The gas release behavior of irradiated EBR-II fuel was observed to be dependent on several factors: the presence of cladding, the retained gas content, and the energy absorbed. Fuel that retained in excess of 16 to 17 ..mu..moles/g of fission gas underwent spallation as the cladding melted and released 22 to 45% of its retained gas, while fuel with retained gas levels below approx. 15 to 16 ..mu..moles/g released less than approx. 9% of its gas as the cladding melted. During subsequent direct electrical heating ramps, fuel that did not spall released an additional quantity of gas (up to 4 ..mu..moles/g), depending on the energy absorbed.

Born to meet the special needs of America`s space effort, the SP-100 Program testifies to the cooperation among government agencies. The Department of Energy (DOE), the National Aeronautics and Space Administration (NASA), and the Defense Advanced Research Projects Agency (DARPA) are working together to produce a 100-kW power system for use in outer space. At this point in the effort, it is appropriate to review: The approach to meet program goals; the status of activities of the Project Office, managed by the Jet Propulsion Laboratory (JPL); and, because this is a meeting on materials, answers beings developed by the Project Office to vital questions on refractory alloy technology.

A CaO-SiO/sub 2/-H/sub 2/O macromolecular-ionomer complex was found to be formed in the superficial layers of MMA-TMPTMA copolymer composite films made with filler containing hydraulic cement during exposure in an autoclave at temperatures up to 200/sup 0/C. This superficially formed complex in terms of self-healing protective layers, acted to prevent the hydrothermal deterioration of the original composite films, which is important if the films are used as protective layers on metals. Studies of the adhesion of the complex composite coatings to chemically treated metal surfaces were also performed. It was found that the surface topography of hopeite crystalline layers results in an increase in wetting forces and mechanical interlocking forces.

The use of lasers for uranium and/or plutonium isotope separation is expected to be the first application of lasers utilizing specific atomic processes for large-scale materials processing. Specific accomplishments toward the development of production-scale technology for LIS systems will be presented, along with the status of major construction projects. 24 figures.

We report laser experiments on a 248 nm KrF laser with a 30x40x120 cm gain volume and an injection locked unstable resonator cavity. The volume is pumped by six 450 kV, 90 kA electron beam generators using water pulse forming lines.

We will soon add a high-field axisymmetric throttle region to the central cell of the TMX-U. Field amplitude will be adjusted between 2.25 and 6.0 T. This field is produced by adding a high-field solenoid and a cee coil to each end of the central cell. We describe these coils as well as the additions to the restraint structure. We analyzed the stresses within the solenoid using the STANSOL code. In addition, we performed a finite-element structural analysis of the complete magnet set with the SAP4 code. Particular attention was paid to the transition section where the new magnets were added and where the currents in the existing magnets were increased. The peak temperature rise in the throttle coil was calculated to be 41/sup 0/C above ambient.

The Mirror Fusion Test Facility (MFTF-B) control system architecture requires the Supervisory Control and Diagnostic System (SCDS) to communicate with a LSI-11 Local Control Computer (LCC) that in turn communicates via a fiber optic link to CAMAC based control hardware located near the machine. In many cases, the control hardware is very complex and requires a sizable development effort prior to being integrated into the overall MFTF-B system. One such effort was the development of the Electron Cyclotron Resonance Heating (ECRH) system. It became clear that a stand alone computer system was needed to simulate the functions of SCDS. This paper describes the hardware and software necessary to implement the SCDS Simulation Computer (SSC). It consists of a Digital Equipment Corporation (DEC) LSI-11 computer and a Winchester/Floppy disk operating under the DEC RT-11 operating system. All application software for MFTF-B is programmed in PASCAL, which allowed us to adapt procedures originally written for SCDS to the SSC. This nearly identical software interface means that software written during the equipment development will be useful to the SCDS programmers in the integration phase.

The technique of inductive stabilization of rare-gas halide discharges have been shown to yield long pulse laser outputs. The 1% efficiency obtained for the miniature short pulsed devices are believed to be very good. Length scaling to improve the gain per round trip of the laser cavity should improve the peak power in the cavity and greatly improve the extraction efficiency. This work is presently in progress. The measurement of a saturation energy for electrical energy deposition gives an important design criteria for high efficiency lasers. This number is believed to be valid regardless of the time scale of the energy deposition.

Separate abstracts were prepared for individual papers. (MHR)

Two of the French pipe whip experiments are reproduced with the computer code WIPS. The WIPS results are in good agreement with the experimental data and the French computer code TEDEL. This justifies the use of its pipe element in conjunction with its U-bar element in a simplified method of impact analyses.

A theoretical model (FASTGRASS) has been used for predicting the behavior of fission gas and volatile fission products (VFPs) in UO/sub 2/-base fuels during steady-state and transient conditions. This model represents an attempt to develop an efficient predictive capability for the full range of possible reactor operating conditions. Fission products released from the fuel are assumed to reach the fuel surface by successively diffusing (via atomic and gas-bubble mobility) from the grains to grain faces and then to the grain edges, where the fission products are released through a network of interconnected tunnels of fission-gas-induced and fabricated porosity.

