TUE-F - Accelerator Health Physics Topical Session Tuesday 09/29/20 2:00 PM - 5:00 PM
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| Chair(s): Bob May, Matthew Quinn
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TUE-F.1
2:00 PM Review of Radiological Controls Applied to TRU and Non -TRU Alpha Emitters Experiments at SLAC MT Torres*, SLAC National Accelerator Laboratory
Abstract: SLAC conducts about 50 radioactive experiments (RAM) a year at SSRL. SLAC is conducting an evaluation on the SSRL RAM experiments that contains TRU radionuclides and non-TRU alpha emitters. Radiological controls are applied based on the form of the matrix (e.g. solid, liquid, powder), type of radionuclides and activities of the samples. SLAC is reviewing the existent radiological controls applied to TRU samples and non TRU alpha emitters and is using a graded approach to evaluate if relief from certain radiological controls such as Continuous Air Monitoring (CAM) can be applied without compromising safety and gain efficiency when providing radiological coverage to the stakeholders. A benchmark was conducted to similar facilities to gain feedback and knowledge of their operations.
ACKNOWLEDGEMENTS. This work is supported by Department of Energy Contract DE-AC02-76SF00515
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TUE-F.2
2:30 PM Low-level Environmental Radiation Monitoring at CEBAF P. Degtiarenko*, Jefferson Lab
; V. Popov, Jefferson Lab; M. Washington, Jefferson Lab
Abstract: Continuous Electron Beam Accelerator Facility at Jefferson Lab operates in the middle of dense urban development in Newport News, VA. The distance from the potential sources of neutron and photon radiation at CEBAF to the site boundary could be as short as 90-100 meters. Major contributors to the environmental radiation at CEBAF are the roofs of the semi-underground Experimental Halls designed for the experiments in which high energy (up to 12 GeV) and high power (up to 800 kW) electron beams interact with fixed targets. Energetic neutrons and photons are capable of penetrating the roofs, contributing to the environmental dose rates at the boundary. Satisfying strict limits on maximum allowable accumulated dose at the site boundary justifies implementation of the state-of-the art monitoring system suitable for long-term monitoring of neutron and photon environmental radiation. The requirements include very high sensitivity and stability of the neutron and photon detectors, sufficient to distinguish between the regular environmental radiation background and the contributions from the CEBAF operations. The report will overview the 25-year history of the monitoring system, describe the system's development and implementation, current operation experience, and plans for the future.
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TUE-F.3
3:00 PM Accelerator Production of Mo-99 Using Mo-100 TH Mohaupt*, NorthStar Medical Radioisotopes, LLC
Abstract: Tc-99m is an essential radionuclide for nearly 45,000 diagnostic nuclear medicine tests in the U.S. each day. Its daily production depends on Mo-99, which must be replenished bi-weekly due to Mo-99’s 2.75 day half-life. Mo-99 currently supplied from uranium depends on overseas nuclear reactors that average 50 years old. Their age and shipment uncertainties make availability of Mo-99 fragile and subject to severe shortages. The U.S. has one domestic, FDA-approved supplier that produces Mo-99 by irradiation Mo-98 in a nuclear reactor. Another process that will irradiate Mo-100 with x-rays will produce Mo-99 by 2021. Accelerator produced Mo-99 has several advantages over that produced by reactors, including a redundant supply and an ability to adjust irradiation timing to meet radiopharmacy demands.
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TUE-F.
3:30 PM BREAK
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TUE-F.4
3:45 PM Developing Robust Radiation Safety Program for Pre-existing and New Accelerators F Boateng*, National Institute of Standards and Technology
; J Zometsky, National Institute of Standards and Technology; M Spady, National Institute of Standards and Technology; M Mejias, National Institute of Standards and Technology; Fr Bpateng
Abstract: Having a wide range of particle accelerator (PA) facilities for research, development, and calibrations which includes a medical/clinical linear accelerator, a medical-industrial accelerator, a Van de Graaff, a Synchrotron Ultraviolet Radiation Facility, as well as neutron generators (deuterium-deuterium, and deuterium-tritium generators) in one campus brings great operational health physics experience and excitement coupled with unique challenges. The challenge arises when the program lacks updated technical documents as a guide to implement radiological safety requirements. Although the National Institute of Standards and Technology (NIST) PA facilities have been active since 1964, the Radiation Safety Office/Division, in collaboration with NIST researchers, is seeking to improve the thoroughness of the radiation safety policies and procedures to support the existing equipment as well as new state of art equipment. Our goal is to develop a more robust written radiation safety program for such a diverse set of existing and new PA facilities. Thorough program assessments were performed, including a self-assessment by NIST radiation safety staff and a Subject Matter Expert assessment to ensure accelerator operations and health physics activities were in line with industry standards. This presentation will focus on the lessons learned and strategies employed by the NIST in developing a robust written radiation safety program for PA facilities.
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TUE-F.5
4:15 PM Development of a Release Protocol for Potentially Activated Oil AJ Stavola*, JLab
Abstract: The Thomas Jefferson National Accelerator Facility (TJNAF) has developed a robust protocol for analyzing potentially activated oil for unrestricted release from radiological controls. This protocol can be beneficial for releasing lubricants from vacuum pumps, compressors, and other systems installed near high-power accelerator beam lines and target chambers. TJNAF evaluated the potential dose consequence from credible and low probability exposure scenarios represented by oil incineration and also landfill burial following oil solidification. For conservatism, and due to the ease of measurement, gamma-emitting radionuclides were assigned a release limit equal to the United States Environmental Protection Agency drinking water standards, which were then set as the required minimum detectable concentrations. From the derived exposure scenarios, a release limit of 100 dpm ml-1 was determined to be a reasonably conservative value for tritium minimum detectable concentrations. A significant data set was compiled for the extraction of tritium using a RADDEC™ Pyrolyser and subsequent counting with a Liquid Scintillation Counter (LSC). Tritium recovery, reagent blank, and cleanup measurement distributions were utilized in development of a routine analytical protocol for oil samples taken from within the accelerator enclosure. A Site Specific Evaluation Program was initiated with the United States Department of Energy’s Radiological and Environmental Sciences Laboratory in which blind, tritium-labeled toluene oil samples were analyzed. The samples were provided with activity levels at or near the release limit to ensure the method provides adequate sensitivity. Additional samples were provided at higher activity levels to test the measurement bias. In all cases, the measurement method positively identified 3H greater than background levels, which would lead to the appropriate decision of non-release. This presentation will focus on the methods and analytical considerations employed by TJNAF in development of this release protocol.
*This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177
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TUE-F.
5:00 PM Accelerator Health Physics Business Meeting
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