The structural design of the large HTGR prismatic core fuel elements involve the interaction of four engineering disciplines: nuclear physics, thermo-hydraulics, structural and material science. Fuel element stress analysis techniques and the development of structural criteria are discussed in the context of an overview of the entire design process. The core of the proposed 2240 MW(t) HTGR is described as an example where the design process was used. Probabalistic stress analysis techniques coupled with probabalistic risk analysis (PRA) to develop structural criteria to account for uncertainty are described. The PRA provides a means for ensuring that the proposed structural criteria are consistent with plant investment and safety risk goals. The evaluation of cracked fuel elements removed from the Fort St. Vrain reactor in the USA is discussed in the context of stress analysis uncertainty and structural criteria development.

Some elementary facts about holomorphic line bundles are discussed along with some applications to string theory.

Evidence is shown for the observation of five-closely spaced states in /sup 118/Cd with a centroid at 1989 keV which may represent the first identification of all five members of the three-phonon quintuplet. 11 refs., 2 figs.

The vaporization of a spherically symmetric liquid droplet homogeneously heated by a high-intensity laser pulse is investigated on the basis of a hydrodynamic description of the system composed of the vapor and ambient gas. In the limit of convective vaporization, the boundary conditions at the fluid-gas interface are formulated by using the notion of a Knudsen layer across which translational equilibrium is established. Numerical solutions to the hydrodynamic equations exhibit the existence of two shock waves propagating in opposite directions with respect to the contact discontinuity that separates the ambient gas and vapor. 17 refs., 6 figs.

Data from e/sup +/e/sup -/ collisions collected by the MAC detector at the SLAC storage ring PEP with a new vertex chamber having position resolution of 50 ..mu..m have been analyzed with a new method to make a determination of the lifetime of hadrons containing b-quarks. In addition, data collected with MAC before the vertex chamber was installed have been re-analyzed using the new method. The combined result for the B lifetime is tau/sub b/ = (1.16 +- 0.16(stat.) +- 0.07(syst.)ps) x (1 +- 0.15), where the last factor is the scale. 12 refs., 2 figs.

Quantitative analyses of angular distributions and angle-mass correlations have been applied to the U + Ca reaction to obtain upper limit estimates for the cross sections for complete fusion near or below the interaction barrier. Extrapolating to the systems Ca + Cm and Ca + Es using the well established scaling properties of the extra push model, an estimate of the cross sections relevant to the efforts of synthesizing super-heavy elements in the region Z = 116 and N = 184 via heavy-ion fusion reactions are obtained. A simple evaporation calculation using properties of the super heavy elements shows that the failure to observe super-heavy elements with the Ca + Cm reaction is consistent with estimates of the complete fusion process. 33 refs., 9 figs., 1 tab.

The surface magneto-optic Kerr effect (SMOKE) is used to explore the magnetism of ultra-thin Fe Films extending into the monolayer regime. Both bcc ..cap alpha..-Fe and fcc ..gamma..-Fe single-crystalline, multilayer films are prepared on the bulk-terminated (1 x 1) structures of Au(100) and Cu(100), respectively. The characterizations of epitaxy and growth mode are performed using low energy electron diffraction and Auger electron spectroscopy. Monolayer-range Fe/Au(100) is ferromagnetic with a lower Curie temperature than bulk ..cap alpha..-Fe. The controversial ..gamma..-Fe/Cu(100) system exhibits a striking, metastable, surface magnetic phase at temperatures above room temperature, but does not exhibit bulk ferromagnetism.

We study the use of such compounds in the strong, permanent magnet multipoles required for handling high energy, charged particle beams. We have made a number of SmCo/sub 5/ multipoles which have been used in a variety of ways, e.g., sextupoles for chromatic correction of the SLAC damping rings and quadrupoles for matching their associated injection and extraction lines. For applications in high radiation areas, we have used VACOMAX 170 thermally stabilized at 80/sup 0/C. Because our fabrication method uses measured characteristics of individual blocks in isolation, linearity over the operating range of the B-H curve is important. Stronger PM materials or multipole magnets increase the operating range which decreases linearity and increases unwanted harmonics. To study such effects, multipole magnets of VACODYM 370 are being made at different radii to emphasize high field effects which can drive parts of a magnet well into the third quadrant of the B-H curve. The results are compared to calculations based on various assumptions and our previous results for SmCo.

A new central drift chamber has been constructed for the Mark II detector for use at the new SLAC Linear Collider (SLC). The design of the chamber is based on a multi-sense-wire cell of the jet chamber type. In addition to drift-time measurements, pulse-height measurements from the sense wires provide electron-hadron separation by dE/dx. The chamber has been tested in operation at PEP before its move to the SLC. The design and construction are described, and measurements from the new chamber are presented.

