Current plans for nuclear waste disposal include placing the waste in a canister to isolate it from the repository environment for 1000 years. Corrosion prediction techniques are currently inadequate to quarantee the canister performance over this length of time. We are attempting to better predict the corrosion process with the help of computer modeling. We developed a program to calculate anodic and cathodic polarization curves using Tafel slopes, equilibrium exchange current densities, and other electrochemical parameters obtained from the experimental corrosion literature. The model generates and displays polarization curves for different values of environmetal parameters such as temperature, pH, and concentrations of pertinent species in the vicinity of the canister material. For the case of uniform corrosion in acidic media, our model predicts corrosion rates in fair agreement with literature values.

The giant dipole (GD) parameters of peak energy, width, and cross section were satisfactorily correlated for elements from V to Bi, assuming two overlapping peaks with a separation dependent on deformation. The energy dependence of the GD resonance is assumed to have a Breit-Wigner form, but with an energy-dependent width. The resulting gamma-ray strength function model is used to predict neutron capture cross sections and gamma-ray spectra for isotopes of Ta, Os, and Au. 23 references.

Large laser systems require numerous laser diagnostics to provide configuration, performance and maintenance data to permit efficient operation. The following diagnostics for a large laser system named Shiva are discussed: (1) description of Shiva laser system, (2) what measurements are desired and or required and why, (3) what measurement techniques and packages are employed and a brief description of the operating principles of the sensors employed, and (4) the laser diagnostic data acquisition and display system.

Filtered x-ray diode detectors were used to measure absolute x-ray spectra below 1.5 keV at the Lawrence Livermore Laboratory Argus and Shiva laser facilities. We use K or L-edge filters in five and ten channel arrays to obtain energy resolution between 200 eV and 1.5 keV with channel FWHM's typically 200 eV. A channel with relatively uniform energy response is employed to independently measure the total x-ray energy up to 1.5 keV. Filter transmissions and detector sensitivities are measured absolutely to within +- 10% and +- 20% respectively at Lawrence Livermore Laboratory. With a FWHM time response that is less than 180 ps, the windowless diode detector developed for our experiments does not contribute significantly to system time response. Most of the fast oscilloscopes that we use for recording signals have a FWHM of 300 or 700 ps. We present, as examples, some ten channel x-ray spectral results obtained for disk irradiations at the Argus 1.06 micron laser facility.

Described is a computer-based gamma ray spectrometer system using a germanium detector for rapid nondestructive measurement of isotopic and total plutonium concentrations in solutions at nuclear reprocessing plants. Isotopic concentrations have been measured with an accuracy of +-0.5%. Cell design, calibration techniques, and preliminary results are discussed. This system is being installed at the Tokai reprocessing plant in Japan.

We have done a series of one- and two-dimensional calculations of hard-core Z-pinch flux compression experiments in order to study the effect of a plasma on these systems. These calculations show that including a plasma can reduce the amount of flux lost during the compression. Flux losses to the outer wall of such experiments can be greatly reduced by a plasma conducting sheath which forms along the wall. This conducting sheath consists of a cold, dense high ..beta.., unmagnetized plasma which has enough pressure to balance a large field gradient. Flux which is lost into the center conductor is not effectively stopped by this plasma sheath until late in the implosion, at which time a layer similar to the one formed at the outer wall is created. Two-dimensionl simulations show that flux losses due to arching along the sliding contact of the experiment can be effectively stopped by the formation of a plasma conducting sheath.

Two methods for measuring the leach rates of simulated high level waste glass are compared. One is a modification of the standard IAEA method and the other is a one-pass method in which fresh leachant solution is pumped over the sample at a controlled flow rate and temperature. For times up to 3 days, there is close agreement between results from the two methods at 25.0/sup 0/C. Leach rates from the one-pass method show a correlation with flow rate only on day 1 at 25.0/sup 0/C, whereas they show a correlation with flow rate for all three days at 75.0/sup 0/C. /sup 237/Np rates at 75.0/sup 0/C are greater than those at 25.0/sup 0/C, but /sup 239/Pu rates at 75.0/sup 0/C are less than or equal to those at 25.0/sup 0/C.

