This article discusses the thermal annealing behavior of an oxide layer under silicon.

Article discussing a study of the rapid isothermal anneal of 75As implanted silicon.

Article discussing M-shell x-ray-production cross sections in thin targets of ₇₉Au, ₈₂Pb, ₈₃Bi, and ₉₂U by 0.3 - 2.6-MeV ₁⁴H+ and ₂⁴He+ ions.

Article on thermochemical investigations of gas-liquid chromatography and partition coefficients of inert solutes on self-associating binary solvent mixtures.

Article on the utilization of hospital services by older adults and a look at today's trends and projections for tomorrow.

Article on older adults' use of health maintenance organizations.

Article on the solubility in binary solvent systems I and the specific versus nonspecific interactions.

The objective of the waste package program is to insure that a package is designed suitable for a repository in tuff that meets performance requirements of the NRC. In brief, the current (draft) regulation requires that the radionuclides be contained in the engineered system for 1000 years, and that, thereafter, no more than one part in 10{sup 5} of the nuclides per year leave the boundary of the system. Studies completed as of this writing are thermal modeling of waste packages in a tuff repository and analysis of sodium bentonite as a potential backfill material. Both studies will be presented. Thermal calculations coupled with analysis of the geochemical literature on bentonite indicate that extensive chemical and physical alteration of bentonite would result at the high power densities proposed (ca. 2 kW/package and an area density of 25 W/m{sup 2}), in part due to compacted bentonite`s relatively low thermal conductivity when dehydrated ({similar_to}0.6 +- 0.2 W/m{sup 0}C). Because our groundwater contains K{sup +}, an upper hydrothermal temperature limit appears to be 120 to 150{sup 0}C. At much lower power densities (less than 1 kW per package and an areal density of 12 W/m{sup 2}), bentonite may be suitable.

The Nevada Nuclear Waste Storage Investigations, which is evaluating potential locations for a high-level waste repository at the Nevada Test Site and environs, is currently focusing its investigations on tuff, principally in Yucca Mountain, as a host rock. This paper discusses some of the geochemical investigations. Particular emphasis is placed on definition of some basic elements and necessary technical approaches for the geochemistry data acquisition and modeling program. Some site-specific tuff geochemical information that is important for site selection and repository performance will be identified and the current status of knowledge will then be discussed.

The vadose zone in arid regions is considered as a possible environment for geologic isolation of nuclear waste. There are several topographic and lithologic combinations in the vadose zone of arid regions that may lend themselves to waste isolation considerations. In some cases, topographic highs such as mesas and interbasin ranges - comprised of several rock types, may contain essentially dry or partially saturated conditions favorable for isolation. The adjacent basins, especially in the far western and southwestern US, may have no surface or subsurface hydrologic connections with systems ultimately leading to the ocean. Some rock types may have the favorable characteristics of very low permeability and contain appropriate minerals for the strong chemical retardation of radionuclides. Environments exhibiting these hydrologic and geochemical attributes are the areas underlain by tuffaceous rocks, relatively common in the Basin and Range geomorphic province. Adjacent valley areas, where tuffaceous debris makes up a significant component of valley fill alluvium, may also contain thick zones of unsaturated material, and as such also lend themselves to strong consideration as respository environments. This paper summarizes the aspects of nuclear waste isolation in unsaturated regimes in alluvial-filled valleys and tuffaceous rocks of the Basin and Range province.

At Yucca Mountain, a potential site for a high-level nuclear waste repository on the Nevada Test Site in southern Nevada, evaluation of the geologic setting and rock physical properties, along with previous regional hydrologic studies, has provided background that can be used for construction of a preliminary conceptual hydrologic model of the unsaturated zone. The 500-m-thick unsaturated portion of Yucca Mountain consists of alternating layers of two contrasting types of tuff. One type consists of highly fractured, densely welded, relatively nonporous but highly transmissive ash-flow tuffs. The other type consists of relatively unfractured, nonwelded, highly porous but relatively nontransmissive, argillic and zeolitic bedded tuffs and ash-flow tuffs. The contrast between these two sets of distinctive physical properties results in a stratified sequence best described as "physical-property stratigraphy" as opposed to traditional petrologic stratigraphy of volcanic rocks. The vast majority of recharge through the unsaturated zone is assumed to be vertical; the dominant migration may occur in fractures of densely welded tuffs and in the matrix of nonwelded tuff, but the mode of fluid flow in these unsaturated systems is undetermined. Limited lateral flow of recharge may occur at horizons where local perched water tables may exist above relatively nontransmissive zeolitized …

