The design-basis, defense-related, transuranic (TRU) waste to be emplaced in the Waste Isolation Pilot Plant (WIPP) could, if sufficient H{sub 2}O and nutrients were present, produce as much as 1,500 moles of gas per drum of waste. Gas production could pressurize the repository to 150 atm (lithostatic pressure) and perhaps higher. Anoxic corrosion of Fe and Fe-base alloys and microbial degradation of cellulosics are the processes of greatest concern, but radiolysis of brine could also be important. The proposed backfill additives CaCO{sub 3}, CaO, CuSO{sub 4}, KOH, and NaOH may remove or prevent the production of some of the expected gases. Because of the heterogeneous nature of design-basis waste, the Eh and pH of any brine present in WIPP disposal rooms could vary significantly over short distances after reacting with the waste. The WIPP Project is investigating the consequences of gas production and considering engineered alternatives, including reprocessing the waste, to reduce gas production rates or potentials. Reprocessing would also reduce the range of Eh and pH expected for the repository. 12 refs.
More than 20 years ago, a philosophy was developed for the design and analysis of hardware systems to ensure that they would perform in a predictably safe manner, even in severe abnormal environments. This philosophy has been scrutinized and tested during the intervening years, and has proved successful in practice. A requirement guiding the development of the philosophy was that the resulting design must be simple enough to be amenable to analysis. The inherent simplicity is a safety attribute, because complex analyses, such as those represented by fault trees containing hundreds of branches, are extremely susceptible to error. There are many examples where such errors led analysts to believe systems were safe when they were not, with disastrous consequences. The purpose of this workshop problem is to determine whether the principles developed to ensure hardware safety are applicable in any way to safety-critical software systems. It is possible that hardware associations with software will need to be considered, but whether or not this is true is left as an aspect of the investigation. In order to put the ground rules in perspective, it will be necessary to establish some framework.
We present here the SMILE modification of the RADLAC II accelerator which enabled us to produce high quality 12--14 MV, 100 kA beams. It consists of replacing the 40-kA 4-MV beam injector, magnetic vacuum transport and accelerating gaps by a long cathode shank which adds up the voltages of the 8 pulse forming lines. The beam now is produced at the end of the accelerator and is free of all the possible instabilities associated with accelerating gaps and magnetic vacuum transport. Annular beams with {beta}{perpendicular} {le} 0.1 and radius r{sub b} {le} 2 cm are routinely obtained and extracted from a small magnetically immersed foilless electron diode. Results of the experimental evaluation are presented and compared with design parameters and numerical simulation predictions. 6 refs., 7 figs., 1 tab.
A diode employing a thermionic cathode has produced 80 A beams at 200 kV for at least 6 {mu}s. Moreover, the diode operates at rates as high as 1 Hz. EGUN simulations of the experimental geometry agree with the experiments. Finally, simulation of a proposed diode geometry predicts a 1 kA, 500 kV beam.
An algorithm is presented or rendering scalar field data which reduces rendering times by as much as two orders of magnitude over traditional full resolution image. Less than full resolution sampling of the scalar field is performed using a fast ray tracing method. The sampling grid points are output as a set of screen based gouraud shaded polygons which are rendered in hardware by a graphics workstation. A gradient based variable resolution algorithm is presented which further improves rendering speed. Several examples are presented. 16 refs., 8 figs., 2 tabs.
Efficient conversion of radioactive decay to electrical power has been the goal of a number of past research efforts. One of these was the Elgin-Kidde nuclear battery. In this concept promethium-147 was used as a beta source which was then mixed with a phosphor to produce a radioluminescent (RL) source of light. The light source was coupled to silicon photovoltaic converters to create electricity. This photoelectric approach is being revisited using tritium based solid state compounds and advanced gas concepts to produce RL light sources being disclosed at this conference. Efficient conversion of the RL light energy to electrical energy imposes certain requirements on the semiconductor converter. These requirements will be discussed. Projections of power source electrical and physical characteristics will be presented based on reasonable design parameter assumptions. The words Power Supply'' usually evoke a vision of a rotating machine or chemical battery. However, today's technology is making increasing use of photonics, where information and even power can be moved through optical fibers. Brighter volumetric RL light sources open a whole new range of photonics-based applications, while solid state tritiated compounds provide the foundation for improved mechanical adaptability and safety. 4 refs., 6 figs., 1 tab.
We describe the development of the first all-organic, opitcally clear, radioluminescent (RL) light. Although gas-phase RL lights have been known for many years, a number of advantages accrue to solid state devices. These include greater ruggedness and ease of brightness scale-up. In our systems, tritium is covalently bound to an organic getter, which is dissolved in an organic monomer, along with appropriate scintillating dyes. The entire system cures by monomer polymerization due to the radiation field, resulting in a clear, glowing solid plastic block. We outline here the design considerations employed in producing these materials. 12 refs., 1 fig.
