Ferritic steels have been receiving significant attention for possible use as steam generator tubing, and as alternate structural materials for liquid-metal heat-transport systems in commercial fast reactors, fusion reactors, etc. The materials are chosen on the basis of their high thermal conductivity, resistance to stress-corrosion-cracking in aqueous and steam environments, favorable fabricability and fairly low cost. These steels are available in several classes based on the microstructure and alloy content, viz., martensitics, bainitics, delta ferritics, and duplex steels. The low alloy bainitic steels (Fe-2-1/4Cr-1Mo) undergo extensive decarburization when exposed to high temperature flowing sodium. It is for this reason that ferritic steels with higher chromium (9 to 12% Cr) content have been proposed to minimize the carbon transfer and eventual degradation of mechanical properties. The martensitic steels, HT-9 and improved Fe9Cr1Mo are being considered as cladding/duct materials for liquid metal reactors (LMR). The alloy HT-9 is based on 12Cr1Mo composition. The improved Fe9Cr1Mo alloy is based on 9Cr1Mo composition as its name implies. The objective of the work reported here is to evaluate the sodium compatibility of the alloys at temperatures and flow rates typical of LMR cores. Testing was done for 8104 hours at 60/sup 0/C and 3992 hours …

The linearized drift kinetic equation is solved numerically to obtain the Onsager transport matrix for a three-dimensional toroidal plasma confinement geometry. Local transport coefficients relating the cross-field fluxes to the thermodynamic forces are computed as continuous functions of the collision frequency. In particular, in the low-collision-frequency regime (..nu.. < ..omega../sub b/), the transport resulting from the nonconservation of the longitudinal adiabatic invariant J (due to particle transitions from helically trapped to toroidally trapped) is obtained. The boundary layer in velocity space resulting from these transition particles can be accurately treated using a Legendre polynomial representation for the pitch angle dependence of the distribution function. Magnetic coordinates are used so that finite-beta effects are included. The disparity in the time scales between collisionless particle orbits and collisional dynamics is treated efficiently to obtain steady-state fluxes and viscosity coefficients. This yields significant improvements in the precision and computational effort in comparison with Monte Carlo methods. The effect of a radial electric field in the ..nu.. < ..omega../sub D/ regime is studied. Applications to Advanced Transition Facility (ATF) and heliac configurations are given.

Evaluation of the thermohydrological conditions near high-level waste packages is needed for the design of the waste canister and for overall repository design and performance assessment. Most available studies in this area have assumed that the hydrologic properties of the host rock do not change in response to the thermal, mechanical or chemical effects caused by waste emplacement. However, the ramifications of this simplifying assumption have not been substantiated. We have studied dissolution and precipitation of silica in thermally driven flow systems, including changes in formation porosity and permeability. Using numerical simulation, we compare predictions of thermohydrological conditions with and without inclusion of silica redistribution effects. Two cases were studied, namely, a canister-scale problem, a repository-wide thermal convection problem, and different pore models were employed for the permeable medium (fractures with uniform or non-uniform cross sections). We find that silica redistribution generally has insignificant effects on host rock and canister temperatures, pore pressures, or flow velocites.

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.

The Ion Beam Facility operated for 6000 machine hours last year, ranging in energy from 300 Kev to 24 Mev. Improvements include cryopumps replacing diffusion pumps, a rebuilding of the tandem chopper electronics and the vertical's corona charging system. Methane molecules were successfully accelerated by the vertical in quantities of hundreds of nanoamperes. Two replacement magnet power supplies on the tandem and a completely new capacitor shell regulator on the vertical are soon to be installed.

The Ion Cyclotron Resonant Heating (ICRH) slot antenna has been a part of the ion and electron plasma heating system in the central cell region of the Tandem Mirror Experiment-Upgrade (TMX-U). This paper presents the mechanical design and arrangement of the antenna, coax feed lines, feedthroughs, and matching network for the slot antenna.

