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Title: 137 Cs Activities and 135 Cs/ 137 Cs Isotopic Ratios from Soils at Idaho National Laboratory: A Case Study for Contaminant Source Attribution in the Vicinity of Nuclear Facilities

Radiometric and mass spectrometric analyses of Cs contamination in the environment can reveal the location of Cs emission sources, release mechanisms, modes of transport, prediction of future contamination migration, and attribution of contamination to specific generator(s) and/or process(es). The Subsurface Disposal Area (SDA) at Idaho National Laboratory (INL) represents a complicated case study for demonstrating the current capabilities and limitations to environmental Cs analyses. 137Cs distribution patterns, 135Cs/137Cs isotope ratios, known Cs chemistry at this site, and historical records enable narrowing the list of possible emission sources and release events to a single source and event, with the SDA identified as the emission source and flood transport of material from within Pit 9 and Trench 48 as the primary release event. These data combined allow refining the possible number of waste generators from dozens to a single generator, with INL on-site research and reactor programs identified as the most likely waste generator. A discussion on the ultimate limitations to the information that 135Cs/137Cs ratios alone can provide is presented and includes (1) uncertainties in the exact date of the fission event and (2) possibility of mixing between different Cs source terms (including nuclear weapons fallout and a source of interest).
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [2]
  1. Washington State Univ., Pullman, WA (United States). Dept. of Chemistry; Idaho National Lab. (INL), Idaho Falls, ID (United States)
  2. Idaho National Lab. (INL), Idaho Falls, ID (United States)
  3. Washington State Univ., Pullman, WA (United States). Dept. of Chemistry
Publication Date:
OSTI Identifier:
1182692
Report Number(s):
INL/JOU--14-31778
Journal ID: ISSN 0013-936X; TRN: US1500196
DOE Contract Number:
AC07-05ID14517; 2012-DN-130-NF0001-02
Resource Type:
Journal Article
Resource Relation:
Journal Name: Environmental Science and Technology; Journal Volume: 49; Journal Issue: 5
Publisher:
American Chemical Society (ACS)
Research Org:
Idaho National Laboratory (INL), Idaho Falls, ID (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; IDAHO NATIONAL LABORATORY; CESIUM 137; CESIUM 135; MASS SPECTROSCOPY; ISOTOPE RATIO; FALLOUT; FLOODS; FORECASTING; MIXING; CONTAMINATION; FISSION; SOILS; RADIONUCLIDE MIGRATION; RADIOACTIVE WASTES; SOURCE TERMS; SPATIAL DISTRIBUTION 135Cs/137Cs; CESIUM-137; NUCLEAR FORENSICS; SDA