Four years of experience with on-line monitoring of a large autoclave used primarily for forming bonds and material densification is reported. The purpose of this work is to confirm that no flaws are growing in the autoclave during operation. Failure of this device during operation could endanger personnel and would damage property. Its loss would seriously curtail several ongoing research efforts. The vessel is monitored with a commercial minicomputerized flaw location system. Four 4-sensor arrays are attached to the exterior of the device to receive acoustic emission signals. Computed locations are stored on cassette tape and selected portions can be displayed on a cathode ray screen. It is shown that although the minicomputer is implemented with two dimensional location software, the information can be reprocessed in a central computer to produce locations in three dimensions. Long term storage of data, data display, noise analysis, calibration, and computerized location error analysis is discussed. No degradation by flaw growth has been detected in the device to date. This is the expected result, since it has an estimated 30-y life.

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Reliable performance of fuels for the Fast Flux Test Facility (FFTF) is of paramount importance for the FFTF program. Improved inspection techniques and processes are essential for controlling the quality of such fuels. Several considerations necessitated the development and application of improved inspection techniques and processes. These include fuel design, throughput rate, and pre-irradiation characterization requirements. Some of the more significant advances are in the areas of fuel pellet dimensional and weight measurements, fuel pin diameter measurements, and on-line, computerized quality status tracking. Advances in each of these areas are discussed.

The use of ab initio molecular orbital calculations to aid in the characterization, i.e., structures and energies, of metal halide complexes present in high temperature salt vapors has been investigated. Standard LCAO-SCF methods were used and calculations were carried out using the minimal STO-3G basis set. The complexes included in this study were Al/sub 2/F/sub 6/, Al/sub 2/Cl/sub 6/, AlF/sub 3/ NH/sub 3/, AlCl/sub 3/ NH/sub 3/, and AlF/sub 3/ N/sub 2/. The Al/sub 2/X/sub 6/ complexes are found to have D/sub 2h/ symmetry in agreement with most experimental results. A planar form was found to be considerably higher in energy. The AlX/sub 3/ NH/sub 3/ complexes are found to have C/sub 3v/ symmetry with a small barrier to rotation about the Al-N axis. The AlF/sub 3/ N/sub 2/ complex is found to be weakly bound together with a binding energy of -8.2 kcal/mole at the STO-3G level.

An automated facility remotely and automatically analyzes soil, water, and sediment samples for uranium. The samples travel through pneumatic tubes and switches to be first irradiated by neutrons and then counted for resulting neutron and gamma emission. Samples are loaded into special carriers, or rabbits, which are then automatically loaded into the pneumatic transfer system. The sample carriers have been previously coded with an identification number, which can be automatically read in the system. This number is used for correlating and filing data about the samples. The transfer system, counters, and identification system are controlled by a network of microprocessors. A master microprocessor initiates routines in other microprocessors assigned to specific tasks. The software in the microprocessors is unique for this type of application and lends flexibility to the system.

Four unique deisgn features are described which make the Fast Flux Test Facility eminently suitable for irradiation test programs. These features are a fast flux level of 7 x 10/sup 15/ neutrons/cm/sup 2//sec, a 36-inch reference (breeder reactor) core height, test volumes suitable for testing of statistical quantities of materials, and the capability for direct (contact) or indirect (proximity) instrumentation of active core experiments.

Induced radioactivity in the blanket and other parts of a fusion reactor close to the plasma zone will dictate remote assembly, disassembly, and maintenance procedures. Time will be of the essence in these procedures. They must be practicable and certain. This paper discusses the reduction of a complicated Tokamak reactor to a simpler assembly via the use of a vacuum building in which to house the reactor and the introduction in this new model of cassette blanket modules. The cassettes significantly simplify remote handling.

Gamma-ray spectrometric methods using high-resolution Ge(Li) and high purity Ge detectors have been used to quantify the concentrations and external exposure rates of radionuclides in the soil. These in situ methods have been used to study radionuclide deposition around nuclear power stations, the distribution of radionuclides at the Nevada Test Site, biogeochemical cycling of radionuclides, and the fate and impact of fallout radionuclides. Portable gamma-ray spectrometer systems used for various kinds of in situ field measurements include: large-volume coaxial Ge(Li) detectors for terrestrial gamma-ray surveys at several sites including preoperational nuclear power plants and for real-time measurements of nuclear reactor plume isotopic exposure rates; and planar, high purity Ge detectors for mapping /sup 241/Am and /sup 239/Pu soil concentrations, particularly at the Nevada Test Site. These applications are discussed along with a brief description of the methodology and techniques associated with in situ gamma-ray spectrometry.

