Superconducting magnet systems under construction and projected for the future contain magnets that are magnetically coupled and electrically connected with shared power supplies. A change in one power supply voltage affects all of the magnet currents. A current controller for these system must be designed as a multivariable system. The power describes a method, based on decoupling control, for the rational design of these systems. Dynamic decoupling is achieved by cross-feedback of the measured currents. A network of gains at the input decouples the system statically and eliminates the steady-state error. Errors are then due to component variations. The method has been applied to the magnet system of the MFTF-B, at the Lawrence Livermore National Laboratory.

On November 16, 1984 a leak was discovered in one of the Fast Flux Test Facility (FFTF) Primary Sodium Sampling System electromagnetic pumps. The leak was discovered in the course of routine cell entry to investigate a shorted trace heat element. The purpose of this paper is to describe the circumstances surrounding the occurrence of the leak, the actions taken to replace the damaged pump and the additional steps which were necessary to return the plant to power. In addition, the processes involved in producing the leak are described briefly. The relative ease of recovery from this incident is indicative of the overall feasibility of the Liquid Metal Reactor (LMR) operational concept.

Superconducting magnet systems under construction and projected for the future contain magnets that are magnetically coupled and electrically connected with shared power supplies. A change in one power supply voltage affects all of the magnet currents. A current controller for these systems must be designed as a multivariable system. The paper describes a method, based on decoupling control, for the rational design of these systems. Dynamic decoupling is achieved by cross-feedback of the measured currents. A network of gains at the input decouples the system statically and eliminates the steady-state error. Errors are then due to component variations. The method has been applied to the magnet system of the MFTF-B, at the Lawrence Livermore National Laboratory.

To better understand and predict tandem-mirror experiments, we are building a comprehensive Mirror Equilibrium Radial Transport and Heating (MERTH) code. In this paper we first describe our method for developing the code. Then we report our plans for the installation of physics packages for electron- and ion-cyclotron heating of the plasma.

The activation of five structural materials and seven coolant/breeder/multiplier materials in a common reference neutron environment was calculated with the FORIG activation code. The reference environment was the neutron flux and spectrum at the first wall of the mirror advanced reactor study (MARS) reactor. Qualitative comparison of these activated materials were made with respect to worker protection requirements for gamma radiation in handling the materials and with respect to their classifications for near-surface disposal of radioactive waste.

The axial ion plugging potential in a tandem mirror is produced by electron cyclotron resonance heating (ECRH) applied at two locations in the end mirror cell. A second harmonic (..omega.. = 2..omega../sub c/) resonance is used near the midplane to generate hot electrons which yield an electron potential barrier between center cell electrons and electrons outboard of the end cell midplane. The latter group of electrons is then heated at the fundamental resonance (..omega.. = ..omega../sub c/) on the outboard side of the magnetic well which drives an ion confining potential. Fokker-Planck and Monte Carlo calculations show that such a configuration is achievable, and the scaling obeys a rather simple set of equations. Another aspect of this configuration is the experimental observation that the fundamental heating drives the overall potential of the device relative to the wall to approx. 1 kV. An analytic model predicts this behavior for very strong ECRH. Results are given a numerical study of electron confinement in a mirror cell owing to fundamental heating as the level of the rf electric field, E/sub rf/, is increased. For the second part of the paper, we show that moderate levels of uniformly distributed rf fields, called cavity fields, …

Atomic vapor laser isotope separation (AVLIS) is a general and powerful technique. A major present application to the enrichment of uranium for light-water power reactor fuel has been under development for over 10 years. In June 1985 the Department of Energy announced the selection of AVLIS as the technology to meet the nation's future need for the internationally competitive production of uranium separative work. The economic basis for this decision is considered, with an indicated of the constraints placed on the process figures of merit and the process laser system. We then trace an atom through a generic AVLIS separator and give examples of the physical steps encountered, the models used to describe the process physics, the fundamental parameters involved, and the role of diagnostic laser measurements.

Experimental spectroscopy data of fission products have been obtained using highly automated and rapid chemical separations followed by automated spectroscopy studies of isolated fission products. These data have established the presence of only a single level with spin-parity of 1/sup +/ below 1500 keV of excitation in Z = 51 /sup 132/Sb/sub 81/. This is in contrast to the results of our studies of /sup 130/Sb and /sup 134/I. For /sup 134/I, the N = 81 isotone with Z = 53, we can characterize three 1/sup +/ levels below 1200 keV. For /sup 130/Sb/sub 79/ that has a neutron pair less than /sup 132/Sb, we can identify two 1/sup +/ levels below 1100 keV. We can account for the additional levels using the LLNL shell-model code which is based on the Lanczos tridiagonalization algorithm using an uncoupled m-scheme basis and vector manipulations. The 1g/sub 7/2/, 2d/sub 5/2/, 2d/sub 3/2/, 1h/sub 11/2/, and 3s/sub 1/2/ orbitals are available to the valence protons and the 2d/sub 5/2/, 2d/sub 3/2/, 1h/sub 11/2/, and 3s/sub 1/2/ orbitals are available to the valence neutron holes. Analysis of the wavefunctions show the dominant role of three nucleon cluster configurations in producing the increased number of states …

Fission reactors can be used to conduct some of the fusion nuclear engineering tests identified in the FINESSE study. To further define the advantages and disadvantages of fission testing, the technical and programmatic constraints on this type of testing are discussed here. This paper presents and discusses eight key issues affecting fission utilization. Quantitative comparisons with projected fusion operation are made to determine the technical assets and limitations of fission testing. Capabilities of existing fission reactors are summarized and compared with technical needs. Conclusions are then presented on the areas where fission testing can be most useful.