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Title: Environmental levels of radioactivity in the vicinity of the Lawrence Livermore Laboratory. 1973 annual report

Technical Report ·
DOI:https://doi.org/10.2172/4313971· OSTI ID:4313971

The Lawrence Livermore Laboratory continuously monitors the levels of radioactivity within the Livermore Valley and Site 300. Results of analyses perfomned during 1973 for gross radioactivity and for specific radionuclides of interest in a variety of environmental samples are presented. In all cases, the levels of activity observed during 1973 were found to be below the appropriate concentration guide values in AE C Manual Chapter 0524. Particulate air filters showed gross beta activities lower than those observed during 1972, reflecting a reduction in global fallout in the atmosphere. Gamma spectral measurements on Laboratory perimeter air filters also showed lower activities of global fallout gamma emitters. These perimeter air samples were analyzed for /sup 239/Pu, /sup 236/Pu /sup 90/Sr, /sup 235/U, and /sup 238/U. With the ex ception of one sampling location, the annual average /sup 239/Pu concentration was 1.3 x 10/sup - 17/ mu Ci/ml, typical of global fallout. Air samples taken within Site 300 were analyzed for uranium. These analyses showed a lower than normal ratio of /sup 235/U//sup 238/U. This is due to depleted'' uranium (uranium which is specially processed to lower the /sup 235/U content) used at the Site. Airborne uranium concentrations were well below the standards set by the AEC. Soil samples collected in the off-site vicinity of LLL perimeter boundaries and at Site 300 were analyzed for plutonium, uranium, and gamma emitting radionuclides. Traces of plutonium above global background levels were detected in two off-site samples near the east perimeter of the Laboratory. Sediment samples collected in surface drainage pathways from LLL showed that the plutonium in these sediments was in the same range observed in soil samples collected in the Livermore Valley. Site 300 soil samples indicate depleted levels of /sup 235/U near firing bunkers, but /sup 235/U//sup 236/U rat ios approach that of natural uranium at site perimeters. These data indicate no apparent change from that observed in 1972. Water samples collected within the Livermore Valley exhibited normal background gross beta and tritium activities. Gamma spectral analyses of vegetation samples revealed no gamma-emitting radionuclides other than those present naturally or in global fallout. The vegetation samples collected in areas generally downwind from the Livermore Laboratory revealed tritium activities 10 to 100 times higher than those collected in areas where the Laboratory's contribution should be minimal. However, if the vegetation were a regular pant of one's diet, the annual whole body radiation dose from tritium would be less than 1 mrem. The off- site radiation exposure rates measured by thermoluminescent dosimeters were in the range to be expected from the naturally occurring radionuclides in the soil and from local cosmic radiation. Assessment of the radiation doses to an individual from the observed environmental activities listed indicates the contribution from antificially produced radionuclides is small in comparison with the approximately 100 mrem/y dose received from natural sources. (auth)

Research Organization:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
NSA Number:
NSA-29-029332
OSTI ID:
4313971
Report Number(s):
UCRL-51547
Resource Relation:
Other Information: Orig. Receipt Date: 30-JUN-74
Country of Publication:
United States
Language:
English