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Title: Environmental radiological studies conducted during 1986 in the vicinity of the Rancho Seco Nuclear Power Generating Station

Technical Report ·
DOI:https://doi.org/10.2172/6522203· OSTI ID:6522203

This report summarizes the information compiled in 1986 for our assessment of the environmental impact of radionuclides discharged with aqueous releases from the Rancho Seco Nuclear Power Generating Plant. In October 1984, a liquid-effluent control program was initiated that significantly reduced the quantities of radionuclides discharged with liquid waste from the plant. However, results from our sampling program in 1986 indicate that previously discharged radionuclides persist in the downstream environment and are found in many aquatic dietary components although at concentrations much lower than those measured in 1984 and 1985. The greatly reduced activities in the dietary components from the aquatic environment attest to the effectiveness of the liquid-effluent control program. Concentrations in the flesh of fish from the creeks have decreased over time and with distance from the plant outfall. The mean concentration of /sup 137/Cs in fish collected from Laguna Creek at locations more than 7.5 km from Rancho Seco is now comparable to the concentration determined in fresh-water fish randomly selected from Chicago, Illinois, markets. By August 1986, the mean concentration of /sup 137/Cs in the flesh of bluegill had fallen to 7% of the concentration measured in fish from comparable locations in 1984 and was 30% of the mean concentration measured in these fish during August 1985. Stable potassium in the water plays a major role in the accumulation of /sup 137/Cs by fish. Concentrations of /sup 137/Cs in the surface sections of creek sediments also declined between the end of 1984 and 1986 with an effective half-life of approximately 2 y. Surface soils collected around a perimeter 11 km from Rancho Seco and from ranchlands closer to the plant showed only concentrations of /sup 137/Cs originating from global fallout. Soils previously irrigated with Clay Creek water retain levels of both /sup 134/Cs and /sup 137/Cs.

Research Organization:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
6522203
Report Number(s):
UCID-20963-Pt.1; ON: DE87010945
Resource Relation:
Other Information: Portions of this document are illegible in microfiche products. Original copy available until stock is exhausted
Country of Publication:
United States
Language:
English