Stress corrosion tests were conducted on 316 VIM/VAR stainless steel as part of the Tritium Facility's Quality Assurance Program. Initial results under severe conditions indicate earlier-than-expected failure. We are expanding our tests to further examine this problem.

A calculation is presented for the final bunching of a particle beam in a synchrotron or storage ring. The voltage per turn, the harmonic number, and the bunching time are obtained. (PMA)

This paper discusses the current status of reactor design for heavy ion fusion.

A 25 megajoule, 20 kV capacitive energy storage and delivery system has been built and tested for Shiva--a 20 arm, 10 kJ, 20 TW neodymium glass fusion research laser. This system supplies over 3.5 megamperes to xenon flashlamps for optical pumping of the laser amplifier. About 15% of the energy is used to establish magnetic fields within Faraday rotator glass. A digital based control and diagnostics scheme is employed through the entire pulse power system. This scheme utilizes a distributed digital data bus that addresses every element through two levels of optical isolation. The interfacing of low level digital circuitry to a pulse power environment is discussed, as well as the design and performance of the total system. Cost and manufacturing details are important in a project of this size. The projected cost goal of 27 cents/joule, installed and operating, has been met. The general approach to the design, transient analysis, manufacture, and activation of this large power conditioning system is also discussed.

There is a great deal of experimental evidence associating selective bond breaking ability with low coordination number surface sites on transition metal surfaces. Atomic steps break H-H and C-H bonds efficiently while kinks in the steps are required for additional C-C and C=O bond scissions. The blockage of some of the ''active sites'' yields the reaction selectivity commonly observed as a result of alloying or upon introduction of certain promoters. Another important parameter in controlling transition metal catalytic activity is the formal oxidation state of the surface metal atom. Oxidation of the surface atoms by oxygen or halogens or their reduction by electron donors (carbon, alkali metals, etc.) changes markedly the catalytic surface chemistry. H/sub 2/-D/sub 2/ exchange, hydrocarbon conversion reactions and the hydrogenation of CO are examples to demonstrate the importance of low coordination number sites and surface oxidation state in controlling catalytic activity and selectivity.

To meet neutral-beam source requirements, a combination series switch/regulator system has been developed that can provide up to 40-kV at 80A output for 10-ms from the continuously decaying voltage of a charged capacitor bank. The system uses 100% feedback control of a series hard tube regulator. This feedback regulator is able to maintain a 40-kV output level for 100% load variations while the source voltage for the capacitor bank is drained from an initial 55-kV down to as low as 43-kV during a 10-ms pulse. In addition to controlling the output voltage, the series regulator tube also serves the dual role of a disconnect or interrupt switch at the end of each pulse and during the frequent occurrence of a neutral-beam source fault. In the interrupt mode, complete disconnect is achieved in less than 2-..mu..s after first observance of a fault condition; recovery times to normal operation of less than 10-..mu..s after fault clearance can be attained if desired.

When the plasma outflow velocity relative to the critical surface is supersonic, compressional density profiles can form in the critical region. These compressions involve dissipative processes like those in collisionless shocks; associated plasma instabilities and reflected ions may inhibit energy transport and enhance laser light absorption.

Preliminary design and performance test results for fast optical shutters intended for use in the Nova high power fusion laser system are briefly described. Both an opening shutter to protect the pellet target from amplified spontaneous emission (ASE), and a closing shutter to protect the laser from light reflected back from the target are discussed. Faraday rotators, synchronized by a 400 Hz oscillator, provide an opening shutter mechanism with an opening time of approximately 10 ..mu..s. A plasma closing shutter, employing electrical sublimation of a foil, provide a shutter closing time of 70 ns +- 20 ns. Energy for foil sublimation is provided by discharge of a 42 J capacitor bank. Implementation of these shutter techniques in the Nova system is anticipated to improve laser output power and efficiency. (RME)

This paper describes the Fiber Optic Telemetry System designed to operate in the hostile particle and electromagnetic radiation environment of the High Voltage Test Stand. It discusses system criteria, components, packaging, and performance. In all tests to date, the system exceeds its design goals with very comfortable margins. It is well advanced into the fabrication stages with all crucial components tested and only straightforward TTL (Transistor Transistor Logic) circuitry to be completed.