Magnetic drift pumping on TMX-U involves driving four antennae through high Q-resonant circuits. One of the key elements in the resonant circuit is a variable inductor able to carry the 3500 amperes through the circuit and maintain its shape and inductance. The eight resonant circuits can be combined to feed the four antennae with one or two frequencies on each antenna, or frequency shift keying between two frequencies. Each resonant circuit is fed by two 10 to 30 kHz exciters capable of delivering 80 kW each to the circuit. Each exciter receives its power from its own adjustable 0 to 400 volt power supply. The entire system is controlled by a CAMAC control system over a fiber-optic link. The control system checks interlock status, controls ''On'' and ''Off'' status, calculates and adjusts phasing of the exciters for addition or deletion of the proper beat frequencies, and monitors operation. 3 refs., 5 figs.

The General Purpose Powder Diffractometer (GPPD), a high resolution ( d/d = 0.002) time-of-flight instrument, exhibits a resolution function that is almost independent of d-spacing. Some of the special properties of time-of-flight scattering data obtained at a pulsed neutron source will be discussed. A method is described that transforms wavelength dependent data, obtained at a pulsed neutron source, so that standard structural least-squares analyses can be applied. Several criteria are given to show when these techniques are useful in time-of-flight data analysis. 14 refs., 6 figs., 1 tab.

Present ion sources produce deuterium ions plus small amounts of impurity ions including oxygen. The oxygen current is readily trapped by the Mirror Fusion Test Facility-B (MFTF-B) plasma and represents a severe energy loss mechanism. A pure-beam source-neutralizer has been designed by LLNL for the MFTF-B. This concept uses momentum separation by closely coupling an electromagnet to the source to purify the beam. This design requires a low pressure in the neutralizer, implying a long length and a large diameter for high conductance. Present designs require a 55-in. diameter by 60-in. long magnetically shielded region. This shield encloses the source and the separator magnet, and acts as the neutralizer duct for the beam. The fringe fields from the MFTF-B magnets penetrate the pure-beam neutralizer along the beamline axis. Field strengths on the order of three hundred gauss must be reduced to less than 6 gauss axial and 0.2 gauss transverse to the beam. Conventional single and double layer shielding designs require excessive amounts of permeable material. Multiple layer shields using a soft iron outer shield with a highly permeable inner shield require a 4 3/4-in.-thick outer shield. We have rejected this as a possible shielding solution. Active shielding, using two …

We have installed a new diagnostic instrument to investigate ions emanating along magnetic-field lines of the TMX-U tandem-mirror experiment. This analyzer contains parallel electric and magnetic fields, which yield ion mass and energy spatial separation. A dual array of 128 copper collector plates detects particles in the ion flux that is first collimated and then focused through the 180-degree bending magnetic field. An electric field applied transverse to the bending particle path then separates the ion masses in the direction perpendicular to the magnetic-pole faces while the magnetic field spreads out the different energies of each mass in a plane parallel to the magnetic-pole tips. The CAMAC-based data recorders are fiber-optically coupled to the system controller for data acquisition, analysis, and display. A commercial CAMAC data recorder was modified for current input. We expect to measure higher particle energies than the present gridded end-loss analyzers as well as to more accurately determine the energy spectra.

The Common Long Pulse Source (CLPS) is designed to meet the differing long pulse neutral beam requirements of TFTR, Doublet III-D, and MFTF-B. The mechanical baseline design to meet these requirements is described along with supporting engineering data collected during the testing of the prototype LBL 10 x 40 Long Pulse Accelerator (LPA) and the Long Pulse Plasma Source (LPS). The CLPS is a scaled up design of the LPA and LPS and can be configured for 120 keV, 70 A D/sub 2/ non-focused, and, 80 keV, 80 A H/sub 2/ or 50 A D/sub 2/ with a 10 m focal length. The two configurations use identical major components, such as accelerator grids, supporting structures, insulators and plasma sources. Ion beam optics are analytically modeled and the results are presented along with the electric field gradients and thermal calculations for various components. A low technology plasma source back plate electron dump design has been adopted. A full scale model of CLPS was constructed, and the baseline design has been transferred to industry. 7 refs., 5 figs.

