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To increase the reliability of the criticality monitoring system in a diagnostic chemistry area and to reduce the number of false alarms, a new monitoring system was built using a fast-neutron detector. This paper outlines the design requirements, describes the plastic scintillation detector system as it was built, and reports on the results of several months of operation. The new monitor has proven much more useful than the gamma-detector system it replaced.

This research demonstrates the feasibility of using homogeneously-generated fission fragments to simulate high-fluence fusion neutron damage in niobium tensile specimens. This technique makes it possible to measure radiation effects on bulk mechanical properties at high damage states, using conveniently short irradiation times. The primary knock-on spectrum for a fusion reactor is very similar to that produced by fission fragments, and nearly the same ratio of gas atoms to displaced atoms is produced in niobium. The damage from fission fragments is compared to that from fusion neutrons and fission reactor neutrons in terms of experimentally measured yield strength increase, transmission electron microscopy (TEM) observations, and calculated damage energies.

Plasma generated in low-density vapor by a negative ion beam has been studied experimentally and computationally. We show that space charge neutralization of the beam occurs at very low vapor density, and that correspondingly the electron density may be much less than the beam and plasma ion densities. When there is a large local gas density, as in a charge changing cell, the resulting high electron density is also localized to the same region. Therefore, very few electrons will reach a negative ion accelerator even if it is placed one or two beam diameters from such a cell.

As indicated by tests on several cameras, the dynamic range of the Lawrence Livermore Laboratory streak-camera system appears to be about two orders of magnitude greater than those reported for other systems for 10- to 200-ps pulses. The lack of a fine mesh grid in the RCA streak tube used in these cameras probably contributes to a lower system dynamic noise and therefore raises the dynamic range. A developmental tube with a mesh grid was tested and supports this conjecture. Order-of-magnitude variations in input slit width do not affect the spot size on the phosphor or the dynamic range of the RCA tube.

We have developed processes for mass producing the quality glass microspheres required for current laser fusion experiments. We describe the advances in the methods and materials used in our liquid droplet and dried gel systems.

A Mach-Zehnder interference microscope was automated which quickly characterizes and sorts transparent microspheres. It takes only 12 seconds to measure a 3 micron thick glass microsphere.

The Spent Fuel Test-Climax is a test of retrievable storage in granite of spent nuclear reactor fuel. The rock has been instrumented to measure temperatures, stress changes, and displacements. Periodic tape extensometer readings provide test drift convergence data. Vertical and horizontal tape readings are made at five locations in each of two 3.4m x 3.4m (11 ft x 11 ft) drifts and six locations in a 4.6m x 6.2m (15 ft x 20.5 ft) drift. The sensitivity of the readings to temperature effects, errors in temperature corrections, change of steel tape, and change of operator has been examined. Calculated corrections for temperature-induced changes in distance range from 0.001 in. to 0.003 in.//sup 0/C. A tape changeout evidenced both a systematic error apparently due to slight changes in tape registration during punching and to nonidentical location of punched holes in the two tapes and a random error due to variability of reading and punching operations. These errors were corrected by making duplicate measurements for the tapes. Tape readings by the same operator have been repeatable within +-0.001 in. in the smaller drifts and +-0.002 in. in the larger. Different operators have been able to repeat readings to within +-0.004 in. (usually …

The results of recent numerical simulations of supernova explosions are presented and a variety of topics discussed. Particular emphasis is given to (i) the nucleosynthesis expected from intermediate mass (10sub solar less than or equal to M less than or equal to 100 Msub solar) Type II supernovae and detonating white dwarf models for Type I supernovae, (ii) a realistic estimate of the ..gamma..-line fluxes expected from this nucleosynthesis, (iii) the continued evolution, in one and two dimensions, of intermediate mass stars wherein iron core collapse does not lead to a strong, mass-ejecting shock wave, and (iv) the evolution and explosion of vary massive stars (M greater than or equal to 100 Msub solar of both Population I and III. In one dimension, nuclear burning following a failed core bounce does not appear likely to lead to a supernova explosion although, in two dimensions, a combination of rotation and nuclear burning may do so. Near solar proportions of elements from neon to calcium and very brilliant optical displays may be created by hypernovae, the explosions of stars in the mass range 100 M/sub solar/ to 300 M/sub solar/. Above approx. 300 M/sub solar/ a black hole is created by stellar …

