The testing of the properties of packed-particle beds and regenerators at cryogenic temperatures as low as 4 K is an essential part of the magnetic refrigeration research and development program at the Los Alamos National Laboratory. We envision magnetic refrigeration and heat pump systems operating in various ranges from 4 K to ambient temperature and above. Only pressurized helium gas appears suitable as the heat exchange fluid for the low-temperature applications. Because published data on the properties of porous beds at low temperatures is sparse, we have found it necessary to develop an experimental test apparatus to study the properties of various configurations of beds and regenerators. Two of the well-known methods for such studies are the steady-enthalpy-flux method and the single-blow transient method. We have developed an experimental system in which gas flow can be suddenly switched to an alternate better (or colder) flow in step-function fashion at temperatures from 4 to 300 K. This apparatus will yield information on steady-state heat transfer and friction factors as well as on the transient behavior. Such information is very important to the design of high-efficiency magnetic refrigeration systems. This paper describes this experimental apparatus and presents the results and analysis of …

Magnetic refrigeration is a new technology that potentially offers refrigeration efficiencies > 50% of Carnot, compactness, and high reliability. Studies indicate that approx. 35% of Carnot efficiency is generally the best that is now possible for gas compression/expansion systems and, at that, only for very large plants; for smaller machines, the fraction of Carnot efficiency can become very small, e.g., 1-W refrigerators generally operate at 2 to 8% of Carnot efficiency. For magnetic refrigerators, the compression/expansion processes are replaced by a cycle involving the application/removal of a magnetic field to either a paramagnetic or ferromagnetic material (generally, paramagnets are used below approx. 20K and ferromagnets above). The thermodynamic cycles in gas and magnetic systems are analogous. Central to the development of magnetic refrigerators is the characterization of magnetic working substances. Among the key properties for which we require data are the heat capacity (from which we derive the entropy) and the thermal conductivity as functions of temperature and magnetic field. Accordingly, at the Los Alamos National Laboratory, we have designed and constructed an apparatus to make measurements of these quantities over the range 1 to 300 K at fields up to 9 T. We describe the methodology of these measurements, …

A criterion for cladding failure based on accumulated strain was developed for mixed uranium-plutonium oxide fuel pins and used to interpret the calculated strain results from failed transient fuel pin experiments conducted in the Transient Reactor Test (TREAT) facility. The new STRAIN criterion replaced a stress-based criterion that depends on the DORN parameter and that incorrectly predicted fuel pin failure for transient tested fuel pins. This paper describes the STRAIN criterion and compares its prediction with those of the stress-based criterion.

Design considerations and experimental results are presented of a compressed magnetic field pulsed energy source. A 100-mm-diameter, gun-fired projectile of approx. 2MJ kinetic energy was the input energy source. An initial magnetic field was trapped and compressed by the projectile. With a shorted load, a magajoule in a nanohenry was the design goal, i.e., 50 percent energy transformation from kinetic to magnetic. Five percent conversion was the highest recorded before gauge failure.

We develop a simple model of a beam transported in a hard wall channel (an idealized very-high-order magnetic-multipole channel). The extremely anharmonic nature of the potential leads to damping of coherent transverse displacements of the beam via phase mixing. For the case of small uniform displacements of the beam we can write down by inspection the analytical form of the motion of the beam centroid. The same technique allows us to evaluate the effects of focussing and scattering elements in the transport channel upon the damping of the transverse motion of the beam.

The turbulent dispersion of tracers nocturnal in four valleys was examined. Two are reasonably large with greater than 600-m terrain relief and two are well-formed but are shallow and narrow. Both Anderson Creek, California and Parachute Creek, Colorado are large and deep enough to produce a systematic cool air drainage wind regime although the difference in valley shapes makes the structure of that wind field quite different. Parachute Creek is a deep linear valley in which a vigorous down-valley flow develops and exits at the mouth without significant obstruction. Anderson Creek is a three-dimensional bowl with a very flat outflow region from which the cool air backs up to form a quasi-stagnant pool 200 to 300 m deep. Inhomogeneous turbulence is a major factor in the transport history of tracers in Anderson Creek. In the slope-wind potion of the basin the plume growth is systematic and about 1.5 to 2 Pasquill-Gifford categories more vigorous than estimated by radiation and windspeed. The slower mean wind and greater meandering that the plume encounters in the cool air pool makes a distinct change in the tracer cloud behavior. Residence times are long and the apparent width of a time integrated plume is much …

