurement methods of radon exhalation rate were used.
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P.39 Air & Environmental Monitoring
Study of the Reliability of Soil 222Rn and 220Rn Concentrations Measured with In-Situ Diffusion Chamber Methods YJ Ye, University of Michigan
; LK Chung*, University of Michigan; Q Zhou, University of South China; KJ Kearfott, University of Michigan
Abstract: Rn222 and Rn220 are among the most important sources of natural exposure in the world. Soil is one of the significant sources of radon/thoron due to both radium and thorium. Accurate measurement of soil radon concentration is very important because it is a key physical parameter for evaluating radon release capacity of soil. In order to evaluate the reliability of gas extraction and in-situ diffusion chamber methods, computational fluid dynamics simulations were employed to investigate the change and distribution of radon concentration in soil before and during measurements with both methods. For the gas extraction method, the influence of the direction and size of the extraction gas port, the flow rate and the duration time of extraction gas on the distribution of soil Rn222 and Rn220 concentration were studied. For the in-situ diffusion chamber method, the influence of the dimensions of the diffusion chamber and diffusion coefficient of filter materials on the soil Rn222 and Rn220 concentration distributions were examined. Simulations were compared to the results of experimental measurements.
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P.40 Air & Environmental Monitoring
Evaluation of Radiological Health Hazard Parameters of Selected Fertilizers- A Statistical Approach P Clark*, Alcorn State University
; L Wilson, Alcorn State University; J Brandon, Alcorn State University; J Billa, Alcorn State University; S Adzanu, Alcorn State University; J Adjaye, Alcorn State University; M Ankrah, University of Kentucky
Abstract: Usage of fertilizers is one of the common practices employed in the farming industry as fertilizers can enhance crop yields and rate of production. Within the three types of fertilizers (N-P-K) used in the farming industry, the phosphate and potash based fertilizers tend to contain trace quantities of naturally occurring radioactive materials (NORM) as they are derived from Phosphate and Potash rocks. The NORM concentrations in fertilizers vary based on rock’s origin and amount of rock used in fertilizer production. A study on selected fertilizers was performed focusing on radioactivity measurement and their implications on human health. Gamma spectrometry was performed on two types of fertilizers (0-46-0) and ( 0-0-60) ( produced in the state of Mississippi) to measure the key isotopes of Ra-226 and K-40. From the obtained radioactivity values, some of the radiological health hazard indicating parameters- radium equivalent, gamma index, absorbed dose, and annual effective dose were estimated. A statistical comparison of the obtained values with the world-wide average values was performed using a one-tailed t-test at p= 0.05 (95% confidence interval). The obtained results suggest that the radioactivity levels in the samples analyzed are significant and federal organizations must provide additional recommendations on the usage and handling of NORM enhanced materials (fertilizers) considered in this study.
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P.41 Air & Environmental Monitoring
Assessment of Isotopic Transfer Factors in Sweet Potatoes J Vattikonda*, Alcorn State University
; B Akuana, Alcorn State University; M Amankwah, Alcorn State University; Y Bolton, Alcorn State University; J Billa, Alcorn State University; S Adzanu, Alcorn State University; J Adjaye, Alcorn State University; M Ankrah, University of Kentucky
Abstract: Plants absorb various nutrients present in soils and ground water via the root system during their growth period. To improve crop yields, farmers add fertilizers to soils and plants tend to uptake nutrients in fertilizers during their growth process. Presence of radioisotopes in soils may result in uptake of radioisotopes into plants and may eventually accumulate in the edible parts of the plants. Root plants such as sweet potatoes would be an excellent source for providing information on uptake rates of nutrients from soils. Being one of the prominent producers of sweet potatoes in the country, in year 2017 the state of Mississippi harvested 29,000 acres of sweet potatoes with production value of $123 million. Soils and sweet potatoes produced from Claiborne County of Mississippi were analyzed for the key isotopes of Ra-226, Th-232, and K-40 using a high purity germanium detector of 35% relative efficiency. Using the measured radioactivity values, the isotopic transfer factors (TF) from soils to edible parts of sweet potato plants were computed. As there is limited or no information on the levels of isotopic concentrations in sweet potatoes produced in the region of interest, results from this study serve as a template for researchers and agriculturalists on the levels and uptake rate of nutrients (radioisotopes) in sweet potatoes.
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P.42 Air & Environmental Monitoring
Assessment of Radionuclide Contents in Soil Samples in the Vicinity of a Coal Fired-power Plant in Mississippi U Gella*, Alcorn State University
; M Beitollahi, University of Utah; J Billa, Alcorn State University; S Adzanu, Alcorn State University; J Adjaye, Alcorn State University; M Ankrah, University of Kentucky
Abstract: The demand for energy is increasing drastically. Coal is one of the dominant fossil fuel sources that is abundantly available and is used in thermal power plants. In the United States, coal contributes about 25% of electricity generation. However, the contribution of coal to the world’s total energy production is around 40%. During the coal combustion process, coal fly and bottom ashes containing natural radionuclides in higher concentrations are released into the environment. Disposal of the coal bottom ash in open and unlined ponds causes environmental contamination via migration of radionuclides into soils and water. Eventually these processes will increase the concentrations of natural radionuclides in aquifer system. To estimate the levels of natural radionuclides in soils near a coal ash pond in state of Mississippi, a set of 40 samples were collected in the Area of Interest (AOI) and evaluated using gamma-spectroscopic techniques. The mean activity concentrations of Ra-226, Th-232 and K-40 were determined to be 37.56 ± 10.47 Bq kg-1, 38.43 ± 7.68 Bq kg-1, and 260.26 ± 71.19 Bq kg-1 respectively, in air dried soil samples. The obtained mean concentration values are statistically compared to the world-wide average concentrations of selected isotopes using a one-tailed t-test at 95% confidence interval (CI). The results of this study were used to assess the various radiation hazard indices of soil to the residents of the area. Based on the activity values obtained from this study, the average outdoor absorbed dose was estimated to be 52.07 ± 0.64 nGy/hr.
