The purpose of this work was to investigate the possibilities of producing a plastic bonded explosive having greater mechanical strength than that of presently existing plastic bonded explosives. This interim report details activities and progress through July 15, 1957.

Losses have been determined for flow through models of various proposed core sub-assemblies as part of a study of the elements of a nuclear reactor. Six core sections and two? axial blanket sub-assemblies have been compared on the basis of drop in piezometric. head or pressure drop. The core sub-assemblies are composed of an entrance nozzle, a lower axial blanket section, the core section, an upper axial blanket section, and a short section for the handling lug. The four parts of the sub-assembly other than the core section are designated as the axial blanket sub-assembly. In each core section there are 144 rods within a container which has a square cross-section. The primary differences between one core section and another are the means qf supporting and spacing the rods. Bars or wires wrapped in spirals around the rods were used as well as a series of grids made up of wires and supported at the four corners. Also, in one core an, inner wall was used to provide an annular flow passage which helps to reduce the difference in temperature at the inner and outer walls of the core. The two axial blanket sub-assemblies tested are similar except ?that the …

An evaluation of core materials for a gas-cooled reactor is being made. Work on the ZrH/sub n/ moderator has been confined to the high-hydrogen or delta- phase material. Methods for preparing sound hydride bodies of the highhydrogen composition have been developed. Both solid hydride and hydride powder compacts are being clad by a pressure-bonding technique. The hot hardness, tensile strength, thermal conductivity, thermal-expansion coefficient, and dissociation pressure of the delta-phase material are being determined. Control-material development was directed at rare-earth-oxide dispersions in Ni-chrome V or Co alloys. The reference fuel element is dispersedUO/sub 2/ in stainless steel. Studies include work on fabrication techniques and irradiation damage, and physical- and mechanical-property determinations. Several alternate fuels are being investigated. Gas-coolant studies involve N-metal and NH/sub 4/-metal reactions. Several additives to retard nitriding are being investigated. An in- pile-loop facility for testing reference materials is being constructed for operation in the Battelle Research Reactor. (auth)

The thermal cycling, irradiation behavior, and fabrication characteristics of U are strongly dependent upon grain size; a smaller grain size yields the better properties. Grain refinement of cast U may be accomplished either by hot working in the high alpha temperature range or by heat treatment; refinement by the latter method was the object of this investigation. The variables studied were time, temperature, specimen size, multiple quenching, and alphaannealing after quenching. The results of the investigation have led to the following conclusions, within the scope of the experimental conditions. The grain size of cast U may be appreciably refined by beta-quenching. Time and temperature in the beta phase are not significant in determining the final alpha grain size. Multiple beta-quenches (two to four times) produce better grain size refinement than a single quench. Alpha-annealing after beta-quenching causes recrystallization, but does not greatly affect the grain size. Gamma-quenching is not recommended as a practical heat treatment. (auth)

Radioactive contamination was confined and controlled in an isolation tank when irradiated plates of natural U were cut under water. (auth)

Progress is reported on the following studies: development of materials for Hanford reactors, developments for Al-clad fuel elements, studies of Zr-U alloys, corrosion studies of Zr, reactor-materials development, physical metallurgy, corrosion problems associated with the recovery of spent reactor fuel elements, evaluation of a reflector-controlled heterogeneous boiling reactor, studies of Na-Ta compatibility at elevated temperatures, and de velopment studies for the PWR. (For preceding period see BMI-1189.) (W.L.H.)

The effect of deuterium oxide (D{sub 2}O) on the survival of mice inoculated with Ehrlich's mouse ascites tumor has been studied. Mice maintained on 25% and 30% D{sub 2}O drinking water showed an improved survival time of about 6 days whereas 40% D{sub 2}O drinking water had no effect on survival time. The effect is interpreted in terms of inhibition of tumor cell division and systemic toxicity.