Waste management has reached paramount importance in recent years. The successful management of radioactive waste is a key ingredient in the successful operation of any nuclear facility. This paper discusses the options available for on-site storage of low-level radioactive waste and those options that have been selected by the Department of Energy facilities operated by Martin Marietta Energy Systems, Inc. in Oak Ridge, Tennessee. The focus of the paper is on quality assurance (QA) features of waste management activities such as accountability and retrievability of waste materials and waste packages, retrievability of data, waste containment, safety and environmental monitoring. Technical performance and careful documentation of that performance are goals which can be achieved only through the cooperation of numerous individuals from waste generating and waste managing organizations, engineering, QA, and environmental management.

This paper contains viewgraph material assessing the density limits and fueling limits of different thermonuclear devices. Various density limits are considered with emphasis on the Murakami limit and the Hugill limit. (GSP)

Results are presented from tests of the third full scale development dipole magnet for the Superconducting Super Collider and from a retest of a 4.5 m model magnet of the same design mounted in an SSC cryostat. The 4.5 m magnet shows consistent quench performance between its original tests in boiling liquid helium in a vertical dewar and the current tests in forced flow helium in a horizontal cryostat. Little or no retraining is observed over several thermal cycles. The full length magnet requires 12 quenches to train to its short sample limit of 6800 A and displays a reasonably stable quench plateau following training. This represents a great improvement over the performance of the first two full length magnets. Data are presented on quench behavior as a function of current and temperature and on azimuthal and longitudinal loading of the coil by the support structure. 14 refs., 7 figs.

A computational modeling code (EQPSreverse arrowS) has been developed to examine sulfur isotopic distribution pathways coupled with calculations of chemical mass transfer pathways. A post processor approach to EQ6 calculations was chosen so that a variety of isotopic pathways could be examined for each reaction pathway. Two types of major bounding conditions were implemented: (1) equilibrium isotopic exchange between sulfate and sulfide species or exchange only accompanying chemical reduction and oxidation events, and (2) existence or lack of isotopic exchange between solution species and precipitated minerals, parallel to the open and closed chemical system formulations of chemical mass transfer modeling codes. All of the chemical data necessary to explicitly calculate isotopic distribution pathways is generated by most mass transfer modeling codes and can be input to the EQPS code. Routines are built in to directly handle EQ6 tabular files. Chemical reaction models of seafloor hydrothermal vent processes and accompanying sulfur isotopic distribution pathways illustrate the capabilities of coupling EQPSreverse arrowS with EQ6 calculations, including the extent of differences that can exist due to the isotopic bounding condition assumptions described above. 11 refs., 2 figs.

In August 1987, a routine Ames test on soot from the Lawrence Livermore National Laboratory (LLNL) 4-in. gun showed that the soot was mutagenic to Salmonella bacteria. Subsequent liquid chromatography on the soot showed that, out of hundreds of ultravoilet-absorbing compounds found in the residue, only three or four were mutagenic. When a sample large enough to weigh was collected, it was found that No environmentally identified complex mixture has ever been reported with as much Ames/Salmonella activity per gram as the gun residues.'' Since then, Ames tests of hundreds of samples have verified that the residues from our gun tanks may be hazardous to health. The actual degree of the hazard and the identity of the offending chemicals are still unknown. 2 refs.