The initial reactions that occur during liquefaction can have significant impacts on process yields and downstream process conditions. Reactions that result in compounds with low molecular weights and decreased boiling points are beneficial, whereas retrogressive reactions, which yield higher molecular weight compounds that are refractory to further processing, give lower yields of desired products. The objectives of this research are to determine the process conditions that give rise to retrogressive reactions during preconversion processing and to identify methods for minimizing the occurrence of these reactions. Initial studies have been performed using dibenzyl ether as a compound to model ether linkages in coal. Results show that retrogressive reactions can occur at temperatures as low as 180{degree}C. The presence of a good hydrogenation catalyst and a hydrogen donor was found to minimize retrogressive reactions, whereas the presence of mineral matter, primarily clay minerals, and ZnCl{sub 2}, enhanced the reactions. 8 refs., 3 figs.
Under the sponsorship of the United States Nuclear Regulatory Commission (NRC), Sandia National Laboratories is conducting several research programs with the common goal of developing a complete methodology for the prediction of the ultimate pressure capacity, at elevated temperatures, of light water reactor (LWR) containment systems. These programs are collectively known as the Containment Integrity Programs. This paper will provide a brief overview of these programs. As a part of the Containment Integrity Programs, a series of scale model containment test have been conducted at Sandia including a 1:8-scale steel model and a 1:6 scale reinforced concrete model. The model were pneumatically pressurized up to point of functional failure; that is, the point at which the containment was no longer effective in preventing significant leakage past its pressure boundary. Also, a 1:10-scale prestressed concrete model has been hydrostatically tested in the United Kingdom under a cooperative agreement with the NRC and others. Because the containment pressure boundary consists of numerous mechanical and electrical penetrations, several independent test programs of typical penetrations have also been performed to determine their leakage behavior when subjected to severe accident conditions. Completed containment penetration research programs include testing of typical compression seals and gaskets, inflatable seals, a personal air lock and electrical penetration assemblies (EPAs). Also, an investigation of leakage due to ovalization of penetration sleeves has been conducted as a part of the scale model test. Currently, testing of the unseating equipment hatch of the 1:6-scale containment model is under way. 23 refs., 3 figs., 2 tabs.
The CONTAIN code is a system-level analysis tool developed for the USNRC, and is intended for best-estimate prediction of conditions which might occur in the containment building of a nuclear power plant during a severe accident. A key feature of the code is that it models the containment phenomena in an integrated manner. In particular, the CONTAIN code models some of the complex ways that thermal hydraulics and aerosol phenomena interact with each other. The Light Water Reactor Aerosol Containment Experiment (LACE) progarm is a program to aid researchers in their understanding of thermal hydraulic and aerosol behavior within containments. The purpose of this paper is to report on best-estimate LA-4 post-test calculations that have been completed with the most recent version of the CONTAIN code, version 1.11. An analysis of experimental data and review of the blind post-test CONTAIN calculations is used to justify a re-calculation of the experiment and to establish a best-estimate calculation. The best-estimate calculation shows that reasonably good agreement between thermal hydraulic predictions and data can be obtained with the current CONTAIN models by varying experimental parameters within their uncertainties. Furthermore, with the recently added solubility model for hygroscopic aerosols, the best-estimate calculation gives aerosol behavior that is in good agreement with aerosol data. 10 refs., 16 figs.
Sandia National Laboratories is in the process of upgrading the Central Computing Network, which is a large heterogeneous network providing scientific computing, file storage, output services, and remote access to network resources. The migration from the present HYPERchannel-50 technology to HYPERchannel-100 is currently in progress and plans to migrate to the Fiber Distributed Data Interface (FDDI) token ring architecture are being considered. A migration from a variety of proprietary protocols to a primarily TCP/IP environment is also in progress. In order to test the feasibility of the Network Systems Corporation FDDI technology platform, two test rings have been constructed. Ring A' consists of nine dual attached Data Exchange Units (DXUs) and ring B' consists of two dual attached DXUs. The rings are linked together using N715 DXUs. Other DXU models (with associated host computers where applicable) include N130s, an N220, N400s, and FE640 IP routers. Test data on fault isolation and recovery mechanisms, performance, IP routing (within and between rings), and monitor capabilities will be presented. Interoperability' data based on tests between DXUs and Sun FDDI workstations will also be presented. 14 figs.