Properties of the radiation emitted by a plane sinusoidal undulator are calculated in the far field approximation. Software has been developed to calculate the spectral distribution and polarization of the radiated intensity I(E) at a point on (or integrated over) a cross sectional observation plane of the photon beam. Spatial distribution of monochromatic radiation and power density contours are also calculated. Spectral broadening caused by an electron beam of finite spatial distribution is considered. Dispersive properties of the photon beam, including the dependence on deflection parameter, are analyzed. It is shown that reasonably constant intensity distribution I(E) can be obtained by properly shaping the beam acceptance aperture. 5 refs., 11 figs.

In 1980, the US Department of Energy gave the Lawrence Livermore National Laboratory approval to design and build a tandem Mirror Fusion Test Facility (MFTF-B) to support the goals of the National Mirror Program. We designed the MFTF-B vacuum vessel both to maintain the required ultrahigh vacuum environment and to structurally support the 42 superconducting magnets plus auxiliary internal and external equipment. During our design work, we made extensive use of both simple and complex computer models to arrive at a cost-effective final configuration. As part of this work, we conducted a unique dynamic analysis to study the interaction of the 32,000-tonne concrete-shielding vault with the 2850-tonne vacuum vessel system. To maintain a vacuum of 2 x 10 Y Torr during the physics experiments inside the vessel, we designed a vacuum pumping system of enormous capacity. The vacuum vessel (4200 mT) has been fabricated, erected, and acceptance tests have been completed at the Livermore site. The rest of the machine has been assembled, and individual systems have been successfully checked. On October 1, 1985, we began a series of integrated engineering tests to verify the operation of all components as a complete system.

The principle behind the Cherenkov Ring Imaging Detectors (CRIDs) involves focussing the Cherenkov light, emitted by a relativistic charged particle in passing through a radiator medium, onto a high efficiency photocathode which can be in turn read out with good spatial resolution, to localize the point of origin of the photoelectrons. This information permits the reconstruction of the circle of Cherenkov light for each particle above threshold, and hence the determination of the Cherenkov angle to an accuracy of a few percent. The groups currently working on these detectors are discussed, the status of these projects is examined, and progress is reported on the R and D on two 4-pi devices being prepared for physics at the Z. The activities are being done at Fermilab, CERN, and SLAC. 8 refs., 32 figs. (LEW)

The appropriate approach to risk or hazard assessment can vary considerably, depending on various factors, including the intended application of the results and the time other resources available to conduct the assessment. This paper illustrates three types of interrelated assessments. Although they can be mutually supportive, they have fundamentally different objectives, which require major differences in approach. The example of the overall risk assessment of alternative major energy technologies illustrates the compilation of a wide range of available risk data applicable to these systems. However, major uncertainties exist in the assessments, and public perception of their importance could play an important role in final system evaluations. A more narrowly defined risk assessment, often focusing on an individual component of a larger system, is the most commonly used approach in regulatory applications. The narrow scope allows in-depth analysis of risks and associated uncertainties, but it may also contribute to a loss of perspective on the magnitude of the assessed risk relative to that of the unassessed risks. In some applications, it is useful to conduct semiquantitative degree-of-hazard evaluations as a means of setting priorities for detailed risk assessment. The MAHAS procedure described in this paper provides a means of rapidly ranking …

The motivation for creating a permanent lunar settlement is sketched, and reasons for doing so in the coming decade are put forward. A basic plan to accomplish this is outlined, along technical and programmatic axes. It is concluded that founding a lunar settlement on the five hundredth anniversary of the Columbus landing - a Columbus Project - could be executed as a volunteer-intensive American enterprise requiring roughly six thousand man-years of skilled endeavor and a total Governmental contribution of the order of a half-billion dollars. 8 figs.

