Laboratory and field studies related to the hydrologic resources management program. Annual progress report, October 1, 1995--September 30, 1995

In this report we describe the work done at Los Alamos National Laboratory in FY 1995 for the Hydrologic Resources Management Program funded by the US Department of Energy/Nevada Operations office. Budgetary cuts have required us to scale back our activities, particularly field work at the Nevada Test Site. We have collaborated with a number of government agencies and universities in work related to radionuclide migration through geologic media. In cooperation with Lawrence Livermore National Laboratory, we have demonstrated the utility of high-sensitivity gamma logging and have successfully improved the design of a bailer routinely used for water sampling. We analyzed a suite of side-wall samples from the BASEBALL drill-back and have interpreted the distribution pattern of test-related radionuclides. Though heterogeneously distributed, they show a general separation of volatile and refractory fractions. The distribution pattern suggests that there has been little movement of radioactive material within this cavity, which is 13 years old and below the static water level. This characterization of the BASEBALL cavity/chimney complex may have important implications for radionuclide migration elsewhere at the Nevada Test Site