High performance Ti-alloyed internal-Sn superconductors have been selected for use in the Proof of Principles (PoP) coil, and a 1.0 m o.d., 0.4 m i.d., solenoid designed to produce fields up to 15 T. The PoP coil, which will use forced-flow Cable-In-Conduit Conductors (CICC), will operate at 4.2 K and moderate levels of conductor strain. Here we report the results of detailed characterizations of two proposed PoP coil Nb{sub 3}Sn 19 subelement superconductor wires of different topology. We have investigated the critical current as a function of applied field, and applied strain. The wires were found to have excellent high field properties, providing a high performance margin for the proposed PoP coil. The field and strain dependence of J{sub c} have been found to compare favorably with predictions from a wire performance model recently developed for Nb{sub 3}Sn superconductors. 5 refs., 6 figs., 2 tabs.

The quenching and stability behavior of forced-flow helium-cooled, cable-in-conduit conductors (CICC) has been analyzed using a new computer program. This computer analysis code was developed for performing general, transient, thermal analyses on CICCs. The program includes the necessary details for the physical properties of all the constituent materials of such conductors, and accurately models the thermo- and fluid-dynamic behavior of the helium coolant starting from a wide range of initial conditions. It has been applied to a study of the stability and quench behavior of several large-scale conductor options being considered for use in the magnet systems of the International Thermonuclear Experimental Reactor (ITER), and the results will be reported here. 3 refs., 14 figs.

Conceptual design of the International Thermonuclear Experimental Reactor (ITER) superconducting magnet system is nearing completion by the ITER Design Team, and one of the Central Solenoid (CS) designs is presented. The CS part of this magnet system will be a vertical stack of eight modules, approximately 16 m high, each having a approximate dimensions of: 4.1-m o.d., 2.8-m i.d., 1.9-m h. The peak field at the bore is approximately 13.5 T. Cable-in-conduit conductor with Nb{sub 3}Sn composite wire will be used to wind the coils. The overall coil fabrication will use the insulate-wind-react-impregnate method. Coil modules will be fabricated using double-pancake coils with all splice joints located in the low-field region on the outside of the coils. All coils will be structurally graded with high-strength steel reinforcement which is co-wound with the conductor. We describe details of the CS coil design and analysis.

The Fusion ENgineering International eXperimental (FENIX) Test Facility which is nearing completion at Lawrence Livermore National Laboratory, is a 76-t set of superconducting magnets housed in a 4-m-diameter cryostat. It represents a significant step toward meeting the testing needs for the development of superconductors appropriate for large-scale magnet applications such as the International Thermonuclear Experimental Reactor (ITER). The magnet set is configured to allow radial access to the 0.4-m-diameter high-field region where maximum fields up to 14 T will be provided. The facility is fitted with a thermally isolated test well with a port to the high-field region that allows insertion and removal of test conductors without disturbing the cryogenic environment of the magnets. It is expected that the facility will be made available to magnet developers internationally, and this paper discusses its general design features, its construction, and its capabilities.

Conductors designed for fusion machines must operate at high fields, under large mechanical loads, and in a high neutron flux. Present designs favor the use of Nb{sub 3}Sn with force-cooling by supercritical helium to extract large nuclear and ac loss heat loads. Consequently, the magnet designer must have a good knowledge of the critical current of the superconductor as a function of field, strain, temperature, and radiation damage. Expanding on work by Hampshire, et al. and Ekin, combined with radiation damage studies of Nb{sub 3}Sn, we express the critical field (B{sub c20}) as function of temperature, strain and damage energy (E{sub d}). Similarly, the zero-field critical temperature (T{sub c0}) is expressed as a function of strain and damage energy. The expressions of B{sub c20} and T{sub c0} are combined into a functional form that allows an accurate and consistent estimate of the critical current density at the operating conditions of fusion magnet conductors. 9 refs., 4 figs.

