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Nevada Test Site Fallout Manuscript date: February 1984 *Los Alamos National Laboratory LAWRENCE LIVERMORE NATIONAL LABORATORY University of California . Livermore, California l 94550 Available from: National Technical Information Service . U.S. Department of Commerce 5285 Port Royal Road l Springfield, VA 22161 . $7.00 per copy . (Microfiche $4.50 )
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NEVADA TEST SITE FALLOUT ATOM RATIOS: Lawrence Livermore National Laboratory Los Alamos National Laboratory The exposure of the population in Utah to external gamma radiation from the fallout from nuclear weapons tests carried out between 1951 and 1958 at the Nevada Test Site (NTS) has been reconstructed from recent measurements of 137Cs and plutonium in soi1.l The fraction of 137Cs in the fallout from NTS events was calculated from the total plutonium and the 240Pu/239Pu ratios measured in the soil, using the values of 0.180 5 0.006 and 0.032 t 0.003 for that ratio in global fallout and NTS fallout, respectively. The total population exposure from NTS events was then calculated on the basis of exposure rates resulting from start-lived radionuclides associated with the 137Cs at the time of deposWhile the 240Pu/23gPu ratio is constant in global fallout, this ratio varies greatly in the fallout from individual events. While the composition of fallout on Utah from NTS events is rather uniform, the Off-Site Radiation Exposure Review Project is currently reconstructing radiation exposures for locations close to NTS where the fallout may be predominantly from one event. Therefore, the authors compiled the pertinent ratios in order to provide information concerning the exposure resulting from any individual event. The plutonium ratios measured at 30 days postshot, shown in Table 1, were compiled from unpublished values in the archives of the Nuclear Chemistry Division of LLNL and INC-11 of LANL. These ratios are pertinent to fallout data. Dates for each event were taken from a publication by the Nevada Operations Office of the Department of Energy.3 This work was funded by the Off-Site Radiation Exposure Review Project.
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TABLE 1. Some NTS Fallout Plutonium Atom Ratios Event Date Ratio Event Date, Ratio Event Date Ratio OPERATION UPSHOT-KNOTHOLE OPERATION PLUMBOB - No analytical data available.
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TABLE 1. Some NTS Fallout Plutonium Atom Ratios (cont.> Event Date Ratio Event Date Ratio OPERATION HARDTACK II OPERATIONS NOUGAT THROUGH BOWLINE
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2. :,ti;X.Eicks, "Results of CakUlatiOnS Of External Gamma Radiation Exposure ut and the Related Radionuclide Compositions," Lawrence rations Nougat through Bowline, 1962-1968 d States Nuclear Tests," July 1945 through December 1982,