THAM-D - Contemporary Health Physics Topics Orange A 10:00 - 11:15
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| Chair(s): Jeffrey Lively, Wayne Gaul
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THAM-D.1
10:00 A Conceptual Approach to the Remediation of Wide-Area Radioactive Contamination SY Chen*, Illinois Inst. of Technology
Abstract: In addressing the wide-area radioactive contamination such as caused by a large scale nuclear event the effort toward long-term recovery could be particularly challenging. Thus prioritizing the cleanup effort must rely on a strategy based on optimization as advocated by the National Council on Radiation Protection and Measurements (NCRP) in its Report 175, Decision Making for Late-Phase Recovery from Major Nuclear or Radiological Events. Central to the issue is how to formulate a proper response to the potentially vast radioactive contamination in terms of remediation of land and the related issues such as waste management. Key among the recommendations is the development of an adaptive and responsive radiological cleanup strategy. This paper presents a practical approach toward optimization by incorporating collective dose in radiological assessment into remediation decision making. Toward this end the affected region can be viewed as a mosaic consisting of various population zones each representing an area sharing certain common attributes. The examples may include school yards, municipal centers, public parks, major traffic corridors, residential zones, etc. with varying contamination levels. The strategy is to focus on remediation of the most urgent areas in the short term. The process will be operated iteratively so that both the collective doses and individual doses can be reduced gradually and cost effectively in the long term. This approach deviates from the conventional cleanup methods where the radiological considerations are based solely on meeting the individual cleanup criteria. The proposed approach offers a holistic and rational basis with sufficient flexibility to address cleanup of a region affected by wide-area contamination.
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THAM-D.2
10:15 Scanning Spectroscopy v. Randomized Discrete Soil Samples -- A Case Study In Surface Soil Characterization Data Quality JW Lively*, Wood E&IS
; RG Posner, Wood E&IS; AR Jones, Wood E&IS
Abstract: Grab soil samples analyzed by an accredited analytical laboratory have been viewed as the gold standard for measuring and reporting radionuclide concentrations in soil. However, radionuclides introduced by humans are rarely homogeneously distributed in soils. This heterogeneity results in considerable sampling error, which is often the single largest contributor to the overall uncertainty in characterization, remedial action, and Final Status Survey (FSS) decisions. The various controls employed by laboratories to mitigate measurement uncertainties simply cannot control for the Achilles heel of grab samples the heterogeneous distribution of radionuclide concentrations in soil. To counter this weakness, radiometric surface scan surveys are relied upon as a tell-tale indicator of in situ heterogeneity. However, gamma scan surveys are commonly viewed as qualitative measures or, at best, semi-quantitative measures, due to inherent uncertainties related to gross gamma detection. Advances in field-deployable gamma-scanning instrumentation address many of the uncertainties associated with traditional gross gamma scans and challenge long-held paradigms about the quality of data that can be obtained with scan surveys. A recent FSS was designed to collect three independent measures of the residual radioactivity concentration within the same survey unit: a) laboratory analysis of surface soil grab samples; b) five-minute static in-situ spectral measurements collocated with the soil samples; and c) a surface gamma spectroscopy scan survey. The comparative assessment of the resulting data sets provides convincing evidence that the direct measurement of the radioactivity concentration in near surface soil using instrumentation equipped with scanning spectroscopy is as good or better than that achieved by laboratory analysis of surface soil grab samples.
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THAM-D.3
10:30 Lessons Learned from the Development of a Web-Based System for Managing Gamma Scan Data M Witmer*, Jacobs
; M Brown, Jacobs; T Mason, Jacobs; J Hackett, Jacobs
Abstract: The collection and evaluation of gamma scanning data is an integral part of characterization and remediation activities for radiological sites. The development of a web-based data processing tool using geographical information system software provides users with an accurate and efficient method of processing and managing gamma scan data with either onsite or offsite resources. Users can upload data, define comparison criteria, calculate statistical parameters such as z-scores and monitor performance requirements such as scan speed and coverage for the entire data set or specific subsets of the data. Data are visually presented on the systems graphical interface and numerical indices can be applied to understand the distribution of the data. Data sets are archived within the system and can be managed by site, project, or program. The initial workflow design considers the flexibility needed for processing gamma scan data sets of varying complexity. Additional design considerations for the tool include incorporating instrument quality control data, application of background reference areas to survey data, and internal and external access to data and maps. This presentation provides an overview of the development of a web-based system and lessons learned from an operational health physics perspective.
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THAM-D.4
10:45 IPCM12 Radon Enhancements SD Lamb*, Thermo Fisher Scientific
; Lamb
Abstract: False positive nuisance alarms caused by radon have presented a health physics challenge since the introduction of Alpha/Beta Personnel Contamination monitors. Such nuisance alarms result in reduced productivity, extra health physicist involvement/investigation and lower user confidence in the instrument.
The improvements recently implemented into the IPCM12 result in a significantly better, highly accurate, identification of system counts due to radon that reliably differentiate system counts due to actual alpha or beta contamination. These improvements result in increased worker productivity and reduced operating costs while maintaining proper radiation contamination controls.
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THAM-D.6
11:00 Discussions on Radiation Protection Design under Accident Condition of China PWR XX WANG*, China Nuclear Power Engineering Co. Ltd
; W YOU; AJ MI; YW MAO
Abstract: The public pay more attention to the safety of nuclear power plant after Fukushima accident, and the designer and reviewer of NPP also think about how to deal with different kinds of accidents effectively. The latest safety requirements and standards also mention to the radiation protection design under accident condition. This article descript the current rules, requirements, and consideration of radiation protection design in China PWR, also discuss the challenge in radiation protection design under accident condition.
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