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P.43 Air & Environmental Monitoring
Pitchblende. A Philatelic Look at Health Physics History. TP Johnston*, NIST
Abstract: Pitchblende is also known as uraninite. The word comes from pitch or pech, meaning black or bad luck because of its black color, and blende. As health physicists we know about pitchblende and the work of Marie Skłodowska Curie and Pierre Curie in 1903. This poster will review the known uses of Uranium over time and the story is told with a graphical accompaniment of philatelic material (postage stamps). The story featuring Uranium begins with: the work of the Curie's, highlights the natural reactor in Gabon, a discovery of the first use of Uranium in Rome, miner's lung disease in the 1500's, a tie-in with President Herbert Hoover, a coloring agent for the ceramic and glass industries, silver mines and the U.S. dollar, more connections to the Curies and Becquerel, revelation of where those Coleman lantern mantles came from, a link to respiratory protection, spas in Jáchymov, and the finish courtesy of Fiestaware.
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P.44 Air & Environmental Monitoring
CANCELLED - Evaluation of Radioactivity Levels in Soilless Growth Media Collected From Agricultural Research Site in Tallahassee, Florida. GK OSEI*, Florida A&M University, Tallahassee
; LW NGATIA, Florida A&M University, Tallahassee; MD ABAZINGE, Florida A&M University, Tallahassee; A BOLQUES, Florida A&M University, Tallahassee; JK BILLA, Alcorn State University, Mississippi; C Jagoe, Florida A&M University, Tallahassee
Abstract: Cancelled
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P.45 Department of Energy Facilities
Investigation of the Creation and Spread of Contamination During Rapid Oxidation of Depleted Uranium Pressed Powder Pellets. DA Hollaway*, Idaho National Lab
; RL Beck, Idaho National Lab
Abstract: At the Idaho National Laboratory (INL) research and development activities are conducted for the Department of Energy (DOE). Part of this research is to investigate new and alternative manufacturing methods for nuclear fuel fabrication. Using metal-based (Uranium) powder material pressed into pellets in this research presents a pyrophoric hazard. Therefore, an understanding of the contamination created and spread during accidental and intentional oxidation of the uranium powder pellets is desired. An experiment was conducted, in collaboration with Researchers and Radiological Engineering (RE) at the INL, to intentionally oxidize various depleted Uranium pressed powder pellets. The authors focused on the spread of contamination and release of airborne material (airborne release investigation was conducted by RE). As part of the experiment six samples were staged in different arrangements. Each sample was oxidized individually and surveys were conducted after each oxidation event. Decontamination of the area was conducted after each oxidation event was complete to provide a consistent starting point. During the experiment, two different methods of extinguishing the oxidation of the uranium were tested. The first was to pour MET-LX powder over the oxidizing pellet, and the second was to apply a bag containing MET-LX powder directly on the oxidizing pellet. Of the two, the latter was more successful in containing the spread of contamination than pouring the MET-LX powder. As a result of our investigation, it was concluded that the spread of contamination was relatively localized around the oxidizing sample.
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P.46 Dose Reconstruction
Dosimetric Models of Hematopoietic Sites of Skeleton for Male and Female DA Parshkova*, Chelyabinsk State University
; ?? Shishkina, URCRM, Chelyabinsk, Chelyabinsk State University; EI Tolstykh, URCRM, Chelyabinsk; PA Sharagin, URCRM, Chelyabinsk; MO Degteva, URCRM, Chelyabinsk; MA Smith, PNNL, Richland, Washington
Abstract: The Techa River residents were exposed to radiation as a result of liquid radioactive waste releases of the Mayak PA in 1949-1956. The radioactive releases included long-lived bone-seeking beta-emitter 90Sr, which is the source of chronic internal exposure of the active marrow. Accurate estimates of cumulative internal doses in active marrow play an important role in epidemiological studies of leukemia risk for the exposed population. For bone marrow dosimetry the Techa River Dosimetry System uses dose-conversion factors from specific activity of 90Sr in trabecular and cortical bone volume to accumulated dose rate (DF (AM?TBV) and DF (AM?CBV), respectively).
The aim of the study is to compare dose-factors for adult male and female on the example of thoracic vertebrae and bones of head.
Methods: DFs calculations, which are based on electron-photon transport simulations, require geometrical description of bone shapes and microstructures of hematopoietic sites. Stochastic parametric generator "Trabecula" was used for creation of stylized voxel computational phantoms. The parameters of micro- and macro-structures of hematopoietic sites have been estimated for adult male and female based on published data; DFs calculation was performed by Monte Carlo simulation of electron/photon transport using MCNP6.1.
Results: DFs for female thoracic vertebrae were found to be lower by 8.3% for DF (AM?TBV) and higher by 26.8% for DF (AM?CBV) than for male. It can be explained by sex differences in size of the bones. The sex difference of DFs for head bones didn’t exceed 3%.