A review is presented of data and theoretical interpretations of the nuclear dependence of quark and antiquark distributions as observed in the deep inelastic scattering of neutrinos and charged leptons from nuclei. After a summary of the experimental situation and a survey of proposed explanations, the author concentrates on interpretations in terms of conventional nuclear physics and on the Q/sup 2/-rescaling approach. The review concludes with a list of desirable future experiments. 32 refs., 5 figs.

A review is given on the phenomenology of CP violation in B and D decays that has been developed over the last few years. Since a firm data base on B decays is still lacking, semiquantitative scenarios are drawn. Within the Standard Model one predicts asymmetries that can be as large as O (10%) with a confidence level that ranges between hopeful and considerable. Even so, millions of produced B and D mesons are required to make such studies feasible. A B factory would be crucial in such an endeavor. 10 refs.

As heavy ion reaction studies have progressed from beam energies below 10 MeV/nucleon to higher energies, many non-equilibrium reaction phenomena have been observed. Among these are nucleon emission with velocities in excess of the beam velocity, incomplete momentum transfer to evaporation residue and fission-like fragments, ..gamma..-rays with energies in excess of 100 MeV, and ..pi../sup 0/ production when beam energies are below the threshold for production by the nucleon-nucleon collision mechanism. Additionally, prefission neutrons have been observed in excess of numbers expected from equilibrium models. A few of the approaches which have been applied to these phenomena are as follows: Intranuclear cascade: two body collisions are assumed to mediate the equilibration. The geometry and momentum space is followed semiclassically. The approach has many successes though it may suffer in a few applications is not following holes; TDHF considers one body processes only; in the energy regime of interest, two body processes are important so that this may not be a viable approach; Boltzmann-Uehling-Uhlenbeck or Vlasov-Uehling-Uhlenbeck (BUU/VUU) equations combine both one body and two body dynamics. The spatial and momentum evolution of the reactions are followed in a mean field. These should be the Cadillacs of the models. They are computationally …

Precompound decay models generally rely on use of a partial state density (PSD) formula which is generated using an assumed equidistantly spaced set of single particle levels. This is a reasonable assumption for mid-shell nuclei; however it has been demonstrated that quite large errors may be introduced by making the equidistant spacing assumption for nuclei which have neutron or proton numbers near or at major shell closures. This work reviews the simple qualitative considerations of those deviations expected for near closed shell nuclei, these expectations are compared with experimental results, and steps are taken to implement use of partial state densities calculated with more realistic sets of single particle levels in precompound decay calculations. This is done for the case of Zr targets. 13 refs., 14 figs.

Based on BNL's study it was concluded that there are low-level radioactive wastes (LLWs) which contain chemically hazardous components. Scintillation liquids may be considered an EPA listed hazardous waste and are, therefore, potential mixed wastes. Since November 1985, no operating LLW disposal site will accept these wastes for disposal. Unless such wastes contain de minimis quantities of radionuclides, they cannot be disposed of at an EPA permitted site. Currently generators of liquid scintillation wastes can ship de minimis wastes to be burned at commercial facilities. Oil wastes may also eventually be an EPA listed waste and thus will have to be considered a potential radioactive mixed waste unless NRC establishes de minimis levels of radionuclides below which oils can be managed as hazardous wastes. Regarding wastes containing lead metal there is some question as to the extent of the hazard posed by lead disposed in a LLW burial trench. Chromium-containing wastes would have to be tested to determine whether they are potential mixed wastes. There may be other wastes that are mixed wastes; the responsibility for determining this rests with the waste generator. While management options for handling potential mixed wastes are available, there is limited regulatory guidance for generators. …

Important topics concerning Muon Catalyzed Fusion were investigated in experiments at the Swiss Institute for Nuclear Research (SIN), including transient and steady state rates for the main d..mu..t cycle as well as detailed information about the competing d..mu..d and t..mu..t fusion branches. The basic kinetic parameters were determined and striking features of the resonant d..mu..t formation process were revealed (density effect, epithermal behavior). DT sticking was measured with independent techniques, i.e., detection of fusion neutrons as well as ..mu..He x-rays after fusion. Fusion yields per muon of 113 +- 10 were observed at liquid conditions, yields exceeding 200 are anticipated for optimal conditions from our results. 43 refs., 8 figs., 3 tabs.

For very heavy quark masses, the inclusive hadronic production of hadron pairs containing heavy quarks is predicted to be governed by QCD fusion subprocesses. For intermediate mass scales other QCD mechanisms can be important including higher-twist intrinsic contributions and low relative velocity enchancements, possibly accounting for the anomalies observed in charm hadroproduction, such as the nuclear number dependence, the longitudinal momentum distributions, and beam flavor dependence. We also discuss scaling laws for exclusive processes involving heavy quarks and diffractive excitation into heavy quark systems.

