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Title: Radiological Assessment for the Removal of Legacy BPA Power Lines that Cross the Hanford Site

This paper discusses some radiological field monitoring and assessment methods used to assess the components of an old electrical power transmission line that ran across the Hanford Site between the production reactors area (100 Area) and the chemical processing area (200 Area). This task was complicated by the presence of radon daughters -- both beta and alpha emitters -- residing on the surfaces, particularly on the surfaces of weathered metals and metals that had been electrically-charged. In many cases, these activities were high compared to the DOE Surface Contamination Guidelines, which were used as guides for the assessment. These methods included the use of the Toulmin model of argument, represented using Toulmin diagrams, to represent the combined force of several strands of evidences, rather than a single measurement of activity, to demonstrate beyond a reasonable doubt that no or very little Hanford activity was present and mixed with the natural activity. A number of forms of evidence were used: the overall chance of Hanford contamination; measurements of removable activity, beta and alpha; 1-minute scaler counts of total surface activity, beta and alpha, using "background makers"; the beta activity to alpha activity ratios; measured contamination on nearby components; NaI gamma spectralmore » measurements to compare uncontaminated and potentially-contaminated spectra, as well as measurements for the sentinel radionuclides, Am- 241 and Cs-137 on conducting wire; comparative statistical analyses; and in-situ measurements of alpha spectra on conducting wire showing that the alpha activity was natural Po-210, as well as to compare uncontaminated and potentially-contaminated spectra.« less
Authors:
 [1] ;  [1]
  1. Mission Support Alliance, Richland, WA (United States)
Publication Date:
OSTI Identifier:
1105959
Report Number(s):
HNF-56300-FP-Rev0-Draft
TRN: US1400395
DOE Contract Number:
DE-AC06-09RL14728
Resource Type:
Conference
Resource Relation:
Conference: WM2014 Waste Management Symposia, Phoenix, AZ (United States), 2-6 Mar 2014; Related Information: Number 14039
Research Org:
Hanford Site (HNF), Richland, WA (United States); Mission Support Alliance, Richland, WA (United States)
Sponsoring Org:
USDOE Office of Environmental Management (EM)
Country of Publication:
United States
Language:
English
Subject:
24 POWER TRANSMISSION AND DISTRIBUTION; 61 RADIATION PROTECTION AND DOSIMETRY