Glass dissolution rates decrease dramatically as glasses approach "saturation" with respect to the leachate solution. This effect may lower the dissolution rate to 1/100 to 1/1000 of the unsaturated rate. Although rate controls on glass dissolution are best understood for conditions far from saturation, most repository sites are chosen where water fluxes are minimal, and therefore the waste glass is most likely to dissolve under conditions close to saturation. Our understanding of controls on dissolution rates close to saturation, versus far from saturation, are therefore of greater significance for assessing release rates of radionuclides from repositories. The key term in the rate expression used to predict glass dissolution rates close to saturation is the affinity term, which accounts for saturation effects on dissolution rates. The form of the affinity term and parameters used to model glass dissolution are clearly critical for accurate estimates of glass performance in a repository. The concept of saturation with respect to glass dissolution is problematic because of the thermodynamically unstable nature of glass. Saturation implies similar rates of forward (dissolution) and back (precipitation) reactions, but glasses cannot precipitate from aqueous solutions; there can be no back reaction to form glass. However experiments have shown that …

The US is currently evaluating the use of MOX fuel in commercial LWR's for reducing weapons grade Pu stockpiles. The design and licensing processes will require that the validity of the nuclear data libraries and codes used in the effort be demonstrated. Unfortunately, there are only a very limited number of relatively old and non representative integral experiments' freely available to the US programs. This lack of adequate experimental data can be partially remediated by comparing the results of well validated European codes with the results of candidate US codes. The demonstration can actually be divided in two components: a code to code (Monte Carlo) comparison can easily demonstrate the validity and limits of the proposed algorithms; and the performances of nuclear data libraries should be compared, major trends should be observed, and their origins should be explained in terms of differences in evaluated nuclear data; In this paper, we have compared the performances of the JEF-2.2 and ENDF/B-VI.4 libraries for a series of benchmarks for k{sub eff}, void worth, and pin power distributions. Note that JEF-2.2 has been extensively validated for MOX applications.

The primary objective of the project is to construct a subsurface transect of Cretaceous strata that were deposited in the Kansas-Colorado-Utah corridor, going from marine sequences that contain organic-carbon-rich hydrocarbon source rocks in Kansas and eastern Colorado to nearshore coal-bearing units in western Colorado and Utah. The drilling transect will provide continuous, unweathered samples for inorganic, organic, and isotopic geochemical studies and mineralogical investigations to determine the characteristics of hydrocarbon source rocks. This transect also will provide information on the extent of thermal maturation and migration of hydrocarbons in organic-carbon-rich strata along a burial gradient. In addition, the eastern Colorado hole will provide characteristics of an important fractured reservoir (the Pierre Shale) in the Florence oil field, the oldest continuously producing field in the United States (>100 years; 600 wells; >14 Mbbls).

This report should be useful for tracking appropriations and authorization actions on the DOE R&D programs, and the potential implications of those actions.

This report focuses on the R&D programs. It divides the programs into four categories: energy resources R&D, science, national security R&D, and environmental quality R&D. Those categories, which approximate the way DOE has divided up its programs, are set up to keep similar research activities together.(1) R&D funding is concentrated in the first three. The report gives a description of the programs within each category including their research objectives and the activities where significant budget changes were requested for FY1999. It then describes the request, and congressional appropriation and authorization action. There follows a discussion of issues about the FY1999 request that are emerging during congressional consideration of the budget.

In the second quarter of calendar year 1998, no work was performed on the present project. The 20 MMBtu/hr combustor-boiler facility was not operated during this period. The total test days on the Philadelphia facility to the end of June 1998 remained at 108 as in the previous quarter. Of these, 34 tests were part of the other DOE project. The test days on the other project are listed here because they demonstrate the durability of the combustor, which is one of the objectives of the present project. As noted previously, this exceeds the planned 63 test days for this project. All key project objectives have been exceeded including combustor durability, automated combustor operation, NO{sub x} emissions as low as 0.07 lb/MMBtu and SO{sub 2} emissions as low as 0.2 lb/MMBtu. In addition, a novel post-combustion NO{sub x} control process has been tested on a 37 MW and 100 MW utility boiler. Any further tests will depend on the results of evaluations of current and prior tests. The only effort remaining on this project is facility disassembly and Final Report. Also, as part of the commercialization effort for this combustor technology, Coal Tech is developing alternative designs of the combustor …

Existing methods for qualifying digital system software for use in safety critical systems are expensive and are based on inferences that are of doubtful validity. This report on work-in-progress describes a new approach to qualifying a class of small safety systems that can meet a number of design restrictions, where the restrictions are carefully crafted to permit safety qualification to be determined by means of static analysis of the software combined with a limited amount of testing. This approach differs from attempts to qualify unrestricted programs in the general case. Work that has been accomplished towards this goal is discussed in summary terms. The technique relies on transforming a program into a form of directed graph known as a flowgraph. Existing testing theory is used, sometimes with minor modifications, to derive a set of design restrictions that permit reasoning about safety properties of the program, based on analysis and limited testing. Future work required to complete the research is outlined.