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P.47 Internal Dosimetry
Applying of ICP-MS for Individual Dosimetric Control of Plutonium Intake AV Ephimov, Southern Urals Biophysics Institute, Russia
; VR Batalov*, Southern Urals Biophysics Institute, Russia
Abstract: Reducing the limits of detection of plutonium isotopes in human biological samples is necessary to estimate intakes and doses of internal irradiation at a level corresponding to the current limits. If the intake level of slightly soluble plutonium compounds is about ALI, then in a year Pu in the daily amount of urine is expected to be about 0.2 mBq. Since the lower limit of the measurement range of the alpha-spectrometric method is about 1 mBq, personnel working with slightly soluble compounds are not provided with reliable control of the levels of plutonium isotopes intake for at least the first 5 years. To solve this problem a new analysis technique was developed based on measuring Pu by inductively coupled plasma mass spectrometry (ICP-MS). This method is much more sensitive to long-lived isotopes which allowed to reduce the lower limit of the measurement range by more than the order of magnitude compared with spectrometric methods of analysis. The method also makes it possible to determine the isotopic composition of incorporated plutonium which was previously impossible for the isotopes Pu-239 and Pu-240. The developed method of analysis can be used for both estimating current levels of intake of slightly soluble compounds of plutonium and for retrospective dosimetry. The ICP-MS method is a more sensitive, accurate and efficient method for determining Pu-239 in biological samples compared to alpha-spectrometry.
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P.48 Internal Dosimetry
Assessment of Counting Efficiency Depending on the Physical Characteristics of Subject for Whole Body Counting Measurement by Monte Carlo Simulation MS PARK*, Korea Institute of Radiological and Medical Sciences
; WH HA, Korea Institute of Radiological and Medical Sciences; SH PARK, Korea Institute of Radiological and Medical Sciences; YW JIN, Korea Institute of Radiological and Medical Sciences
Abstract: The calibration of whole-body counter is important procedure to obtain the counting efficiency, which is used for calculating the radioactivity retained in the human body. The calibration of whole body counter system utilizes the physical phantoms such as Bottle Manikin Absorber (BOMAB) phantom, but the geometrical discrepancy between the physical phantom and the real body of subject can influence the measurement results in in-vivo measurement. This study aims to assess the dependency of counting efficiencies, considering the age, gender and different size of body by using Monte Carlo simulation. Simulations were performed using several types of computational human phantoms: ICRP reference adult phantoms, UF/NCI family of hybrid phantoms, HDRK phantoms and VIPMAN phantom, and these phantoms were applied to two commercial whole-body counters (stand- and bed-type) replicated by Monte Carlo code (MCNPX 2.7.0). The efficiencies obtained from the computational human phantoms were compared with the counting efficiencies of BOMAB phantom. Averaged relative deviations of efficiencies for adult phantoms are represented from 4.36 to 13.94% in stand-type and 3.91 to 12.81% in bed-type whole-body counter. The discrepancies of efficiencies depending on the age of phantom are within the range of -39.06 to 19.06% and -36.99 to 26.26% in the stand- and bed-type whole-body counters, respectively. The maximum difference of efficiencies due to the gender presents 5.32% in stand-type and 5.37% in bed-type whole-body counter. The influence due to the gender of subject was not crucial in the whole-body measurement compared with other influence factors. The results from this study present that the physical characteristics, especially the age of subject, body volume, and shape of body, can influence the counting efficiencies of whole-body counting measurement and these influence factors would be considered for accurate measurement of internal contamination.
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P.49 Internal Dosimetry
Faster, Sharper, and Open: A New Pipeline for Biota Phantoms D Neville*, Oregon State University
; KA Higley, Oregon State University
Abstract: There are two primary methods for modeling radiation transport in non-humans. The most common treats all organisms as homogeneous ellipsoids made of human soft tissue, while the newer approach creates much more realistic geometry and tissue composition in the form of a voxel model. The voxel model standard gives much more trustworthy dose estimates, but creating them is quite labor intensive and requires the purchase of expensive software. Further, the nature of these voxel models makes it computationally expensive to include fine structures relative to the size of the organism, as all voxels are kept a uniform size. Lastly, it depends on a combination of closed-source code to create an input deck for MCNP, and MCNP itself is access-controlled, limiting the ability to collaborate with the international community. Presented is a new pipeline being developed, which improves upon all of these limitations: minimal labor to segment the organism, dynamic boundaries that allow for fine structures with minimal computational cost, and a fully open-source series of software to allow collaboration and contribution with any institution.
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P.50 Radiation Effects
CANCELLED Association of Single Nucleotide Polymorphisms of Apoptosis and Cell Cycle Control Genes with the Risk of Malignant Neoplasm Development in Chronically Exposed Persons EA Blinova, Ural Scientific and Practical Center of Radiation Medicine, Chelyabinsk
; MA Ianishevskaia*, Ural Scientific and Practical Center of Radiation Medicine, Chelyabinsk; AV Akleyev, Ural Scientific and Practical Center of Radiation Medicine, Chelyabinsk
Abstract: CANCELLED
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P.51 Radiation Effects
Mayak Worker Families and Offspring Database – Source for Studies of Hereditary Effects of Ionizing Radiation TV AZIZOVA, SOUTHERN URALS BIOPHYSICS INSTITUTE
; GV ZHUNTOVA, SOUTHERN URALS BIOPHYSICS INSTITUTE; ES GRIGORYEVA, SOUTHERN URALS BIOPHYSICS INSTITUTE; AA DENISOVA*, SOUTHERN URALS BIOPHYSICS INSTITUTE
Abstract: Ionizing radiation acting upon gonads or germ cells may cause damage to the genetic material and induce mutations leading to genetic diseases (congenital malformations, metabolic disorders, immune deficiency). These diseases may occur over a number of generations. Animal experiments suggest that >1 Gy radiation exposure may induce genetic and epigenetic effects. But human studies have not yet demonstrated increased risks of hereditary effects in offspring of exposed parents. The mission of the Mayak Worker Families and Offspring database (Mayak Family DB) is to develop a raw data source for investigations of reproductive health of Mayak workers, health effects in offspring of exposed individuals, and mechanisms of genomic instability transfer from exposed parents to next generations. The Mayak Family DB is built based on the Medical and Dosimetry database ‘Clinics’ which includes detailed information about each cohort member. As of 31.12.2018 the Mayak Family DB includes 11,030 worker families (with complete information collected) with 16,585 identified offspring. The mean total preconception gonadal doses from external gamma-rays are 0.37±0.61 Gy for males and 0.35±0.50 Gy for females. The DB provides demography and medical information about the workers as well as data on non-radiation factors and availability of biological specimens in the SUBI Human Tissue Repository. The DB is constantly expanded with newly identified families of Mayak workers. The Mayak Family DB containing individual medical data over the whole follow-up period, reproductive health information, non-radiation factor data, individual measured doses from chronic occupational preconception radiation exposure and information on available biological specimens enables analyzing risks of health outcomes in offspring of radiation exposed individuals and investigating mechanisms of various effects, with non-targeted and transgenerational among others, in offspring of exposed parents.
