In situ thermal tests, which are to be conducted in the Exploratory Studies Facility (ESF) at Yucca Mountain, will provide a major portion of the experimental basis supporting the validation of coupled thermal-hydrological-geomechanical-geochemicaI (T-H-M-C) process models required to assess the total system performance at the site. With respect to advective rock dryout, we have identified three major T-H flow regimes: (1) throttled, nonbuoyant, advective rock dryout; (2) unthrottled, nonbuoyant, advective rock dryout; and (3) unthrottled, buoyant, advective rock dryout. With the V-TOUGH code, we modeled a range of heater test sizes, heating rates, and heating durations under a range of plausible hydrological conditions to help optimize an in situ thermal test design that provides sufficient information for determining (a) the dominant mode(s) of heat flow, (b) the major T-H regime(s) and processes (such as vapor diffusion) that govern the magnitude and direction of vapor and condensate flow, and (c) the influence of heterogeneous properties and conditions on the flow of heat, vapor, and condensate. For the plate thermal test, which uniformly heats a disk-shaped area, we evaluated a wide range of test areas, ranging from 50 to 5077 m{sup 2}. We evaluated the single-drift thermal test, which consists of a …

This document presents information about a fire that occurred in January 1996 at Lawrence Livermore National Laboratory. This fire was caused by the spontaneous combustion of 100% fuming nitric acid. Topics discussed include: Summary of the incident; technical background; procedural background; supervision; previous incidents with 100% fuming nitric acid; and judgment of potential hazards.

In this paper we discuss aspects of a comprehensive program to identify and bound potential effects of microorganisms on long-term nuclear waste containment, using as examples, studies conducted within the Yucca Mountain Project. A comprehensive program has been formulated which cuts across standard disciplinary lines to address the specific concerns of microbial activity in a radioactive waste repository. Collectively, this program provides bounding parameters of microbial activities that modify the ambient geochemistry and hydrology, modify corrosion rates, and transport and transform radionuclides under conditions expected to be encountered after geological waste emplacement. This program is intended to provide microbial reaction rates and bounding conditions in a form that can be integrated into existing chemical and hydrological models. The inclusion of microbial effects will allow those models to more accurately assess long term repository integrity.

The impacts of the native and introduced bacteria on the performance of geologic nuclear waste disposal facilities should be evaluated because these bacteria could promote corrosion of repository components and alteration of chemical and hydrological properties of the surrounding engineered and rock barriers. As a first step towards investigating these potentialities, native and introduced bacteria obtained from post-construction Yucca Mountain (YM) rock were isolated under varying conditions, including elevated temperature, low nutrient availability, and the absence of available oxygen. Individual isolates are being screened for activities associated with microbially induced corrosion of metals (MIC). Preliminary determination of growth rates of whole YM microbial communities under varying conditions was also undertaken.

Large quantities of Defense related spent nuclear fuels are being stored in water basins around the United States. Under the non-proliferation policy, there has been no processing since the late 1980`s and these fuels are caught in the pipeline awaiting stabilization or other disposition. At the Savannah River Site, over 200 metric tons of aluminum clad fuel are being stored in four water filled basins. Some of this fuel has experienced visible pitting corrosion. An intensive effort is underway at SRS to understand the corrosion problems and to improve the basin storage conditions for extended storage requirements. Significant improvements have been accomplished during 1993-1996. This paper presents a discussion of the fundamentals of aluminum alloy corrosion as it pertains to the wet storage of spent nuclear fuel. It examines the effects of variables on corrosion in the storage environment and presents the results of corrosion surveillance testing activities at SRS, as well as discussions of fuel storage basins at other production sites of the Department of Energy.

Electron beam dry scrubbing is a technique for removing in a single step both nitrogen oxides (NO{sub x}) and sulfur dioxide (SO{sub 2}) from the off-gas generated by utilities burning high sulfur coal. The use of pulsed electron beams may provide the most cost-effective solution to the implementation of this technique. This paper presents the results of plasma chemistry calculations to study the effect of dose rate, pulse length and pulse repetition rate on pulsed electron beam processing of NO{sub x} and SO{sub 2} in flue gases. The main objective is to determine if the proposed combinations of dose rate, pulse length and pulse repetition rate would have any deleterious effect on the utilization of radicals for pollutant removal. For a dose rate of 2x10{sup 5} megarads per second and a pulse length of 30 nanoseconds, the average dose per pulse is sufficiently low to prevent any deleterious effect on process efficiency because of radical-radical recombination reactions. During each post-pulse period, the radicals are utilized in the oxidation of NO{sub x} and SO{sub 2} in a timescale of around 200 microseconds; thus, with pulse frequencies of around 5 kilohertz or less, the radical concentrations remain sufficiently low to prevent any …

Among the new methods being investigated for the post-process reduction of volatile organic compounds (VOCs) in atmospheric-pressure air streams are based on non-thermal plasmas. Electron beam, pulsed corona and dielectric-barrier discharge methods are among the more extensively investigated techniques for producing non-thermal plasmas. In order to apply non-thermal plasmas in an industrial scale, it is important to establish the electrical power requirements and byproducts of the process. In this paper the authors present experimental results using a compact electron beam reactor, a pulsed corona and a dielectric-barrier discharge reactor. They have used these reactors to study the removal of a wide variety of VOCs. The effects of background gas composition and gas temperature on the decomposition chemistry have been studied. They present a description of the reactions that control the efficiency of the plasma process. They have found that pulsed corona and other types of electrical discharge reactors are most suitable only for processes requiring O radicals. For VOCs requiring copious amounts of electrons, ions, N atoms or OH radicals, the use of electron beam reactors is generally the best way of minimizing the electrical power consumption. Electron beam processing is remarkably more effective for all of the VOCs tested. …