Since its construction and commissioning was completed in the winter of 1981, the Tandem Mirror Experiment Upgrade (TMX-U) has been conducting tandem mirror thermal barrier experiments. The work, following the fall of 1983 when strong plugging with thermal barriers was achieved, has been directed toward controlling radial transport and forming thermal barriers with high density and Beta. This paper describes the overall engineering component of these efforts. Major changes to the machine have included vacuum improvements, changes to the Electron and Ion Cyclotron Resonance Heating systems (ECRH and ICRH), and the installation of a Plasma Potential Control system (PPC) for radial transport reduction. TMX-U operates an extensive diagnostics system that acquires data from 21 types of diagnostic instruments with more than 600 channels, in addition to 246 machine parameters. The changes and additions will be presented. The closing section of this paper will describe the initial study work for a proposed TMX-U octupole configured machine.

This report presents information on rf system design for the compact ignition tokamak. Topics discussed in this report include: frequency choice; plasma coupling analysis; launcher design; ORNL resonant double loop antenna; ORNL ''folded'' waveguide; recessed antennas; ICRH launcher R and D; and Faraday shield R and D. (JDB)

The design of a negative ion beam transport system is discussed. The ion source and accelerator have produced a 1-A, 8 keV beam of H ions with a pulse length of 30 seconds. The beam was additionally characterized as to electron content, uniformity along the slot, emittance perpendicular to the slot, and the beam divergence. 8 refs., 5 figs. (WRF)

The process by which the radiation intensity grows and correlation in the electron distribution develops, as the beam passes through a long undulator, is described.

In situ high-voltage electron microscope (HVEM) studies have shown that the highly focused electron beams normally employed for irradiation purposes in the HVEM can cause easily measurable composition changes in the irradiated volume of thin alloy films (Ni-Al). The kinetics of this ''beam-induced'' composition change has been investigated and found to exhibit a strong dependence not only on temperature and peak electron flux, but also on the beam diameter. The dependence on beam diameter has far reaching implications for HVEM studies of radiation effects in alloys, and for microchemical analysis techniques such as EDX and EELS.

Low-energy ions trapped in the thermal barrier region of the TMX-U plasma cause a potential reduction which results in increased scattering and less thermal isolation between regions of the plasma. A method of removing these ions using magnetic field perturbations at the ion drift frequency has been developed. The concepts of ''drift pumping'' and hardware development are described in this paper. 5 refs., 7 figs.

The Division of Development and Technology has sponsored a four day US-Japan workshop ''Plasma-Wall Interaction Data Needs Critical to a Burning Core Experiment (BCX)'', held at Sandia National Laboratories, Livermore, California on June 24 to 27, 1985. The workshop, which brought together fifty scientists and engineers from the United States, Japan, Germany, and Canada, considered the plasma-material interaction and high heat flux (PMI/HHF) issues for the next generation of magnetic fusion energy devices, the Burning Core Experiment (BCX). Materials options were ranked, and a strategy for future PMI/HHF research was formulated. The foundation for international collaboration and coordination of this research was also established. This volume contains the last three of the five technical sessions. The first of the three is on plasma materials interaction issues, the second is on research facilities and the third is from smaller working group meetings on graphite, beryllium, advanced materials and future collaborations.

A description of atomic physics experiments that we intend to carry out at the National Synchrotron Light Source is given. Emphasis is given to work that investigates the properties of multiply charged ions. The use of a synchrotron storage ring for highly charged heavy ions is proposed as a way to produce high current beams which will make possible experiments to study the photoexcitation and ionization of multiply charged ions for the first time. Experiments along the same lines which are feasible at the proposed Advanced Light Source are considered briefly. 7 refs., 2 figs.