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P.52 Radiation Effects
Analysis of Interrelation Between Lifetime Shortening and Plutonium-239 in Atomic Workers IV Legkikh*, Southern Urals Biophysics Institute
Abstract: The objective of the study was to assess contribution of Pu-239 incorporation to lifetime of Mayak PA workers based on analyzing the relation between lifetime values and Pu-239 incorporation. The analysis involved the cohort of Mayak PA workers hired in 1948-1958 with known Pu-239 body burden; the number of deceased workers was 2343, among them 1739 males and 604 females. Using regression analysis on the basis of Pu-239 incorporation we assessed general lifetime and lifetime from the start of work as well as proportion of individuals who did not survive until standard age. Statistical analysis was performed using the STATISTICA software. It was shown that increase of Pu-239 incorporation in the bodies of deceased workers causes general lifetime shortening for 5.2 years in males and 6.6 years in females, lifetime shortening after start of work made 6.9 years in males and 7.7 years in females. Statistically significant correlation was stated between general lifetime shortening and lifetime shortening after start of work, as well as increase of the proportion of individuals who did not survive until 65 (males) and 70 (females) and the proportion of individuals who did not survive 40 (males) and 45 (females) years after start of work. It was stated that 1 kBq of incorporated Pu-239 causes: decrease of general lifetime in males for 0.32 and lifetime after start of work in males for 0.41 years; in females - decrease for 0.40 and 0.28 years respectively. For 1 kBq of incorporated Pu-239: proportion of males who did not survive until 65 years and proportion of males who did not survive 40 years after start of work increased by 1.44% and 1.87%, in females - 70 and 45 years - by 0.90% and 1.14% respectively. The results obtained give evidence of gender differences in deviations of lifetime values in males and females in relation to Pu-239 incorporation.
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P.53 Radiation Effects
CANCELLED - The Study of the Telomere Length in Chronically Exposed People Ya Krivoshchapova*, Urals Research Center for Radiation Medicine, Chelyabinsk
Abstract: CANCELLED
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P.54 Radiation Effects
Characterization Of MCP-124 and MCP-150 Metal Alloys for Beam Collimation and Radiation Shielding purposes. K Stinson, University of Alabama at Birmingham
; M Maqbool*, University of Alabama at Birmingham
Abstract: Shielding and protection from radiation is important due to the harmful effects of radiation on human body. Over-exposure to radiation is dangerous and can trigger cancer and other late effects in humans. Therefore, various materials are used to protect public, radiation workers and patients from unnecessary exposure to radiation. Those materials are used as collimators and wedges in radiation oncology and radiography and as shielding materials in health physics. Materials which are candidates to be used as collimators and radiation protectors, need to be investigated for their important properties that play role in controlling radiation dose delivery. Lead has been used for radiation shielding and protection applications but it is important to investigate other metal alloys for such applications due to lead hazards. MCP alloys are low melting point alloys used for such applications. These alloys are typically made of a combination of elements with high densities and useful in photon attenuation. This study characterizes the photon interaction in two potential collimating and shielding metallic alloys MCP-124 and MCP-150. The density, atomic number, and composition of the two alloys is calculated and this information is used to determine the Klein-Nishina electronic cross sections, atomic cross sections, Compton scattering cross sections, energy-transfer cross sections, average energy of the recoiled electron, mass energy-transfer coefficient, and mass attenuation coefficient across a range of energy levels. Our results show that both MCP-124 and MCP-150 can be used as good alloys for beam collimation and radiation shielding and protection purposes.
