A history of the early use of the Monte Carlo method is presented.

The US Department of Energy has established an organizational structure that assures the quality of key data identified as being important to the licensing of a nuclear waste repository by the US Nuclear Regulatory Commission. The Materials Characterization Center collects and/or develops the test methods needed to obtain the data, and acts as a clearinghouse for all data obtained by the methods, regardless of source. The Materials Review Board reviews both test methods and test data submitted to it, and approves them if they meet the rigorous criteria and standards that have been established. The appearance of test methods and test data in the Nuclear Waste Materials Handbook is evidence that the material has undergone intensive review and can be used with confidence within the bounds of the application specified. The principal use of the Handbook is in the repository licensing process.

During 1984 and 1985 the SLC alignment group established and measured a system of elevation benchmarks (BM's) over the whole of the SLAC site, ranging from the injector area to the NGS horizontal control point (surface monument) AA on the hill to the east of the collider hall outside the radiation fence. Precise elevations are needed in general for survey, alignment, placement, and monitoring of SLC tunnels and components. In particular, precise elevations of the survey instruments, mounted over penetrations to the tunnels and over the horizontal control points, are needed for the reductions of measured distances on the surface. Precise elevations were also needed at several other locations, like sector 1, 10, 19, and 30 along the LINAC (for the Global Positioning System measurements), outside of the IR 8 access to PEP (to connect the run from the SLC Master Benchmark R306 close to LINAC station 100 + 00 through the PEP SIT tunnel), and at the south-west adit to the SLC tunnel (to connect the BSY run). Permanent benchmarks were, therefore, installed close to these locations. To minimize errors and simplify re-leveling, turning points were also permanently installed. Figure 1 shows the locations of the elevation benchmark east …

To study the reaction of water vapor with uranium, we have exposed clean liquid uranium surfaces to H/sub 2/O under UHV conditions. We have measured the surface concentration of oxygen as a function of exposure, and determined the maximum attainable surface oxygen concentration X/sub 0//sup s/ as a function of temperature. We have used these measurements to estimate, close to the melting point, the solubility of oxygen (X/sub 0//sup b/, < 10/sup -4/) and its surface segregation coefficient ..beta../sup s/(> 10/sup 3/). 8 refs., 5 figs., 1 tab.

The results of EP-toxicity tests on mercury saturated Duolite{reg_sign} GT-73 cation exchange resin clarify options for the ultimate disposal of spent resin. Samples of GT-73 saturated with mercury passed the EP-toxicity test, indicating that fully spent resin may be classifed as ``solid``-not``hazardous``-waste and stored or disposed-of as such. Samples of GT-73 resin saturated with mercury and then incorporated into Portland Type 1 cement did not pass the EP-toxicity test and fall into the ``hazardous waste`` category. Samples of GT-73 resin less-than-saturated with mercury which were in corporated in Portland Type 1 cement passed the EP-toxicity test and may be classified as ``solid waste.`` Other commercially available materials are being investigated for incorporating fully spent GT-73 resin in a solid waste form.