The US Department of Energy (DOE) regulations and guidelines for radiation protection have been reviewed and are being applied to the device design. Direct radiation protection is provided by the device shield and the reactor building walls. Radiation from the activated device components and the tritium fuel is to be controlled with shielding, contamination control, and ventilation. The potential release of tritium from the plant has influenced the selection of reactor building and plant designs and specifications. The safety of the plant workers is affected primarily by the radiation from the activated device components and from plasma chamber debris.

The observation, a few years ago, of unexpected large cross sections at backward angles in the elastic scattering of mass-asymmetric heavy ion systems gave us hope that we could learn something new and more precise on the properties of the average ion-ion potential. The subsequent observation of broad regular structures in the elastic and inelastic excitation functions near theta/sub cm/ = 180/sup 0/ were also very promising. Numerous models were proposed to explain some or all the observed features. These models can be divided mainly in two groups. Some try to modify directly the average optical potential whereas others associate the observed cross sections to a modification of specific partial waves outside the scope of the optical potential. This separation in two groups is not always clear since as demonstrated adding a Regge pole to a strongly absorbing potential is under some conditions perfectly equivalent to changing the shape of this potential. Similarly the resonances added to an S matrix can be understood as the manifestation of the potential resonances of a completely different optical potential. We describe recent calculations which have been carried on to try to understand the behavior of the data near the barrier.

The use of short-lived positron emitters such as carbon 11, fluorine 18, nitrogen 13, and oxygen 15, together with positron-emission tomography (PET) for probing the dynamics of physiological and biochemical processes in the normal and diseased states in man is presently an active area of research. One of the pivotal elements for the continued growth and success of PET is the routine delivery of the desired positron emitting labelled compounds. To date, the cyclotron remains the accelerator of choice for production of medically useful radionuclides. The development of the technology to bring the use of cyclotrons to a clinical setting is discussed. (ACR)

This paper describes sources of uncertainty in the data used for calculating dose estimates for the Hiroshima explosion and details a methodology for systematically obtaining best estimates and reduced uncertainties for the radiation doses received. (ACR)

Shielding research in the United States continues to place emphasis on: (1) the development and refinement of shielding design calculational methods and nuclear data; and (2) the performance of confirmation experiments, both to evaluate specific design concepts and to verify specific calculational techniques and input data. The successful prediction of the radiation levels observed within the now-operating Fast Flux Test Facility (FFTF) has demonstrated the validity of this two-pronged approach, which has since been applied to US fast breeder reactor programs and is now being used to determine radiation levels and possible further shielding needs at operating light water reactors, especially under accident conditions. A similar approach is being applied to the back end of the fission fuel cycle to verify that radiation doses at fuel element storage and transportation facilities and within fuel reprocessing plants are kept at acceptable levels without undue economic penalties.

The azimuthal angular distribution of baryon-antibaryon pairs in a quark jet is calculated and compared with experimental data in e/sup +/e/sup -/ annihilation.

We have measured the reflectivity of several multilayer dispersion elements between 80 and 500 eV. Two samples of ReW-C and one of Ni-C with 2d spacing of approximately 70 A and 150 A were tested at angles of incidence between 10/sup 0/ to 80/sup 0/. Measurements were made by fixing the incident and reflected angles (Bragg) and scanning the photon energy. Theoretical analyses of these multilayers have also been made and the results are compared with the experimental measurements.

Details of subsystem costs are among the questions most frequently asked about the $14.4 million Tritium Systems Test Assembly (TSTA) at Los Alamos National Laboratory. This paper presents a breakdown of cost components for each of the 20 major subsystems of TSTA. Also included are details to aid in adjusting the costs to other years, contracting conditions, or system sizes.

The AGS has been brought into operation in October 1982 with multi-turn H/sup -/ charge exchange injection. The injection area of the AGS has been modified to bring the H/sup -/ beam from the 200 MeV linac through the main magnet fringe field to a stripping foil located within the magnet aperture. The injection system is described in detail and initial performance of the accelerator is reported.