One of the most exciting developments in the physics of the 20th Century is the proposal that locally gauge invariant groups describe the strong, electromagnetic and weak interactions. SU(2)/sub L/ x U(1) the electroweak group has had enormous successes including the recent discovery of the W/sup +-/ and Z/sup 0/. In the case of strong interactions, Quantum Chromodynamics is built upon the local gauge invariance of SU(3)/sub color/ which gives rise to the eight massless spin 1 gauge bosons which carry color called gluons. The colored quarks are then added to yield Quantum Chromodynamics (QCD). Although there have been many dynamical and static successes of QCD, there has been one important missing link in QCD which casts a dark shadow over it and SU(3)/sub color/. Let us assume the strong interactions are described by locally gauge invariant SU(3)/sub color/ in a pure Yang Mills theory. Then if we consider the effects of confinement one is inescapably led to the existence of glueballs (multigluon resonant states). Experimentally we found vast numbers of q anti q states and qqq states but until recently no convincing evidence for glueballs. Fortunately recent work has led to the discovery of glueballs provided one assumes the …

The Advanced Toroidal Facility (ATF) is a large torsatron being designed at Oak Ridge National Laboratory (ORNL) to replace the Impurity Study Experiment (ISX-B) tokamak. ATF will have a major radius of 2.1 m and an average plasma minor radius of 0.3 m. Major components of the device include the coil sets, structure, and vacuum vessel. The coil sets are designed for broad operating envelopes, including the capability to drive up to 100 kA of plasma current, to produce helical axis configurations, and to operate continuously at one-half the baseline currents. The ATF structure consists of a 40-mm-thick stainless steel toroidal shell encasing the helical coil set. The shell is constructed from 24 identical upper and lower segments, with 12 pairs of intermediate panels to provide access to the helical field (HF) coil joints. The lower portion of the shell also serves as an assembly fixture for the HF coil set. The vacuum vessel is a highly contoured 6-mm-thick stainless steel shell closely fitting the bore and sidewalls of the HF coil winding to provide maximum volume for the plasma. Forty-eight large ports allow good access for diagnostics and neutral beam injection.

A new Pool-Bed model of the CONACS (Containment Analysis Code System) code represents a major advance over the pool models of other containment analysis code (NABE code of France, CEDAN code of Japan and CACECO and CONTAIN codes of the United States). This new model advances pool-bed modeling because of the number of significant materials and processes which are included with appropriate rigor. This CONACS pool-bed model maintains material balances for eight chemical species (C, H/sub 2/O, Na, NaH, Na/sub 2/O, Na/sub 2/O/sub 2/, Na/sub 2/CO/sub 3/ and NaOH) that collect in the stationary liquid pool on the floor and in the desposit bed on the elevated shelf of the standard CONACS analysis cell.

Tantalum is determined by direct current plasma spectrometry after separation of plutonium from solution as PuF/sub 3/. After centrifugation of the PuF/sub 3/ precipitate, a low level of plutonium remains in solution in sufficient quantity to cause spectral interferences. It is necessary to determine the plutonium by dc plasma spectrometry and apply a correction to determine low tantalum concentrations with good accuracy and precision. Tantalum can be determined down to 0.4 ppM in solution with a relative standard deviation of 10 percent. Better precision can be achieved at higher concentrations. The procedure is simple and convenient for glovebox work. 5 references, 1 figure, 1 table.

Three points are emphasized: that the solar flare is that particular astrophysical phenomenon that is the extremum of reconnection, no other phenomenon demands as rapid magnetic flux annihilation as is seen in the solar flare; that plasma physics experiments can and should be performed in the laboratory that model reconnection as we observe it in astrophysics; and that stochastic field lines derived from something similar to Alfven wave turbulence are a necessary part of reconnection.

Current activities include development of high temperature drilling fluids, methods for plugging lost circulation zones, advanced rock cutting techniques, and borehole instrumentation. Three specific projects which are being pursued include: a method for locating fractures which do not intersect the wellbore, a laboratory for simulating lost circulation zones - to be used for development of new materials and techniques, and the understanding of the capabilities and limitations of polycrystalline diamond cutter bits in the geothermal environment.

Analysis of tracer recovery curves from injection-backflow testing at two geothermal reservoirs reveals large differences in responsebetween the two. The east Mesa reservoir is in a layered sandstone matrix, and tracer behavior can be adequately described by porous media theory. As the volume of water injected into the reservoir increases and, consequently, the depth of penetration into the formation, the ratio of dispersive flux to advective flux decreases, indicating the increasing importance of advective transport. This effect can be seen in normalized tracer recovery curves that become more symmetrical with greater injection volume. At the Raft River site, the reservoir is dominated by a single major fracture zone. Injecting larger volumes of water into the fracture does not change the shape of the normalized tracer recovery curves. This indicates that the dispersion coefficient increases proportionally to the distance traveled by the injection front. Differences in the shape of tracer recovery curves are related to fundamental differences in reservoir characteristics. Long tails on the tracer recovery curves at Raft River suggest a dual porosity reservoir with a secondary fracture network connected to the major fracture. Such findings may considerably affect calculations of secondary heat recovery using injection wells.