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P.55 Radiation Effects
Estimation of Exposure Dose by Naturally Occurring Radionuclides in Food consumed in Korea JY Kim*, Korea Insttute of Nuclear Safety
; MK Kim, Korea Insttute of Nuclear Safety
Abstract: The intake of food is important internal exposure pathway for naturally occurring radionuclides, especially Po-210. The internal dose can be estimated differently for the same food due to concentrations of naturally occurring radionuclides in foods, cultural and age conditions in each country. In particular, Po-210, which is known to primarily contribute to internal exposures among uranium and thorium series, present in relatively high concentration in seafood. The importance of Po-210 to dietary intake has been pointed out for countries. According to recent statistics, Koreans eat more variety seafood than world average. In order to reduce underestimation of radioactivity concentration and intake, the average food intake (kg per year) of Korean was applied by classifying the food items in the UNSCEAR food group. Particularly, we used the weighted average radioactivity concentration of each food group as a result of the analysis conducted by KINS. In case of Po-210, we compared the reference value of UNSCEAR which is derived from reference concentrations in foods and the results of the research conducted in Korea. In the former case, the dose by Po-210 was 398 microSv per year, 252 microSv per year and 161 microSv per year for infants, children, and adults, respectively, respectively. In the latter case, when the seafood reference value of Po-210 in Korea is 3.7 Bq per kg was applied, the effective dose is 187 microSv per year. And the age-weighted is 216 microSv per year when 5 Bq per kg as the reference value in Korea was applied. Po-210 accounts for over 90 % of the total dose from uranium and thorium series radionuclides, because reference value and effective dose coefficient calculated by considering age (infant, child, adult) intake is larger than other nuclides. Moreover, the reason for the high reference value of seafood in Korean is that the concentrations of Po-210 such as crustaceans and molluscs are relatively higher than fish. The total effective dose from intake of naturally occurring radionuclides was estimated 343 microSv per year, 371 microSv per year for adults and age-weighted, respectively.
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P.56 Radiation Effects
Measurement of Absorbed Dose and Radiation Quality for Low Energy Beta Particle Emitters in Micrometric Sites Using a Wall-less TEPC CO Boyd*, University of Ontario Institute of Technology
; AJ Waker, University of Ontario Institute of Technology; Boyd
Abstract: Tissue Equivalent proportional counters (TEPC) have had success in the field of experimental microdosimetry in measuring absorbed dose and quantifying radiation quality in terms of event-size spectra and average microdosimetric quantities such as the dose-mean lineal energy, y?D (keV/µm). Following serious nuclear reactor accidents, radionuclides can be released to the environment as radioactive particles, ranging from sub-microns to fragments and are termed "hot" particles (HP). Understanding the radiological impact of hot particles likely to be released into the environment by a severe accident from a nuclear power plant or contamination arising from decommissioning or refurbishment of a reactor facility requires both the quantification of absorbed dose and radiation quality as a function of depth in tissue from the hot particle. To achieve this objective we are developing an apparatus based on a wall-less tissue equivalent proportional counter to measure the absorbed dose gradient and radiation quality as a function of distance from a Ni-63 beta source. The results of this work along with Monte-Carlo simulations will be used for the design of a more general system suitable for the assessment of hot particles encountered in nuclear operations. This work will highlight the design of the measurement system and wall-less TEPC and early results from the study of Ni-63.
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P.58 Medical Health Physics
Reducing Variability of Radiation Dose in Computed Tomography: The New Frontier in Patient Safety S Lockerby*, Einstein Healthcare Network
; RK Lee, Einstein Healthcare Network; JY Sun, Einstein Healthcare Network; E Soltycki, Einstein Healthcare Network; T Matalon, Einstein Healthcare Network
Abstract: Although reducing radiation dose in CT examinations is an important goal, also important in the management of radiation dose is ensuring consistency of dose administered for a given type of examination. We have implemented an approach to reducing variance in CT radiation dose by standardizing protocols and implementing software that decreases variance. A multifaceted approach to reducing variance in CT radiation dose was utilized: (1) establishment of the Radiation Dose Optimization Committee, (2) standardization of protocols, and (3) implementation of scanner software. Two periods of data were collected: pre-intervention (January 1, 2013, to July 31, 2014) and post intervention (January 1, 2016, to December 31, 2016). The period from August 1, 2014, to December 31, 2015, represented the time the major interventions were performed. Radiation dose and subsequently calculated variance of radiation dose administered for all CT examinations in the network was tracked using a dose tracking software (Radimetrics.) In addition, specific protocols that represented a cross section of different types of examinations were analyzed: head CT without contrast, chest CT without contrast and abdomen and pelvis with contrast. The Brown-Forsythe test was the statistical approach used to evaluate changes in the spreads of radiation dose pre- and post- intervention for each exam type. We found that the average radiation dose for all CT exams performed during the pre-intervention period (n = 39,314) was 22.3 CTDIvol with a standard deviation of 17.0. The average radiation dose for all CT exams performed during the post intervention period (n = 49,863) was 13.6 CTDIvol with a standard deviation of 9.01. The post intervention variance was significantly decreased (P < .0001). We concluded that a significant decrease in the variability of our network CT radiation dose was achieved as a result of a combination of standardizing protocols across the network and implementation of advanced software that effectively managed radiation dose, all overseen by the Radiation Dose Optimization Committee.
