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Title: Evaluation of exposure pathways to man from disposal of radioactive materials into sanitary sewer systems

Technical Report ·
DOI:https://doi.org/10.2172/10153083· OSTI ID:10153083

In accordance with 10 CFR 20, the US Nuclear Regulatory Commission (NRC) regulates licensees` discharges of small quantities of radioactive materials into sanitary sewer systems. This generic study was initiated to examine the potential radiological hazard to the public resulting from exposure to radionuclides in sewage sludge during its treatment and disposal. Eleven scenarios were developed to characterize potential exposures to radioactive materials during sewer system operations and sewage sludge treatment and disposal activities and during the extended time frame following sewage sludge disposal. Two sets of deterministic dose calculations were performed; one to evaluate potential doses based on the radionuclides and quantities associated with documented case histories of sewer system contamination and a second, somewhat more conservative set, based on theoretical discharges at the maximum allowable levels for a more comprehensive list of 63 radionuclides. The results of the stochastic uncertainty and sensitivity analysis were also used to develop a collective dose estimate. The collective doses for the various radionuclides and scenarios range from 0.4 person-rem for {sup 137}Cs in Scenario No. 5 (sludge incinerator effluent) to 420 person-rem for {sup 137}Cs in Scenario No. 3 (sewage treatment plant liquid effluent). None of the 22 scenario/radionuclide combinations considered have collective doses greater than 1000 person-rem/yr. However, the total collective dose from these 22 combinations was found to be about 2100 person-rem.

Research Organization:
US Nuclear Regulatory Commission (NRC), Washington, DC (United States). Div. of Regulatory Applications; Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Organization:
Nuclear Regulatory Commission, Washington, DC (United States)
DOE Contract Number:
AC06-76RL01830
OSTI ID:
10153083
Report Number(s):
NUREG/CR-5814; PNL-7892; ON: TI92015758
Resource Relation:
Other Information: PBD: May 1992
Country of Publication:
United States
Language:
English