The performance of the Intense Pulsed Neutron Source (IPNS) Accelerator System is reported, including an increase in average beam current to 13.4 microamperes and increased reliability to 93.2%. Brief discussions are given for the performance of the major accelerator subsystems, including the H/sup -/ ion source and preaccelerator, the 50 MeV linac, and the synchrotron and its subsystems. (LEW)

Langmuir probe radial scans were achieved for several types of neutral-beam-heated 0.8 MA discharges in TFTR. The I(V) characteristics were analyzed to derive N/sub e/ and T/sub e/ profiles and extrapolated to infer the global particle confinement time tau/sub p/(t). A one-dimensional edge model was used to infer transport coefficients before and during neutral beam injection. The model indicates that ionization in the scrape-off increases the ion flux to the limiter by a factor approx.2 and alters the profiles.

Traditional methods of magnet construction (wet winding) use molded coil subassemblies bonded together with epoxy impregnated fiberglass tape. This is a highly labor intensive process involving redundant operations for each of the four coils. The epoxy free winding technique (dry winding) eliminates the epoxy curing steps and also allows all four coils to be wound on 3 common winding mandrel, thereby reducing winding stations and handling. The tooling required for dry winding is a radical departure from existing technology imposing new mechanical problems. A number of 64 cm long 5 cm aperture SSC Design B'' magnets have been produced at Fermilab utilizing dry winding techniques. Discussed is the specialized tooling created to accomplish dry winding as well as new winding and assembly procedures required. Also discussed are mechanical problems encountered and their solutions. Based on experience gained, dry winding can be a viable lower cost alternative to traditional coil fabrication techniques.

Magnetization of superconducting material can be introduced into POISSON through a field dependent permeability table (in the same way that iron characteristics are introduced). This can be done by representing measured magnetization data of the increasing and decreasing field by two independent B-..gamma.. curves (..gamma.. = 1/..mu..). Magnetization curves of this type were incorporated into the current regions of the program POISSON and their effect on the field coefficients observed. We have used this technique to calculate the effect of magnetization on the multipole coefficients of a SSC superconducting dipole magnet and to compare these coefficients with measured values.

The SSC requires a very uniform dipole field. A 40 mm bore diameter winding cross section has been developed which has computed multipole coefficients less than 1 x 10/sup -6/ of the dipole field at 10 mm radius for an operating field of 6.6T at 4.35 K. This cross section has 4 conductor blocks (3 wedges, 16 turns) per quadrant in the inner layer, and two blocks (1 wedge, 20 turns) in the outer layer. ''Partially keystoned'' cable is used; the inner cable has 23 strands of .0318 inch diameter wire; the outer cable has 30 strands of .0255 inch diameter wire. Model magnets have been constructed and the fields measured at room temperature and at liquid helium temperature up to fields exceeding 6.6T. Measured fields are compared to the predicted field. In addition, the as-built conductor positions in several magnets have been determined after cutting up the magnets. The predictions based on as-built configurations are computed and compared to measurements.

Final acceptance tests of the Mirror Fusion Test Facility (MFTF-B) were completed in February 1986. These tests verified performance of the following subsystems: the magnet system, the vacuum system and vessel, cryogenic systems, 80-keV neutral-beam sources and power supplies, microwave power systems for plasma heating, the supervisory control and diagnostic system, and the local control and instrumentation system. The entire magnet system was operated at full field continuously for 24 hours. The largest field alignment error under full load, determined using an electron beam technique, was 6 mm, well within the required precision of 15 mm. Absolute values of the magnetic field were determined using nuclear magnetic resonance techniques and were found to be within 2% of predicted values. All magnetic protection systems and fault protection systems were tested at full load. At 4.35 K, the cooling capacity of the liquid helium system exceeded the 11 kW rating and the nitrogen reliquifier met its 500 kW rating.

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 enriched uranium. Resonance photoionization is the heart of the AVLIS process. We discuss those fundamental atomic parameters that are necessary for describing isotope-selective resonant multistep photoionization along with the measurement techniques that we use. We illustrate the methodology adopted with examples of other elements that are under study in our program.

Advanced plasma fueling systems for magnetic confinement devices are being developed at the Oak Ridge National Laboratory (ORNL). The general approach is that of producing and accelerating frozen hydrogenic pellets at speeds in the range of 1-2 km/s and higher. Two specific concepts are under development: (1) high-speed pneumatic acceleration; and (2) mechanical (centrifugal) acceleration. Both approaches are being pursued to meet the projected pellet size and delivery rates for major near-term plasma confinement devices, such as the Tokamak Fusion Test Reactor (TFTR), Tore Supra, the Joint European Torus (JET), JT-60, and Doublet III-D (DIII-D), as well as future applications. In addition to these confinement physics related activities, ORNL is pursuing advanced technologies to achieve pellet velocities significantly in excess of the 2-km/s range already attained with pneumatic injectors and has embarked on a development program designed to explore the feasibility of fabricating and accelerating tritium pellets. This paper describes these ongoing activities.