This work describes the development and testing of a new method for the separation and analysis of most actinides of interest in environmental samples. It combines simplified extraction chromatography using highly selective absorption resins to partition the individual actinides with the measurement of their alpha activities by liquid scintillation spectrometry. The liquid scintillation counting technique pioneered by McDowell proved useful in determination of alpha emitting radionuclide in a wide variety of matrices. Alpha emitters are chemically extracted into an organic phase which also contains the scintillation cocktail. Oxygen is purged from the solution to improve the energy resolution of the measurement and the counting sample is sealed in a small glass tube for assay. The Photon-Electron Rejecting Alpha Liquid Scintillation (PERALS{trademark}) Spectrometer provides high counting efficiency, low background, pulse shape discrimination for photon/electron/{beta} particle rejection and moderate energy resolution in a compact package. Chemical extraction/liquid scintillation counting significantly reduces the extensive chemical purification and electroplating required for conventional alpha spectrometry with semiconductor detectors. PERALS{trademark} analyses have been used routinely for quickly surveying suspect samples and determining the source of unknown alpha activities.

We present the results of a series of experiments to measure the thermal recovery times of a flashlamp-pumped, Nd:Glass multi-segment laser amplifier. In particular, we investigated the thermal recovery times under the following cooling options: (1) passive cooling; (2) active cooling of the flashlamp cassettes, and (3) active cooling of the flashlamp cassettes and gas flow in the pump cavity.

The conceptual design of the National Ignition Facility (NIF) 192 beam laser incorporates a low-power alignment beam injected in the pinhole plane of the final spatial filter with a wave length intermediate between the 1053 mn laser output and the 351 mn frequency-converted beam that illuminates the target Choosing the specific wavelength for which the spatial filter plane is reimaged in the same target chamber plane as the frequency-converted main laser pulse, achieves optimum accuracy without the need for additional means to insure precise overlap between the two beams. Insertion of the alignment beam after the last laser amplifier also allows alignment to the target while the amplifiers are still cooling from a previous shot.

In this paper, we present the direct spatial measurement of the two-dimensional gain profiles for the Ne-like Ge 196 Å laser line using a slab target illuminated by the multiple pulse technique. To understand the spatial dependence for Ge plasmas driven by a series of 100 ps pulses 400 ps apart we did a series of Nova experiments backlighting short Ge amplifiers. Two-dimensional, high-resolution, spatial images of the 196 Å laser emission from the output aperture of the amplifiers were measured to determine the spatial position of the gain. The amplifier lengths were chosen to be short enough to avoid the significant refraction effects which have dominated the analysis of previous near field imaging experiments. To assure good temporal overlap, the traveling wave geometry was used to illuminate both the amplifier and backlighter. The amplifier design included a wire fiducial that provided an absolute spatial reference and avoided the usual difficulty of determining the location of the target surface. We compare the measured spatial gain profiles with simulations done using LASNEX, which calculates the hydrodynamic evolution of the plasma, and XRASER, which uses the temperatures and densities from LASNEX to do the gain and kinetics calculations.

The polymer electrolyte fuel cell (PEFC) is the primary candidate as the power source for light-duty transportation systems. On-board conversion of fuels (reforming) to supply the required hydrogen has the potential to provide the driving range that is typical of today's automobiles. Petroleum-derived fuels, gasoline or some distillate similar to it, are attractive because of their existing production, distribution, and retailing infrastructure. The fuel may be either petroleum-derived or other alternative fuels such as methanol, ethanol, natural gas, etc. [1]. The ability to use a variety of fuels is also attractive for stationary distributed power generation [2], such as in buildings, or for portable power in remote locations. Argonne National Laboratory has developed a catalytic reactor based on partial oxidation reforming that is suitable for use in light-duty vehicles powered by fuel cells. The reactor has shown the ability to convert a wide variety of fuels to a hydrogen-rich gas at less than 800 C, temperatures that are several hundreds of degrees lower than alternative noncatalytic processes. The fuel may be methanol, ethanol, natural gas, or petroleum-derived fuels that are blends of various hydrocarbons such as paraffins, olefins, aromatics, etc., as in gasoline. This paper will discuss the results obtained …