Leach testing experiments were conducted on SYNROC-D material to examine the parameters which affect leaching results and to measure the activation energy for leaching of elements from SYNROC-D. Measured leach rates were found to be controlled by precipitation of insoluble phases for those tests where the sample surface area to volume of leachant (SA/V) multiplied by leaching time (t) exceeded 0.3 cm{sup -1}d for leach tests at 90{sup 0}C. In these cases the apparent activation energy for leaching was approximately 10 kcal/mole based on Na and Si data. For leach tests at 90{sup 0}C with (SA/V)(t) less than 0.2 cm{sup -1}d, the activation energy for Na and Si dissolution was 18.5 kcal/mole for sample S29 and 14.5 kcal/mole for sample LS04. These activation energies are in agreement with values reported by Tole and Lasaga (1981) for nepheline dissolution. The effect of sample geometry was investigated by leaching a series of crushed samples of different grain size. The results support the view that geometric surface area should be used in leach rate calculations rather than gas adsorption BET surface area. Comparison of results on S29 leaching of crushed samples and monoliths show that data from MCC-1 and ISO type leach tests …

The Spent Fuel Test-Climax (SFT-C) is located at a depth of 420 m in the Climax granite at the Nevada Test Site. The test array contains 11 canistered PWR fuel assemblies, plus associated electrical simulators and electrical heaters. There are nearly 900 channels of thermal, radiation, stress, displacement, and test control instrumentation. This paper is a general status report on the test, which started in May 1980.

This paper has brought out the unique properties of tuffs and related them to needs associated with their use as a host rock for a high level nuclear waste repository. Major issues of temperature, pore water, joints, and depositional patterns have been identified and related responses and impacts outlined in Table 1. Planned experiments have been outlined and their relationships to the rock mechanics issues summarized in Table 2. The conclusions from this paper are: (1) tuff is a complex rock and basic phenomenological understanding is incomplete; and (2) available field test facilities will be used for a series of experiments designed to improve phenomenological understanding and support repository design efforts.

A carbon steel storage canister has been designed for the dry encapsulation of spent nuclear fuel assemblies or of logs of vitrified high level radioactive waste. The canister design is in conformance with the requirements of the ASME Code, Section III, Division 1 for a Class 3 vessel. The canisters will be loaded and sealed as part of a completely remote process sequence to be performed in the hot bay of an experimental encapsulation facility at the Nevada Test Site. The final closure to be made is a full penetration butt weld between the canister body, a 12.75-in O.D. x 0.25-in wall pipe, and a mating semiellipsoidal closure lid. Due to a combination of design, application and facility constraints, the closure weld must be made in the 2G position (canister vertical). The plasma arc welding system is described, and the final welding procedure is described and discussed in detail. Several aspects and results of the procedure development activity, which are of both specific and general interest, are highlighted; these include: The critical welding torch features which must be exactly controlled to permit reproducible energy input to, and gas stream interaction with, the weld puddle. A comparison of results using automatic …