Core level angle-resolved photoemission intensity oscillates sinusoidally with increasing photoelectron momentum. Interference between direct and scattered photo-emission causes this angle-resolved photoemission extended fine structure (ARPEFS). We will discuss an analytic single-scattering theory which quantitatively describes the oscillations. The procedures for extracting surface geometry information from photoemission measurements will be illustrated with S(1s) ARPEFS from S on Ni(100) and Cu(100) obtained with the soft X-ray double crystal monochromator at the Stanford Synchrotron Radiation Laboratory. Building on the surface sensitivity and chemical selectivity of photoemission, ARPEFS analysis provides direct geometrical information from the oscillation frequencies (derived with auto-regressive Fourier analysis), from intensity changes with polarization and analyzer position, and from analysis of scattering phase-shift zero-crossings.

It is possible to use the Brookhaven AGS as a heavy ion machine by adding a cyclotron to the Tandem and using this combination as injector. An intermediate step for lighter ions might consist of injecting the Tandem beam directly into the AGS. In either case, quite high intensities should be possible.

A plan has been developed to inject ion beams from the Brookhaven Tandem or a cyclotron added to the Tandem into the AGS. This beam could then be injected into a relativistic heavy ion collider. The availability of many CBA components adds to the attractiveness of this proposal.

Heavy ions accelerated in the AGS can be injected into CBA providing colliding beams up to 400 Q/A GeV/amu. Luminosities approaching 10/sup 28//cm/sup 2/sec should be achievable even though the ions must be accelerated through phase transition. More current might be stacked by using a special ..gamma../sub T/ jump method to avoid the excessive radial aperture usage at transition.

Since 1980 there has been considerable interest at Brookhaven in exploiting the existence of the Colliding Beam Accelerator, CBA, earlier referred to as Isabelle, for the generation of heavy ion collisions at very high energies. The only requirement for a heavy ion collider would have been for an energy booster for the Tandem accelerator and a tunnel and magnet transport system to the AGS. For a few million dollars heavy ions up to nearly 200 GeV/amu could be collided with luminosities of 10/sup 27/ to 10/sup 28//cm/sup 2/ sec in experimental halls with ideal facilities for heavy ion physics studies. Although the CBA project has been stopped, it is still true that Brookhaven has in place enormous advantages for constructing a heavy ion collider. This paper describes a design that exploits those advantages. It uses the tunnel and other civil construction, the refrigerator, vacuum equipment, injection line components, and the magnet design for which there is expertise and a production facility in place. The result is a machine that appears quite different than would a machine designed from first principles without access to these resources but one which is of high performance and of very attractive cost.

This paper describes the current status of the waste package designs for salt repositories. The status of the supporting studies of environment definition, corrosion of containment materials, and leaching of waste forms is also presented. Emphasis is on the results obtained in FY 83 and the planned effort in FY 84. 8 references, 3 figures, 1 table.

This paper summarizes the capabilities and applications of the general-purpose and special-purpose computer programs that have been developed for use in fracture mechanics analyses of HSST pressure vessel experiments. Emphasis is placed on the OCA/USA code, which is designed for analysis of pressurized-thermal-shock (PTS) conditions, and on the ORMGEN/ADINA/ORVIRT system which is used for more general analysis. Fundamental features of these programs are discussed, along with applications to pressure vessel experiments.

A reactor safety issue concerning the overfilling of once-through steam generators leading to combined primary/secondary blowdown has been raised recently. A series of six calculations, performed with the LWR best-estimate code, TRAC-PD2, on a Babcock and Wilcox Plant (TMI-1), was performed to investigate this safety issue. The base calculation assumed runaway main feedwater to one steam generator causing it to overfill and to break the main steam line. Four additional calculations build onto the base case with combinations of a pump-seal failure, a steam-generator tube rupture, and the pilot-operated relief valve not reseating. A sixth calculation involved only the rupture of a single steam-generator tube. The results of these analyses indicate that for the transients investigated, the emergency cooling system provided an adequate make-up coolant flow to mitigate the accidents.

A simple radiation power balance model is used to gain insight into the role of antenna directivity and polarization control when throat launch is used to improve core-heating efficiency and to separate ring heating from core heating. Ray-tracing calculations are used to illustrate energy flow and absorption behavior for various throat-launch positions and angles.