The Zircaloy cladding of water reactor fuel rods is susceptible to local breach-type failure, commonly known as pellet-cladding interaction (PCI) failure, during operational and off-normal power transients after the fuel has achieved a sufficiently high burnup. An optimization of power ramp procedures or fuel rod fabrication to minimize the cladding failure would result in a significant decrease in radiation exposure of plant personnel due to background and airborne radioactivity as well as an extension of core life in terms of allowable off-gas radioactivity. As part of a program to provide a better understanding of the fuel rod faiure phenomenon and to facilitate the formulation of a better failure criterion, a mechanistic study of the deformation and fracture behavior of high-burnup spent-fuel cladding is in progress under simulated PCI conditions.

A new generation of neutron sources is just coming into existence with great promise for the future. These sources are based on neutron production by spallation from the interaction of high energy protons with a heavy metal target. Currently the highest flux facility of this type is the Intense Pulsed Neutron Source at Argonne National Laboratory. This machine is also unique in its dedication to both slow-neutron scattering and fast-neutron damage studies.

PCI-like, brittle-type failures, characterized by pseudocleavage-plus-fluting features in the fracture surface, branching cracks, and small diametral strain, were observed to occur at 292 to 325/sup 0/C in some batches of spent power-reactor fuel-cladding tubes under internal gas-pressurization and expanding-mandrel loading conditions in which the tests were not influenced by fission product simulants. Fractographic characteristics per se do not provide evidence for a PCI failure mechanism but should be deemed only as cooroborative in nature. Evaluation of TEM thin-foil specimens, obtained from regions adjacent to the brittle-type fracture sites, characteristically revealed extensive amounts of Zr/sub 3/O precipitates and a lack of slip dislocations. The precipitation of the Zr/sub 3/O phase appears to be enhanced by a high density of irradiation-induced defects. The brittle-type failure produced in the spent-fuel cladding tubes appears to be associated with segregation of oxygen to dislocation substructures and irradiation-induced defects, which leads to the formation of an ordered zirconium-oxygen phase of Zr/sub 3/O, an immobilization of dislocations, and minimal plastic deformation in the cladding material.

A preliminary investigation of the feasibility of acoustic imaging of vapor bubbles through optically nontransparent media is described. Measurements are reported showing the echo signals produced by air filled glass spheres of various sizes positioned in an aqueous medium as well as signals produced by actual vapor bubbles within a water filled steel pipe. In addition, the influence of the metallic wall thickness and material on the amplitude of the echo signals is investigated. Finally several examples are given of the imaging of spherical bubbles within metallic pipes using a simulated array of acoustic transducers mounted circumferentially around the pipe. The measurement procedures and a description of the measuring system are also given.

The writer objects to the consensus that doubled CO/sub 2/ levels will lead to a global temperature increase of 3/sup 0/C and the associated implications for mankind. In this paper he presents his reasons for doubting the majority view on two climatic feedback processes: (1) the ice-albedo feedback, and (2) the water vapor feedback. (ACR)

Some properties of chiral anomalies are described from a geometric point of view. Topics include chiral anomalies and differential forms, transformation properties of the anomalies, identification and use of the anomalies, and normalization of the anomalies. 22 references. (WHK)

The theoretical FASTGRASS model for the prediction of the behavior of the gaseous and volatile fission products in nuclear fuels under normal and transient conditions has undergone substantial improvements. The major improvements have been in the atomistic and bubble diffusive flow models, in the models for the behavior of gas bubbles on grain surfaces, and in the models for the behavior of the volatile fission products iodine and cesium. The thoery has received extensive verification over a wide range of fuel operating conditions, and can be regarded as a state-of-the-art model based on our current level of understanding of fission product behavior. PARAGRASS is an extremely efficient, mechanistic computer code with the capability of modeling steady-state and transient fission-product behavior. The models in PARAGRASS are based on the more detailed ones in FASTGRASS. PARAGRASS updates for the FRAPCON (PNL), FRAP-T (INEL), and SCDAP (INEL) codes have recently been completed and implemented. Results from an extensive FASTGRASS verification are presented and discussed for steady-state and transient conditions. In addition, FASTGRASS predictions for fission product release rate constants are compared with those in NUREG-0772. 21 references, 13 figures.

Male germ cells respond dramatically to a variety of insults and are important reproductive dosimeters. Semen analyses are very useful in studies on the effects of drugs, chemicals, and environmental hazards on testicular function, male fertility and heritable germinal mutations. Sperm were analyzed by flow cytometry and slit-scan flow analysis for injury following the exposure of testes to mutagens. The utility of flow cytometry in genotoxin screening and monitoring of occupational exposure was evaluated. The technique proved valuable in separation of X- and Y-chromosome bearing sperm and the potential applicability of this technique in artificial insemination and a solution, of accurately assessing the DNA content of sperm were evaluated-with reference to determination of X- and Y-chromosome bearing sperm.