The goal of this research is to engineer enzymes to be efficient and economically attractive catalysts for the chemical industry. The author is attempting to demonstrate generally-applicable approaches to enzyme improvement as well as develop specific catalysts for potential industrial application. Progress on three tasks are described: Random mutagenesis of pNB esterase--improved activity and stability; Directed evolution of subtilisin E to enhance thermostability; and Methods for invitro recombination.

This report provides an overview of federal pay Salary adjustments for Fiscal Year 1999

This report analyzes the pay adjustment that Federal employees are to receive in fiscal 1999 under P.L. 101-509, the Federal Employees Pay Comparability Act.

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The NIF target chamber beam dumps must survive high x-ray, laser, ion, and shrapnel exposures without excessive generation of vapors or particulate that will contaminate the final optics debris shields, thereby making the debris shields susceptible to subsequent laser damage. The beam dumps also must be compatible with attaining and maintaining the required target chamber vacuum and must not activate significantly under high neutron fluxes. Finally, they must be developed, fabricated, and maintained for a reasonable cost. The primary challenge for the beam dump is to survive up to 20 J/cm{sup 2} of lpm light and 1 - 2 J/cm{sup 2} of nominally 200 - 350 eV blackbody temperature x rays. Additional threats include target shrapnel, and other contamination issues. Designs which have been evaluated include louvered hot-pressed boron carbide (B{sub 4}C) or stainless steel (SS) panels, in some cases covered with transparent Teflon film, and various combinations of inexpensive low thermal expansion glasses backed by inexpensive absorbing glass. Louvered designs can recondense a significant amount of ablated material that would otherwise escape into the target chamber. Transparent Teflon was evaluated as an alternative way to capture ablated material. The thin Teflon sheet would need to be replaced after each …

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Boron-nitride (BN) films are deposited by the reactive sputter deposition of fully dense, boron targets utilizing a planar magnetron source and an argon-nitrogen working gas mixture. Near-edge x-ray absorption fine structure analysis reveals distinguishing features of chemical bonding within the boron is photoabsorption cross-section. The hardness of the BN film surface is measured using nanoindentation. The sputter deposition conditions as well as the post-deposition treatments of annealing and nitrogen-ion implantation effect the chemical bonding and the film hardness. A model is proposed to quantify the film hardness using the relative peak intensities of the p*-resonances to the boron 1s spectra.

A beam chopper together with the temporal structure of x-rays emitted by a synchrotrons storage ring can be utilized to generate x-ray bursts of variable length and time separation. A Si cube, cut for diffraction from the (220) planes, was mounted to a low-speed motor to produce a beam chopper based upon the Darwin width of the crystal. An x-ray pulse, consisting of an envelope of individual pulses characterizing the loading pattern of the storage ring, was transmitted. The width of the transmitted pulse and the time between pulses was varied by varying the rotation frequency of the Si cube. Pulses as short as {approx} 75 ps or as long as {approx} 4 {micro}s were transmitted with pulse separation spanning from 4 ms to 167 ms.

We have used piezo-driven Fabry-Perot interferometers in the past far many continuous velocity-time measurements of fast moving surfaces. In order to avoid the annoying drift of some of these devices, we have developed and used inexpensive, solid glass, striped etalons with lengths up to 64 mm. Usable apertures are 35 mm by 80 mm with a finess of 25. A roundabout technique was devised for double cavity operation. We built a passive thermal housing for temperature stability, with tilt and height adjustments. We have also developed and used our first fixed etalon air-spaced cavity with a rotatable glass double- cavity insert. The rotation allows the referee cavity fractional order to be adjusted separately from that of the main cavity. It needs very little thermal protection, and eliminates the need for a roundabout scheme for double cavity operation, but is more costly than the solid glass version I

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As a part of the SRS Beneficial Reuse Program, stainless steel radioactive scrap metal is melted, pour into ingots, and roll into sheets. The sheets are then fabricated into boxes and barrels for beneficial reuse. The melting activity is a partial decontamination process. Certain isotopes separate from the melted steel, while others stay in solution. Cobalt-60 is the primary constituent, which remains in solution, and becomes the major contributor to the volumetric radioactivity of the finished products (boxes and barrels). There is currently no ``de minimis`` free release level for volumetrically radioactive material. However, under certain circumstances, pathway analysis can be used (and have been used) to free release volumetrically radioactive material. This paper presents an analysis using empirical data derived from over sixty ``melts``, to demonstrate that the implied surface radioactivity for specific beneficial reuse products is within free release limit. The approach can be applied to other recycled metal products.