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P.59 Medical Health Physics
State of Radiation Protection Practice by Radiologic Technologists at Saudi Pediatric Hospitals MS Gary*, Alfaisal University
Abstract: Medical radiation protection is best achieved when radiologic technologists are fully aware of its requirements and regulations because they are the front line radiation service providers, particularly at pediatric centers. This project aimed at evaluating Saudi radiologic technologists' knowledge and extent of actual practice. A total of 12 pediatric hospitals in five regions of Saudi Arabia were included. An online survey containing 26 questions was sent via e-mail and WhatsApp to approximately 1,000 radiologic technologists, of which 269 responses were completed (Rates: 61% and 27%, respectively). Radiation protection knowledge gaps among practicing radiologic technologists was at 47%, with varying degrees. The practice gap was greater as a clear majority did not shield sensitive areas or practice uniform ALARA methods. As a result as set of corrective measure were developed. This poster will present the current status of radiation safety practices at Saudi pediatric centers
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P.60 Medical Health Physics
Evaluating Dosimetric Changes Caused By Positional Errors Of The SAVI Applicator Used For Breast Cancer Treatment. A Jammali, Ball State University
; M Maqbool*, University of Alabama at Birmingham
Abstract: Breast cancer is the most frequently detected cancer in women in developed countries. It can be treated with surgery and radiotherapy. Internal radiotherapy as known as Brachytherapy, is the most convenient method to treat breast cancer. The present work reports the use of High Dose-Rate Brachytherapy (HDR) with SAVI applicator to treat breast cancer. The SAVI applicator combines the tissue-sparing dosimetry of interstitial brachytherapy with the single-entry ease of balloon brachytherapy. It is commonly used to deliver radiation to the site of breast lumpectomy post-surgery and this method is called Accelerated Partial Breast Irradiation (APBI). The investigation is done by simulating different positional errors through planning treatment software. The changes are compared with previous patient’s data. A CT scan is sued to interpret or analyze the anisotropy of delivered doses through various geometries. Also the CT is used to make sure that there is no movement of SAVI applicator location that would result in to change the entire treatment planning. Dose volume histogram (DVH) is used to compare the result and evaluate the delivered doses in different organs close to the breast. The maximum dose of skin, chest wall, PTV_Eval for V90, V150, V200 is evaluated according to the NSABP PROTOCOL B-39. The PTV_Eval is the volume that is evaluated for different percentages of the prescribed dose and is defined as the volume of the excision cavity that is expanded uniformly in 1 cm margins from the original tumor bed. V90 which is the volume that is receiving ≥ 90% of the prescribed dose, V150 ≤70 cc of the volume that receives 150% of the prescribed dose, V200 ≤ 20 cc of the volume that is receiving 200% of the prescribed dose, Dose Homogeneity Index (DHI) ≥0.75 and the maximum dose to the chest wall and skin should not exceed 125% of the prescribed dose, to fulfill NSAPB B_39 recommendation.
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P.61 Medical Health Physics
Four-Dimensional Digital Tomosynthesis Based On Visual Respiratory Guidance DS Kim, The Catholic University of Korea
; TS Suh*, The Catholic University of Korea
Abstract: The aim of this research was to introduce and evaluate a respiratory-guided slow gantry rotation 4D digital tomosynthesis (DTS). For each of 10 volunteers, 2 breathing patterns were obtained for 3 minutes, one under free breathing condition and the other with visual respiratory-guidance using an in-house developed respiratory monitoring system based on pressure sensing. Visual guidance was performed using a 4s cycle sine wave with an amplitude corresponding to the average of end- inhalation peaks and end-exhalation valleys from the free-breathing pattern. The scan range was 40 degrees for each simulation, and the frame rate (FR) and gantry rotation speed (GRS) were determined so that one projection per phase should be included. Both acquisition time (AT) and the number of total projections to be acquired (NPA) were calculated. Applying the obtained respiration pattern and the corresponding sequence, virtual projections were acquired under a typical geometry of Varian on-board imager for two virtual phantoms, modified Shepp-Logan (mSL) and XCAT (extended Cardiac-Torso). For the XCAT, two different orientations were considered, anterior-posterior (i.e., coronal) and left-right (i.e., sagittal). Projections were sorted to 10 phases and image reconstruction was made using a modified filtered back-projection. Reconstructed images were compared with the planned breathing data (i.e., ideal situation) by SSIM (Structural Similarity) and NRMSE (Normalized Root-mean-square Error). For each case, simulation with guidance (SwG) showed motion-related artifact reduction compared to that under free-breathing (SuFB). SwG required less NPA but provided slightly higher SSIM and lower NRMSE values in all phantom images than SuFB did. In addition, the distribution of projections per phase was more regular in SwG. Through the proposed respiratory-guided 4D DTS, it is possible to reduce imaging dose while improving image quality.
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P.62 Medical Health Physics
Validation of Isodose Curves for the Airo Mobile CT BR Smiley*, Duke University
; S Kurgatt; T Yoshizumi
Abstract: Manufacturer data is relied upon when initial surveys are conducted on newly installed Computed Tomography (CT) scanners, and it is not common practice to verify the data provided. The Mobius Airo Mobile CT is the first mobile CT device in Duke’s Radiation Oncology department. Due to this, in determining the safety of this device for occupational workers, scatter measurements were taken to determine exposure in air and to verify the validity of the isodose data provided. In order to compare measured data to the manufacturer provided information, the experiment was designed to replicate the manufacturers analysis. Information about the data acquisition was provided by the distributor of the device, Brainlab. The CT settings utilized during the manufacturers data acquisition was 120 kV, 100 mA and 1.92 seconds. To generate scatter, a 32 cm body CT dose index (CTDI) phantom was used and was positioned on the CT table at isocenter. For our data collection, markings were placed at different distances on the floor around the CT scanner to mark where measurements would be taken. Following the manufacturer settings, ion chambers were used to collect measurements, in integral mode, of scattered radiation at the different points around the CT gantry. The average difference between the manufacturer data and the data collected in this experiment was 31 ± 18%. Although the average difference is about 31%, exposure for each scan ranges from 0.01 to 0.1 μGy/mAs and therefore the differences from a safety standpoint are not drastic enough to cause concern for occupational staff. The data acquisition, although modeled after the information provided, is not exact and is responsible for the larger differences in data. With this, the results confirmed the validity of the data provided by the manufacturer and it can be concluded that the experimental and manufacturer data are comparable.
