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.

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.

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.

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.

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.

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.

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.

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.