Experiments at Sandia National Laboratories have studied the operation of the linear-induction accelerators, HELIA and Hermes 3, in positive polarity. These experiments have provided a unique opportunity to explore the consequences of multiple-cathode electron emission in magnetically insulated transmission lines. An examination of the total energy-canonical momentum distribution of the electrons explains the features of the magnetically insulated flow exhibited by these systems. Simple analysis based on the basic concept of pressure balance, in conjunction with particle-in-cell numerical simulations, shows how the line voltage is related to the anode and cathode currents. Two flow designations are introduced that can apply to multiple-cathode magnetically insulated transmission lines: full-gap flow (FGF), and locally emitted flow (LEF). 16 refs., 15 figs.
An extensive optical fiber (o.f.) cable plant has been constructed in the Central Computing Facility (CCF) of Sandia National Labs to support the NSC DX platform with the Fiber Distributed Data Interface (FDDI) network. The cable plant was designed to optimize flexibility, maintainability, expandability, performance, and capacity. More than 2km of fiber cable and over 3400 connectors were installed. Each component of the cable system was carefully evaluated in order to meet the design requirements and conform to standards. A detailed statement of work (SOW) was generated to assure proper implementation of the design by a qualified contractor. Following the installation of the o.f. cable plant, a heterogenous, production network was built to utilize the benefits of the new media and interfaces.
The optimized C{sub 2v} geometry of ortho-carborane, 1,2-C{sub 2}B{sub 10}H{sub 12}, is determined from Hartree-Fock calculations. For this geometry, a carbon atom is substituted for a boron atom at one of the 4 inequivalent boron sites and the ground-state unrestricted Hartree-Fock eigenvalues and molecular orbitals are found. One thus obtains the valence structure of the B(1s) core-excited molecule according to the Z + 1 approximation. The eigenvalue of the highest occupied molecular orbital is then subtracted from the experimental B(1s) ionization energy of the same site in ortho-carborane. This determines the excitation energy of the most tightly bound exciton for that site. Three of the sites yield nearly identical excitation energies of 191.9 eV; the fourth site yields an excitation energy of 190.9 eV. 8 refs., 1 fig., 2 tabs.
A large area surface source of Lithium plasma for use as an ion source in the PBFA-2 ion beam diode is described. BOLVAPS produces a 1--2 mm thick layer of Li vapor with a density approaching 1 {times} 10{sup 17} cm{sup {minus}3} by rapid ohmic heating of a thin film laminate, one layer of which contains Li. The principal design issues of the vapor source being built for use on the PBFA-2 accelerator are described. LIBORS uses 670.8 nm laser light to efficiently ionize the Li vapor. The results of small-scale Physics tests and full-scale component development are summarized. 13 refs., 6 figs.
An applied B-field ion diode has been operated at 21 TW on PBFA 2 to study beam generation and transport physics. The radial focusing 15-cm-radius diode utilized a pair of magnet coils in disc cathode structures to produce an axial B-field to minimize electron loss in the 16 mm anode-cathode gaps. The diode was different than used in the past with the cathodes 20% closer together and the B-field increased to 3.3 T at the midplane. The 2.5 MA beam originated from a 5-cm-tall ion emitting region and was transported toward the axis in a 12.5-cm-radius gas cell with 2-{mu}m-thick mylar window and a 5-Torr-argon gas fill. A surface flash-over plasma created by electron loss on wax-filled grooves in the anode produced a beam with comparable currents of proton and carbon ions. The experimental results include the spatial uniformity and time dependence of proton and carbon beam emission from the anode and the divergence and focusability of both beams. 10 refs., 13 figs.
Anomalous dispersion (the decrease in refractive index which is associated with absorption) can be used to produce a phase-matched condition for second harmonic generation. This process also gives rise to large increases in the useful second order hyperpolarizability. A new, soluble NLO dye with exceptionally low absorption near 400 nm has been used for anomalous dispersion phase-matching studies in thin films.
The weldability of alloys based on Ni{sub 3}Al and Fe{sub 3}Al is discussed. Both of these ordered alloy systems may experience problems associated with welding. In the case of Ni{sub 3}Al alloys, limited hot ductility contributes to heat-affected zone cracking. Fe{sub 3}Al alloys experience similar difficulties in zone cracking. Fe{sub 3}Al alloys experience similar difficulties in welding due to excessive grain embrittlement due to the presence of water vapor. Advances in both alloying and substructural refinement to improve the weldability are reviewed. 18 refs., 10 figs.
Methods of preparing non-agglomerated powders for three systems -- yttria, titania, and yttria-stabilized zirconia -- are reviewed. The non-agglomerated nature of these powders should make it possible to sinter them into dense ceramic bodies with nanocrystalline grain sizes. Experiments with yttria-stabilized zirconia have shown that this is indeed the case, with mean linear intercept grain sizes of 60 nm resulting from original powder particle diameters of 13 nm. This ultrafine-grained zirconia is shown, in turn, to have superplastic forming rates 34 times faster than a 0.3 {mu}m-grained commercial zirconia of the same composition. 7 refs., 9 figs.