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P.63 Medical Health Physics
Estimation of Patient Release Exposure Rates for Pediatric Patients Receiving I-131 Therapy L Aziz*, Texas A&M University
; SA Dewji, Texas A&M University
Abstract: Papillary, follicular, medullary, and anaplastic are among the major types of thyroid cancers. In regards to therapy options for tumor therapy, in addition to diagnosis for hyperthyroid patients, radioactive iodine-131 therapy proves to be a prevalent mode of treatment. Much work has been simulated and studied in adults to determine patient release dose rates and exposures from I-131 therapy, but little has been studied in pediatric scenarios. Using Monte Carlo radiation transport code to model stylized upright pediatric phantoms, an exposure rate as a function of distance can be determined after I-131 has been administered. This can be then correlated with biokinetics as I-131 metabolized, concentrated in the thyroid gland, and then excreted through the urinary bladder over time, treating each of these three cases as a photon emitting source. The importance of this work is to estimate exposure rates and evaluate the radiation safety of pediatric patients who have received radioactive iodine-131 therapy.
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P.64 Ethics and Radiation Protection
Proposal of Technology Trees for insuring the Qualities of Radiation Safety Program in Korea BH KIM*, KAERI
; WT HWANG, KAERI; JI LEE, KAERI; KM KIM, KIRAMS; CH KIM, Han Yang Univ.; KP KIM, Kyung Hee Univ.; HS LEE, PAL; JW KWON, KINS; SY KIM, RadCore; JI KIM, KHNP RHI
Abstract: Very necessary technologies to insure radiation safety quality for the protection of radiation workers, the pubic and the environment in Korea were classified and categorized into the technology tree format through the task group activity done by one of the special committees of Korea Nuclear Society. With increase of worries and requests for reliability to radiation safety in the Korean public, we prepared so many technologies of radiation protection to be completed in near feature and proposed them as an intermittent plan, to be carried out as part of national projects. Four main categories of radiation safety were as follows; 1) Medical use of radiation, 2) Operation and life-cycle maintenance of accelerator facility, 3) Topics related on the safe management of NORM/TENORM, and 4) Protection of both individuals and environments in normal working conditions as well as in abnormal radiation exposure situations such as radiation accident. The list of contents consisting of 133 technologies which are included in four categories will be shown as in tree structures. We also chose four subjects with priority considering current social needs in Korea as follows; Quality Control and Accuracy Enhancement in Nuclear Medical Imaging, Accelerator Radiation Safety Assessment and its Related Standardization Techniques for Regulatory Purpose, Retrospective Dosimetry System and Risk Evaluation in Abnormal Exposure Situation, and Enhancement of Radiation Emergency Countermeasure Technology.
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P.65 Military Health Physics
Space Applications with Radiation Sources and Detectors, Part 1. A Philatelic Look at Health Physics History. TP Johnston*, NIST
Abstract: This health physics history installment illustrated with postage stamps ventures towards the heavens. On 7 December 1972 this author first visited the NASA complex at Cape Canaveral. The date is memorable since at 12:33 a.m. our family witnessed the launch of Apollo 17 at Cape Canaveral from Launch Complex 39. Apollo 17 was the last mission to land men on the moon and the only night launch. An interesting note: NASA was concerned about and protection measures were initiated with respect to radiation dose. The space radiation environment involved Van Allen belt radiation, solar particle events, cosmic rays, and neutrons. There was also exposure to 147Pm and 3H used for radioluminescent switch tips, control panels, and lighting.
For over 50 years, space nuclear power sources have been successfully deployed to provide electrical power and used as heat sources for satellites and spacecraft. The missions include the Apollo Lunar Surface Experiment Packages; the Pioneer flybys of Jupiter and Saturn; the Viking Mars landers; the Voyager flybys of Jupiter, Saturn, Uranus, and Neptune; the Galileo orbital exploration of Jupiter; the Ulysses solar polar explorer; the Cassini orbital exploration of Saturn; and, most recently, the New Horizons mission to the Pluto/Charon system.
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P.66 Military Health Physics
Space Applications with Radiation Sources and Detectors, Part 2. A Philatelic Look at Health Physics History. TP Johnston*, NIST
Abstract: For the next part of this health physics history segment space craft are portrayed on postage stamps along with diagrams and illustrations. Since 1961, the U.S. has successfully launched 46 nuclear power sources (45 radioisotope thermoelectric generators (RTG) and one nuclear reactor) on 25 space missions along with hundreds of radioisotope heater units (RHU). The SNAP-10A space nuclear reactor power system demonstrated the viability of automatically controlled, liquid-metal-cooled reactors for space applications. The radioisotope thermoelectric generators have enabled some of the most challenging and scientifically exciting missions in human history.
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P.67 Military Health Physics
Ships and Submarines. A Philatelic Look at Health Physics History. TP Johnston*, NIST
Abstract: The author’s story of U.S. nuclear powered vessels: ships and submarines.
The story begins by way of fascination with science, and adventure and enjoyment gained through reading. Introduction to this topic came via discovery of Jules Verne’s Twenty Thousand Leagues Under the Seas: A Tour of the Underwater World. This classic describes Captain Nemos wonderful existence aboard the Nautilus and the undersea adventures capable with an electric powered submarine. The youngster next experienced a close encounter with Nemos Nautilus on 7 December 1972 during a visit to Disneyworld and a ride on Walt Disneys version. This date is memorable since that evening our family witnessed firsthand the night launch of Apollo 17 at Cape Canaveral. Apollo 17 was also the last Apollo mission to land men on the moon. An interesting note: NASA was concerned about, and protection measures were initiated with respect to radiation dose. Not only the cosmic radiation, but also exposure to the 147Pm used to illuminate switches and control panels, and from the 3H (tritium) used for radioluminescent lighting.