The Nevada Nuclear Waste Storage Investigations (NNWSI) are part of the National Waste Terminal Storage (NWTS) program being conducted by the Department of Energy. Within the NWTS program, the NNWSI is the component that focuses on siting evaluations on and near the Nevada Test Site (NTS). The objectives of the Nevada project include evaluating the suitability of a Test and Evaluation Facility (TEF) site on or near the NTS, evaluating the suitability of a commercial nuclear waste repository site on or near the NTS, and supporting the NWTS program with research that is uniquely possible at NTS. Current engineering studies suggest that TEF and repository surface facilities would need to be located on gently sloping alluvium east of Yucca Mountain. Access from surface facilities to underground waste emplacement areas would be by vertical shafts and horizontal drifts, or possibly by inclined adits. The current NNWSI schedule includes an exploratory shaft location and horizon recommendation in 12/82, with a start of exploratory shaft drilling in 9/83. Because of the complexities of horizon selection, it is possible that the exploratory shaft depth or horizon recommendation may involve the exploration of more than one horizon. Phase I of the exploratory shaft, determination of …

The Spent Fuel Test-Climax (SFT-C) is being conducted under the technical direction of the Lawrence Livermore National Laboratory for the US Department of Energy. The SFT-C is located 420 m below surface in the Climax placed in test storage in April and May 1980. At the same time, 6 electrical elevated-temperature phase of the test. Data related to heat transfer, thermomechanical response, radiation dose, and radiation damage have been collected and are presented here, as appropriate, with calculational results. In general, measured and calculated results compare well.

Horizontal and vertical measurements of drift closures have been made with a manually operated tape extensometer since about 6 weeks after the emplacement of the spent fuel at various locations along the length of the drifts. The averaged closures are less than 0.6 mm from the onset of measurements through about two years after the spent fuel emplacement. These results have been compared with thermo-elastic finite element calculations using measured medium properties. The comparisons show that most of the closure of the drifts occurred between the time the spent fuel was emplaced and the time of first measurement. The comparisons show that the results track each other, in that where closure followed by dilation is measured, the calculations also show this effect. The agreement is excellent, although where closures of less than 0.2 mm are measured the comparison with calculations is limited by measurement reproducability. Once measurements commenced the averaged measured closures remain to within 30% of the calculated total closure in each drift. 9 figures, 1 table.

Much of the tritium found in soil and leaf litter near a chemical separations facility is incorporated into soil organic matter in a stable non-exchangeable form. Formation of this ''bound'' tritium seems to result from the uptake of molecular tritium (HT) by living pine needles. Soil and litter microbes convert HT to HTO more rapidly, but no measurable organic tritium is formed. This report discusses this study.

An instrument has been developed and tested for nondestructive assay of 235U enrichment of uranium oxide powder contained in sealed 1-gallon cans. A theoretical correlation of enrichment vs. count rate agrees well with the calibration measurements and provides guidelines for applicability. A microcomputer simplifies operator requirements and provides on-line enrichment results.

Article on the biosynthesis of isoflavonoid phytoalexins and the incorporation of sodium [1,2-(13)C2] acetate into phaseollin and kievitone.

Abstract: Near-death studies published in major scientific journals during 1981-82 are grouped by subject matter and briefly reviewed.

Partial Abstract: "This paper examines tunnel experiences, which have been discussed by Raymond Moody, Kenneth Ring, and Kevin Drab in the context of near-death experiences. It is argued that tunnel experiences, even when possibly triggered by psi cognition, are not always associated with near-death experiences or out-of-body experiences. A proposed definition of pseudo-hallucinations is adapted to possible psi-induced tunnel experiences." Six categories of tunnel experiences are outlined, a "transactional view of visual perception is accepted", and the hypothesis that the tunnel is a "subconsciously devised artifact for overcoming a spatial and/or temporal gap at the perceptual level" is proved true. This view is then compared with approaches from different writers on this topic. Additionally, a new solution for why tunnels are missing in cases of "clairvoyant travel" is given.

Abstract: This study reports the results of a multivariate analysis of data from 33 subjects who had near-death experiences. The analysis examined the relationship between the phenomenology of the experience and preexisting conditions. Five clusters were derived: Low Stress, Emotional Stress, Intoxicant, Cardiac Arrest, and Anesthetic. The heuristic value of these clusters is discussed. The statistical technique used is also discussed in some detail since it is particularly suitable for category data of this type where small numbers of subjects and large numbers of variables are involved in the analysis.