A general overview of the nucleosynthesis mechanisms for heavy (A greater than or equal to 70) nuclei is presented with particular emphasis on critical data needs. The current state of the art in nucleosynthesis models is described and areas in which fission product data may provide useful insight are proposed. 33 references, 10 figures.

Greater than 99% of all incoming Po-210 reports to the tailing piles for both the acid and the alkaline leach uranium circuits. Leached Po-210 may be carried along on small particles rather than dissolved in solution. There does not appear to be any radiologically significant buildup or accumulation in the acid leach circuit, but there are noteworthy amounts in the molybdenum recovery solution.

Possibilities for characterizing the thermal properties of fast paths by means of different types of tests (tracers, pressure transients, non-isothermal injection) are discussed. Thermal breakthrough in vertical fractures is examined in some detail, using an idealized model for which an analytical solution is available. The model shows that rapid tracer returns are not necessarily indicative of rapid thermal interference. Thermal breakthrough predictions can be made from tracer data only, if both fluid residence time and tracer dispersion are taken into account. However, due to the geometric simplifications necessary in analyzing the tracer data, thermal interference estimates on this basis appear questionable. Pressure transient tests can provide additional parameters for thermal interference predictions, but they cannot resolve the problem of non-uniqueness. A more reliable determination of thermal characteristics of fast paths appears possible from non-isothermal injection tests, combined with numerical simulation. A mixed numerical/semi-analytical approach is employed to model the three-dimensional fluid and heat flow in injection-production systems in vertical fractures, with heat transfer to and from the adjacent rock matrix. Illustrative calculations of thermal recovery after different injection periods suggest that shutting-in an injection well can prevent unacceptable temperature declines at production wells.

Lead glass counters made of wedge shaped blocks of SF6 were tested with positrons at SLAC. The beam energy ranged from 2 to 17.5 GeV. Energy dependence and beam position dependence of pulse height and energy resolution were studied with lead glass blocks of various lengths. The effect of a BK-7 light guide on pulse height was clearly observed. Degradation of the energy resolution due to aluminum absorbers of various lengths was investigated. A mesh type photomultiplier was also tested.

The development of a geothermal resource for energy is often seriously hindered by conflict with the alternative use of the same geothermal resource for recreation. Incompatibility between the development of geothermal energy and the enjoyment of surficial thermal features has constrained development in Japan, New Zealand, Europe, and the United States. Four approaches to the resolution of this problem have been identified. They are (1) research, (2) new technology, (3) design, and (4) marketing.

The immediate effects of a full-scale nuclear war would be large and severe. The survivors of such a war would have to endure possible changes in the chemical structure of the atmosphere. These changes may come about as a result of changes caused by the nuclear explosions themselves (direct effects) or as a result of changes caused by fires that may start after the explosions (indirect effects). This paper focuses on the expected global-scale changes in the chemical structure of the atmosphere from both direct and indirect effects after a full-scale nuclear exchange. The immediate effects of a nuclear explosion include the creation of a hot mass of air or fireball which rises in the atmosphere to a level that depends on the yield of the explosion. Because the fireball is hot, it is able to dissociate atmospheric nitrogen, N/sub 2/. As the fireball cools, nitrogen atoms recombine with oxygen to form nitrogen oxides, NO and NO/sub 2/. In addition, dust and recondensed gases are swept up through the stem of the fireball and deposited at the same level to which the fireball rises. This paper focuses on the response of atmospheric ozone to a nuclear war.

Formation of energetic beams of negative ions of elements with atomic numbers 2 to 17 (helium to chlorine) by charge transfer in metal vapors is discussed.

The IEEE P896 Future Backplane Bus project has been influenced by and has influenced FASTBUS and several other contemporary bus designs. This paper summarizes the current status of that project, which is directed toward the needs of modern 32-bit microprocessor systems with multiple processors. Some of the technology developed for P896 will be important for future non-ECL implementations of FASTBUS and other buses. In particular, new bus drivers and receivers should greatly improve the performance and reliability of backplane buses and cable buses. The current status of the P896 serial bus is also summarized.

Separate abstracts were prepared for 24 of the included papers. (MOW)

Fiber optic technology, motivated by communications and defense applications, has advanced significantly the past ten years. In particular, advances have been made in visible radiation transmission efficiency with concurrent reductions in fiber size, weight, and cost. Researchers at the Lawrence Livermore National Laboratory (LLNL) coupled these advances in fiber optic technology with analytical fluorescence analysis to establish a new technology - remote fiber fluorimetry (RFF). Laser-based RFF offers the potential to measure and monitor from one central and remote laboratory, on-line, and in near real time, trace (ppM) to substantial (g/L) concentrations of selected chemical species in typical process, product, and waste streams. The fluorimeter consists of a fluorescence or Raman spectrometer; unique coupling optics that separates input excitation (laser) radiation from return (fluorescence) radiation; a fiber optic cable; and an optrode - a terminal that interfaces the fiber to the measurement point, which is designed to respond quantitatively to a particular chemical species. At LLNL, research is underway into optrodes that measure pressure, temperature, and pH and those that detect and quantify various actinides, sulfates, inorganic chloride, hydrogen sulfide, aldehydes, and alcohols.