The first commercially available GaAs 8K ROM has been designed and manufactured using GigaBit Logic's 3-level metal E/D process. The worst case clock frequency of 650 MHz has been obtained with a power dissipation of 3.5 W. The ROM is organized as 1K X 8 bits, and on-chip translation logic enables the ROM to have an effective 4K X 8 resolution when used a a sine look-up table. The ECL compatible ROM is packaged in GigaBit Logic's standard 40 pin package.
Lienert, T.J.; Robino, C.V.; Hills, C.R.; Cieslak, M.J.
The weldability, solidification behavior, and solidification microstructures of Hastelloy{asterisk} Alloy B-2 and Hastelloy{asterisk} Alloy W have been investigated. Susceptibility to fusion zone hot-cracking was determined by autogenous Varestraint testing. High temperature phase transformations, including solidification events, were identified by differential thermal analysis (DTA). After testing, the microstructures of various specimens were examined by optical metallography, scanning electron microscopy (SEM), electron microprobe analysis, and analytical electron microscopy (AEM). Results of this study showed that Hastelloy B-2 has exceptional resistance to hot cracking, comparable to that of Hastelloy C-4 and 304 stainless steel, while Hastelloy W proved to be somewhat more susceptible to hot cracking, exhibiting behavior similar to Alloy 625. The solidification process in both Hastelloy B-2 and Hastelloy W was found to be dominated by the segregation of Mo which gives rise to the formation of terminal eutectic-like constituents. This pattern of segregation is consistent with that of previous work on other Ni--Mo--Cr alloys. The microstructural constituents associated with hot-cracking in each alloy have been identified. 13 refs., 8 figs.
The weldability of Haynes {reg sign} Alloy No. 242 {trademark}, a new alloy derived from the Ni-Mo-Cr system, was investigated. Susceptibility to fusion zone hot cracking was determined by Varestraint testing, and hot ductility was characterized by Gleeble testing. Solidification phase transformation data was recorded with differential thermal analysis (DTA). Weld microstructures were characterized with scanning electron microscopy (SEM), analytical electron microscopy (AEM), and electron probe microanalysis (EPMA). The results of this study indicate that this alloy has better hot cracking resistance than high strength nickel base superalloy 718; however, it has lower resistance than other alloys derived from the Ni-Cr-Mo ternary such as the Hastelloy alloys B2, C-4, C-22, C-276, and W. Segregation patterns in weld microstructures agree well with established information concerning this family of alloys. Prediction of solidification products with the Ni-Mo-Cr phase diagram based on a chemical equivalence was unsuccessful due to the higher carbon content of this alloy which favors the formation of M{sub 6}C. Solidification in Alloy 242 terminates with the formation of two eutectic-like constituents: (1) a M{sub 6}C/austenite eutectic, and (2) a second eutectic with austenite and an undetermined phase. This latter phase has a composition similar to the M{sub 6}C phase, but with a different crystal structure (cubic, ao = 6.6 {Angstrom}). 11 refs., 10 figs., 4 tabs.
In the Recirculating Linear Accelerator, we will inject a 10-kA to 20-kA electron beam, and then focus and guide it with an IFR plasma channel, which is created with a low energy electron beam. The REB will be transported through a closed racetrack or a spiral beam line to be re-accelerated by the ringing waveform of dielectric cavities. By adding more accelerating cavities along the beam line, high energies can be achieved. Experiments are in progress to study IFR beam transport issues. A new injector is needed for beam re- acceleration experiments. We are presently installing this new REB injector which will-provide a higher amplitude ({approximately}4 MV), longer duration ({approximately}40-ns FWHM), more rectangularly shaped({approximately}25-ns full width at 90% peak) waveform and a colder beam than were achievable with the previous 1.5-MV injector. The resultant constant beam energy can be more efficiently matched the guiding IFR plasma channel in the beam line and to the turning section magnetic fields. We are now developing new cavities that produce accelerating voltage pulses with improved waveform flatness, width, and amplitudes that do not suffer unacceptable degradation over the first four ringing periods. This effort requires network solver and electrostatic field stress analysis computer codes, and a scaled test model to compare actual waveforms to those predicted by the simulations. 10 refs., 9 figs.
Prior research has concentrated on damage at the Si--SiO{sub 2} interface caused by photoinjection of electrons into the oxide by near UV light. The damage processes involved may be similar to those responsible for degradation in the Stanford type, point contact solar cell (PCSC). 7 refs., 6 figs.