are a consequence of using pseudovector TTN coupling; with pseudoscalar coupling they would be replaced by the corresponding magnetic form factors G M " 5

The purpose of this study was to evaluate and provide insights related to the influence of the intake of stable isotopes of carbon and iodine on the committed doses due to the ingestion of (14)C and (129)I. This was accomplished through the application of two different computational approaches. The first was based on the assumption that ground (drinking) water was the only source of intake of (14)C and (129)I, as well as stable carbon and stable iodine. In the second, the intake of (14)C and (129)I was still assumed to be restricted to that in the ground (drinking) water, but the intake of stable carbon and stable iodine was expanded to include that in other components of the diet. The doses were estimated using either a conversion formula or the applicable dose coefficients in Federal Guidance Reports No. 11 and No. 13. Serving as input for the analyses was the estimated maximum concentrations of (14)C or (129)I that would be present in the ground water due to potential releases from the proposed Yucca Mountain high-level radioactive waste repository during the first 10,000 y after closure. The estimated contributions of stable carbon and iodine through the consumption of ground water were based on analyses of samples collected in the Amargosa Valley, NV. The contributions through dietary intake were based on surveys conducted in the United States. Based on the accompanying analyses, it was noted that stable isotope intake has a significant effect on the estimated doses due to the intake of radioactive isotopes of the same element. While this is a well-known fact, this observation has international implications in terms of dose estimates for key radionuclides, such as (14)C and (129)I, a primary reason being the wide variations in the intakes of stable carbon and iodine in various countries. For this reason, analysts planning to apply the dose coefficients developed by the International Commission on Radiological Protection (ICRP) should either confirm that the average total intake in their country of stable isotope(s) of the radioactive isotope being evaluated is in reasonable agreement with the value assumed by the ICRP or suitably modify the ICRP dose coefficients to account for any differences. If such a procedure is to be implemented, there is a need for periodic updates of the dietary intakes of various stable elements in countries throughout the world. The importance of this is documented by recent surveys in Asia that revealed that their average total daily intake of stable iodine was less than half of the ICRP value for Reference Man. In this case, application of the ICRP dose coefficients, without modification, would underestimate the dose due to ingested (129)I by a factor of more than two. A related situation exists in the United States where the latest surveys indicate that the daily intake of stable iodine is 75% of the ICRP value.

C and Ra are two of the radionuclides that have either been identified as being potentially significant in terms of releases from the proposed Yucca Mountain high-level radioactive waste repository, or are specifically cited for consideration and evaluation in the regulations promulgated by the U.S. Nuclear Regulatory Commission. The purpose of this study was to estimate the concentrations and associated doses for these two radionuclides, if released under conditions of a scenario assumed to apply to a repository containing some of the features of the one proposed at Yucca Mountain, NV, and to compare these estimates to the regulatory limits for that facility. For C, the postulated condition was that an annual fractional release of 10 of its total remaining inventory occurs beginning at 10,000 y after repository closure. For Ra, the same fractional release rate was assumed, but in this case it was presumed to occur when the Ra inventory was projected to reach a maximum at more than 10 y after repository closure. The estimated concentrations and doses were, in turn, compared to the concentration limit, specified in the Ground Water Protection Standards (GWPSs) in the case of Ra, or derived, in the case of C, on the basis of the regulatory dose rate limit. Due to the small inventory of C in the waste, and its short half-life relative to the performance period evaluated, its estimated concentration in the ground water would be slightly more than 4% of the derived GWPS. Due to the relatively small initial inventory of Th, the precursor of Ra, and the correspondingly small quantities of higher atomic number actinides that could, through decay, produce additional quantities of Th, its estimated concentration in the ground water would be less than 3% of the GWPS, leaving the remaining portion of the limit for potential contributions from Ra. At the same time, however, it must be recognized that, in this case, the regulations require that any contributions of naturally occurring Ra and Ra already present in the ground water must be included in the determination of compliance. If this is done, the total concentration of Ra, combined with the naturally occurring concentration of Ra, would be about 10.5% of the limit. In a similar manner, the committed doses due to the annual consumption of each of these two radionuclides in ground water and food, produced in the local biosphere, were evaluated in terms of the Individual Protection Standard (IPS). Based on these analyses, the estimated effective dose for C, using the coefficients in Federal Guidance Report (FGR) No. 13, was 4.15 muSv y, less than 3% of the IPS. For Ra, the comparable estimate at the time of maximum inventory, excluding in this case the contributions from naturally occurring Ra and Ra, was 7.39 muSv y, representing about 5% of the IPS. Based on the value assumed for the fractional release rate (10 y), it was concluded that neither C nor Ra will be significant in terms of either the applicable GWPS or the IPS. While it was recognized that, due to the time spa...

Over the century that radioactive materials have been mined, processed, produced, and utilized, many sites across the United States have become contaminated. Such sites include bases and installations of the Department of Defense, weapons production and research facilities of the Department of Energy, properties under the authority of other Federal agencies, privately-owned and governmental facilities that are licensed by the Nuclear Regulatory Commission and its Agreement States, and sites licensed by or the responsibility of states. This review reports on aspects of work by the Environmental Protection Agency, the Department of Defense, the Department of Energy, the Nuclear Regulatory Commission, and others to identify sites contaminated with radioactive materials. It also describes the principal programs that have been instituted to deal with them.

Directional correlation measurements have been made for y-transitions in "As following the decay of 11.30 h "Ge using two Ge(Li) detectors. Using the method of Chow et al., mixing ratios of y-transitions and the spins of seven levels have been deduced assuming only a ground-state spin of 4. Levels for which spins were deduced are 216(s), 264(*), 475(3), 632(f), 1189(g), 1458@) and 1528(#) keV. E RADIOACTIVITY "Ge [from 76Ge(n, r)]; measured n(6). "As levels deduced J, y mixing ratios.