External Dose to Recovery Teams Following a Wide-area Nuclear or Radiological Release Event

Abstract

The common radionuclide ¹³⁷Cs is a gamma-ray source term for nuclear reactor accidents, nuclear detonations, and potential radionuclide dispersal devices. For wide-area contamination events, one remediation option integrates water washing activities with on-site treatment of water for its immediate reuse. This remediation option includes washing building and roadways via firehose, collecting the wash water, and passing the contaminated water through chemical filtration beds. The primary objective of this study was to quantify the dose incurred to workers performing a remediation recovery effort for roadways and buildings following a wide-area release event. MicroShield® was employed to calculate the dose to workers at the roadway level and to calculate total dose rates while performing washing activities. This study finds that for a realistic contamination scenario for a wide area of a large urban environment, decontamination crews would be subjected to <220 μSv per person, much less than the 50,000 μSv limit for occupational dose. By extrapolation, one decontamination team of 48 people could continue washing operations on a total of 2.8 km² before reaching their incurred annual dose limits. Though it is unrealistic to assign one team that entire area, we can conclude external dose will not limit worker deployment given the range of contamination levels adopted in this study.