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P.68 Works in Progress
Dual PSA Discriminators to Categorize Marginal Events for Optimal Alpha Beta Separation and Improved Quality Metric M Belobradydich, PerkinElmer, Inc.
; R Harazin, PerkinElmer, Inc.; J Sim, PerkinElmer, Inc.; R Troyer*, PerkinElmer, Inc.; B Ward, PerkinElmer, Inc.
Abstract: In unknown samples that may contain a mixture of alpha and beta nuclides, a Pulse Shape Analyzer (PSA) technique is used to evaluate the pulse shape vs. pulse height of scintillation events, categorizing them as alpha (longer event tail) or beta (shorter event tail). Optimizing this process for the least amount of misclassification, or spillover, is desirable because spillover increases the noise or background levels in the opposing spectrum. In pulse shape analysis methods, some events will potentially spillover to the opposing spectrum, particularly those events that are near the discrimination threshold. The introduction of dual PSA discriminators allows a chosen range of these marginal events to remain unclassified and be rejected from both the alpha and beta spectra. This dynamically reduces spillover, resulting in an improved Quality Metric and reduced Minimum Detectable Activity. Additionally, the advent of a PSA Histogram mode significantly reduces the counting time of alpha/beta standards by storing the PSA value for every scintillation event. This eliminates the need to count standards at a series of discrete PSA values to automatically and accurately determine the optimal PSA discriminator settings.
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P.69 Works in Progress
Low Dose Radiation Induces Radioprotective Melanocyte Umbrella And A Latent Hormetic Effect In Danio Rerio SC Gee*, Reed College
; OL Hagen, Reed College; LS Shokat, Reed College; MP Krahenbuhl, Reed College; KL Cerveny, Reed College
Abstract: Hematopoietic stem and progenitor cells (HSPCs) are located in the bone marrow of adult terrestrial mammals, but in the kidney marrow of teleost fish. Little is known about the evolutionary pressures that favored this transition of the hematopoietic niche. In zebrafish, the production of a “melanocyte umbrella” over the hematopoietic niche was recently reported to provide protection from non-ionizing ultraviolet B (UVB) radiation induced DNA damage, suggesting UVB radiation as a selective pressure influencing the niche’s relocation (Kapp et al., 2018). To determine whether ionizing ????-radiation may also have provided pressure to move the HSPC niche to the bone marrow, zebrafish (Danio rerio) 4 days post-fertilization (dpf) were exposed to 200 milligrays (mGy) of ????-radiation for 6 hours. At 1 day post IR (dpIR) and 4 dpIR, the melanocyte umbrella, cell apoptosis, and red blood cell (RBC) population sizes were assayed. At 4 dpIR (9 dpf), zebrafish larvae exhibited a clear increase in melanocyte umbrella density and number of RBCs as compared to non-irradiated controls. Comparisons between numbers of apoptotic dying cells in 1 dpIR and 4 dpIR zebrafish larvae showed that initial levels of cell death dipped below non-irradiated controls but then returned to control levels by 4 dpIR. These results suggest that low dose ????-radiation, in addition to UVB radiation, could have been an evolutionary pressure that influenced the relocation of HSPCs to the bone marrow of terrestrial mammals. Moreover, these results support the hormetic model of radiation dose-response, with implications for health physics policy and standards for medical radiation exposures.
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P.70 Works in Progress
Aqueous Uranium Uptake Using Dextran-graft Polyacrylamide and Kaolinite Clay TA Cabrera*, Clemson University
; VN Bliznyuk, Clemson University; NV Kutsevol, Kiev Shevchenko University; TA DeVol, Clemson University
Abstract: Concentration of uraniume from aqueous media is important in analytical methods for homeland security, groundwater cleanup and mining of uranium from the ocean. Dextran-graft copolymers used in conjunction with kaolinite clay has been evaluated for 233U and 238U removal from pH 4 and 6.5 water and simulated seawater. Polymers of varying dextran concentration D20-PAA, D70-PAA, and D500-PAA and their acidic varieties D20-PAA(c), D70-PAA(c), and D500-PAA(c) were tested to determine the optimal concentration and polymer type for uranium removal. Following batch contact of the polymers with the uranium solutions, kaolinite was added to precipitate the uranium/polymer complex. The uranium that was not removed from solution was quantified using a Quantulus 1220 liquid scintillation counter. A positive correlation between polymer concentration and uptake was found for the standard polymers, with removal of up to 94% using D20-PAA. The acidic varieties of polymer consistently show a negative correlation between polymer concentration and % removal. The effect of using a 45 µm filter after flocculation was determined to increase the uranium removal by 5-20%.
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P.71 Works in Progress
Moving Towards Risk Informing Emergency Preparedness around Commercial Nuclear Power Plants PA Milligan*, US NRC
Abstract: In the early 2000s, the NRC anticipated that future small modular reactor (SMR) and other new technology (ONT) applications would reflect a wide range of potential designs that have smaller source terms than the current fleet of large light water reactors and inherently incorporate EP considerations into the design.
Current EP requirements and guidance, initially developed for large light water reactors and non-power reactors, do not consider advances in designs and safety research and their applications to the future operation of SMRs and ONTs. The NRC is conducting a rulemaking that would amend regulations and develop implementing guidance to create an alternative EP framework for SMRs and ONTs. .
The proposed EP requirements and implementing guidance would adopt a consequence-oriented, risk-informed, performance-based, and technology-inclusive approach. This approach would consider the risks posed by operation of the reactor, and the EP requirements would be commensurate with the risk. This approach includes scaling the EPZ size.
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