The Spheromak is a magnetic confinement device that is being explored in both the US and Japanese fusion programs. It is a member of the Compact Torus family of magnetic structures characterized by a set of closed, nested toroidal flux surfaces but without any coils, transformer cores, etc. protruding through the hole in the torus. The Speromak is closely elated to the Reversed Field Pinch (RFP) in that most of the magnetic field is produced by plasma currents flowing along the magnetic field lines (a near force free field) rather than by external coils. The Spheromak has magnetic field components of comparable strength in both the toroidal (azimuthal) and poloidal (in the plane perpendicular to the azimuthal unit vector) directions. The large internal magnetic energy in the Spheromak makes it rich in magnetohydrodynamic phenomena and reconnection, in particular, plays an important role in the formation, resistive decay and instability processes.

Hydrodynamic models have been derived by Mark and Yu and by others to described energetic self-pinch beams, such as those used in ion-beam fusion. The closure of the Mark-Yu model is obtained with adiabatic assumptions mathematically analogous to those of Chew, Goldberger, and Low for MHD. The other models treated here use an ideal gas closure and a closure by Newcomb based on an expansion in V/sub th//V/sub z/. Features of these hydrodynamic beam models are compared with a kinetic treatment.

The two-phase flow program is directed at understanding the hydrodynamics of two-phase flows. The two-phase flow regime is characterized by a series of flow patterns that are designated as bubble, slug, churn, and annular flow. Churn flow has received very little scientific attention. This lack of attention cannot be justified because calculations predict that the churn flow pattern will exist over a substantial portion of the two-phase flow zone in producing geothermal wells. The University of Houston is experimentally investigating the dynamics of churn flow and is measuring the holdup over the full range of flow space for which churn flow exists. These experiments are being conducted in an air/water vertical two-phase flow loop. Brown University has constructed and is operating a unique two-phase flow research facility specifically designed to address flow problems of relevance to the geothermal industry. An important feature of the facility is that it is dedicated to two-phase flow of a single substance (including evaporation and condensation) as opposed to the case of a two-component two-phase flow. This facility can be operated with horizontal or vertical test sections of constant diameter or with step changes in diameter to simulate a geothermal well profile.

Superconducting magnets for mirror fusion have evolved considerably since the Baseball II magnet in 1970. Recently, the Mirror Fusion Test Facility (MFTF-B) yin-yang has been tested to a full field of 7.7 T with radial dimensions representative of a full scale reactor. Now the emphasis has turned to the manufacture of very high field solenoids (choke coils) that are placed between the tandem mirror central cell and the yin-yang anchor-plug set. For MFTF-B the choke coil field reaches 12 T, while in future devices like the MFTF-Upgrade, Fusion Power Demonstration and Mirror Advanced Reactor Study (MARS) reactor the fields are doubled. Besides developing high fields, the magnets must be radiation hardened. Otherwise, thick neutron shields increase the magnet size to an unacceptable weight and cost. Neutron fluences in superconducting magnets must be increased by an order of magnitude or more. Insulators must withstand 10/sup 10/ to 10/sup 11/ rads, while magnet stability must be retained after the copper has been exposed to fluence above 10/sup 19/ neutrons/cm/sup 2/.

About 200 refractory metal clad ceramic fuel pins have been irradiated in thermal reactors under the 1200 K to 1550 K cladding temperature conditions of primary relevance to space reactors. This paper reviews performance with respect to fissile atom density, operating temperatures, fuel swelling, fission gas release, fuel-cladding compatibility, and consequences of failure. It was concluded that UO/sub 2/ and UN fuels show approximately equal performance potential and that UC fuel has lesser potential. W/Re alloys have performed quite well as cladding materials, and Ta, Nb, and Mo/Re alloys, in conjunction with W diffusion barriers, show good promise. Significant issues to be addressed in the future include high burnup swelling of UN, effects of UO/sub 2/-Li coolant reaction in the event of fuel pin failure, and development of an irradiation performance data base with prototypically configured fuel pins irradiated in a fast neutron flux.

Developing a definition of an engineering test reactor (ETR) is a current goal of the Office of Fusion Energy (OFE). As a baseline for the mirror ETR, the Fusion Power Demonstration (FPD) concept has been pursued at Lawrence Livermore National Laboratory (LLNL) in cooperation with Grumman Aerospace, TRW, and the Idaho National Engineering Laboratory. Envisioned as an intermediate step to fusion power applications, the FPD would achieve DT ignition in the central cell, after which blankets and power conversion would be added to produce net power. To achieve ignition, a minimum central cell length of 67.5 m is needed to supply the ion and alpha particles radial drift pumping losses in the transition region. The resulting fusion power is 360 MW. Low electron-cyclotron heating power of 12 MW, ion-cyclotron heating of 2.5 MW, and a sloshing ion beam power of 1.0 MW result in a net plasma Q of 22. A primary technological challenge is the 24-T, 45-cm bore choke coil, comprising a copper hybrid insert within a 15 to 18 T superconducting coil.