In this paper experiments a r e reported on annihilation and scattering of antiprotons in H{sub 2}O , D{sub 2}O, and O{sub 2}. From the data measured i t i s possible to obtain an antiproton-proton and a n antiproton-deuteron c r o s s section a t 457 Mev (lab). Further analysis gives the p-p and p-n c r o s s sections a s 104 mb for the H-p reaction c r o s s section and 113 mb for the p-n reaction c r o s s section. The respective annihilation cross sections a r e 89 and 74 mb. The Glauber correction necessary in order to pass from the p-d to the p-n c r o s s section by subtraction of the p-p c r o s s section i s unfortunately large and somewhat uncertain. The data a r e compared with the p-p and p-n c r o s s sections and with other results on p - p collisions.

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The luminescence of various chlorophyll-containing plant materials has been investigated under a variety of conditions. The results have been shown to be consistent with a mechanism involving the recombination of electrons and holes trapped in a quasi-crystalline lattice. Some details of such a mechanism have been proposed which suggest the mode of entry of the light energy into the photosynthetic pathway.

Experiments are described that have been designed to measure separately annihilation and reaction cross sections for antiprotons of approximately 450 MeV on oxygen, copper, silver, and lead. A new and more luminous spectrograph has been built for this experiment. The antiproton cross sections a r e compared with total proton cross sections, and are found to be larger by a factor varying from 1.74 for oxygen to 1.39 for silver. Calculations based on the optical model give a reasonable connection between these cross sections and the 6-p and 6-n cross sections. Finally, the information available on antiproton production cross sections is collected. There are indications that a free nucleon is several times as effective as a bound one for producing antiprotons.

Shield weights were calculated for a number of fast reactors having desirable engineering characteristics using the Shield Optimization code. On the basis of these calculations, a Design Fast Reactor was chosen. This reactor, henceforth known as the PWAR-9, has a 12.75 inch core O.R. with a 2 inch Ni reflector. The reactor-shield weight and weight components for a supersonic mission, 2 man crew compartment, are given in table 1. The rpesent shield design uses U and LiR as shielding materials on the reactor and U and plastic on the crew compartment. No intermediate heat exchanger is used since hot Na is pumped directly to the engines. The dose from the activated Na is taken into account by putting more shielding on the crew compartment. No patch weights on the reactor have been added since it is estimated that little will be needed.

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The feasibility of a 150 Mwe aqueous homogeneous nuclear power plant was investigated by a joint study team of the Nuclear Power Group and The Babcock & Wilcox Company. In this concept, the reactor is a single-fluid two-region design in which the fuel solution circulates through the thoria pellet blanket as the coolant. Componeats and plant arrangement were designed to provide maximum overhead accessibility for maintenance. All components in contact with reactor fuel at high pressure are themselves enclosed in close-fitting high-pressure containment envelopes. (auth)

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The second All-Ti loop, 1OOA loop H, was placed in operation for more than 400 hr with UO/sub 2/SO/sub 4/ solution at 250 deg C and -- 1000 psi. A fourth test of the mockup of the Zircaloy-2--stainless steel transition joint used in the HRT reactor vessel was completed. The joint and bellows functioned properly and were leaktight. The series of long-term runs at 200, 250, and 300 deg C with solution proposed for use in the HRT was concluded. Stainless steel and Ti stress specimens exposed during the latter 13,000 hr of these tests gave no evidence of stress-corrosion cracking. Results of a study of the effect of heat treatment on corrosion of type 347 stainless steel are presented. Pretreatment of stainless steel for 100 hr at 250 deg C with oxygenated H/sub 2/O containing 100 or 200 ppm Cr/sup 6+/ as CrO/sub 3/ decreased initial weight losses on subsequent exposures to UO/sub 2/SO/sub 4/ solutions. Stress-corrosion cracking of stainless steel in UO/sub 2/SO/sub 4/ solutions is described. A number of alloys of Zr were corrosion tested in simulated HRT core solutions at 300 deg C. Type 347 stainless steel, surface hardened either by malcomizing or Thermospray 16-C, corroded …

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A method is described for routine urinalysis for Po by plating on copper at room temperature from acid solution. A discussion is presented based on experience gained by this laboratory in working with the method over a four-year period. (auth)