The appreciation of the role in nuclear physics of the first excited state of the nucleon, the delta ..delta..(1232), has grown rapidly in the past decade. The delta resonance dominates nuclear reactions induced by intermediate energy pions, nucleons, and electromagnetic probes. It is also the most important non-nucleonic degree of freedom needed to resolve many fundamental problems encountered in the study of low-energy nuclear phenomena. Clearly, a new phase of nuclear physics has emerged and conventional thinking must be extended to account for this new dimension of nuclear dynamics. The most challenging problem we are facing is how a unified theory can be developed to describe ..delta..-nucleus dynamics at all energies. In exploring this new direction, it is important to have direct discussions among researchers with different viewpoints. Separate entries were prepared for the 49 papers presented. (WHK)

The simplest quadrilateral element available for the incompressible Navier-Stokes equations is the mixed interpolation 4-node element with bilinear velocity and (piecewise) constant pressure - denoted herein by 4/1. The next simplest is the 4/4 element, in which (continuous) bilinear approximation is also employed for pressure - i.e., the simplest case of equal-order interpolation. The 4/4 element had been more or less rejected early-on, following the pioneering work of Hood and Taylor who first discovered that equal-order interpolation generated spurious pressures. The 4/1 element, on the other hand, has been very popular, even though it sometimes generates one spurious pressure mode (vs many for the 4/4 element) which is usually filterable. But the 4/1 element generates a poor approximation to (Del P) when distorted elements are employed (via the bilinear isoparametric technique), which often leads to large errors in velocity; e.g. this element generated wrong answers for vortex shedding on the same mesh for which a higher order element (9/4) performed well. Although the 4/4 element generates ostensibly useless pressures, the pressure gradient and the velocity field might be much more accurate than those from the 4/1 element, especially when distorted meshes are employed. Based on these observations, we have successfully …

The Automation Technology Branch of NASA Langley Research Center is developing a research capability in the field of artificial intelligence, particularly as applicable in teleoperator/robotics development for remote space operations. As a testbed for experimentation in these areas, a system concept has been developed and is being implemented. This system, termed DAISIE (Distributed Artificially Intelligent System for Interacting with the Environment), interfaces the key processes of perception, reasoning, and manipulation by linking hardware sensors and manipulators to a modular artificial intelligence (AI) software system in a hierarchical control structure. Verification experiments have been performed: one experiment used a blocksworld database and planner embedded in the DAISIE system to intelligently manipulate a simple physical environment; the other experiment implemented a joint-space collision avoidance algorithm. Continued system development is planned.

Elastic and inelastic neutron scattering studies were performed on the amorphous alloy (Fe/sub 77/Cr/sub 23/)/sub 75/P/sub 16/B/sub 6/Al/sub 3/. These measurements were conducted over a temperature range from 1.8 K to room temperature. The elastic scattering results obtained at Q = 0.025A/sup -1/ indicated a Curie temperature of 185/sup 0/K in addition to a ferromagnetic-spin glass transition below 20 K. These values are consistent with the phase diagram construction resulting from the magnetization and ac susceptibility measurements of Yeshurun et al. Inelastic neutron scattering measurements resulted in well-defined spin waves being observed in the ferromagnetic phase. For the small Q range studied (0.05A/sup -1/ to 0.1A/sup -1/), the spin wave energies followed a quadratic dispersion. As the temperature was lowered towards the spin glass regime, the spin wave energies decreased indicating a softening of the magnetic stiffness constant. Below 10/sup 0/K, no well-defined spin wave excitations were present; however, a quasielastic peak, which increased slightly as the temperature was lowered, was observed.

To encourage the development of hydrothermal energy, twenty-three demonstration projects were funded. The Haakon School project is one of twelve such projects. The geothermal direct-use heating system at the Haakon School complex in Philip, South Dakota is described and information gained during approximately three heating seasons of operation is presented.

Earlier investigations of the atmospheric effects of a nuclear war focused primarily on the potential reduction in stratospheric ozone. The numerical models used in those assessments were one-dimensional and calculated the average ozone reduction over the Northern Hemisphere. The results presented here are the first assessment of the potential reduction in total ozone on a subcontinental scale. The purpose is to determine whether regions of large ozone reduction (sometimes called ozone holes) are possible, and to identify the important parameters affecting the magnitude of the ozone reduction and rate of recovery.