The evolution of fission products from UO/sub 2/ during irradiation at high temperatures is of primary interest to the Gas-cooled Reactor Project. Fuel tests consisting of UO/sub 2/ pellets encapsulated in Inconel or stainless steel were irradiated in the LITR, ORR, and ETR. The capsules were pierced in hot cells, and the gases collected in evacuated systems. Fractions of this gas, of suitable activity for counting, were taken and then analyzed by gamma spectrometry. Larger fractions of gas were analyzed by mass spectrometry. Percentage of gas release varied widely, increasing with temperature, impurity content, oxygen-to-uranium ratio of the UO/sub 2/, and decreasing with bulk density. For high density, stoichiometric UO/sub 2/, the gas release was generally less than 3% up to a temperature of about 2800 deg F, about which it was greatly accelerated. Fuel burn-ups of up to 22,000 Mwd/MT were obtained. Maximum measured central fuel temperatures of 3150 deg F were reached. The lower- density nonstoichiometric UO/sub 2/ released greater amounts of fission gas, particularly Kr/sup 85/. (auth)

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; 9 < 4 6 9 7 ; 6 8 7 6 sting Deactor (MTR) has sought to develop improved, economical, long-life fuel assemblies through a comprehensive study of various fuel compositions, enrichments, claddings, burnable poisons, fuel and poison distributions, and fuelelement geometry optimization. The core materials, including uranium -- aluminum alloys, uranium oxide -aluminum cermets, thorium, thorium oxide, boron, gadolinium, dysprosium, and iridium, are tested in pilot-plant scale by irradiating them as sandwich type sample fuel plates. In the procurement of these sample plates, fabrication techniques were developed and evaluated for incorporation of all the fuels and poisons (except Ir/sub 2/O/sub 3/) into cores of aluminum or aluminum alloys. Methods were developed to minimize "dog-boning" and to produce graded fuels. Some of the sample plate compcsitions have been irradiated to high burn-up, i.e., over 50% of the U/sup 235/ content, and have operated successfully in the MTR for seven or more cycles. The irradiated uranium-- aluminum alloy and uranium oxide-- aluminum cermet fuel plates have shown excellent dimensional stability and good corrosion resistance to long-term irradiation. However, some of the thorium oxide fuel plates failed during one cycle of irradiation because of blistering, rupturing, or forming of pinholes in …

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A summary of the safety precautions, operating techniques, and monitoring methods required for efficient use of the Chemical Technology Division Be facility is presented. (auth)

A test was made to determine the over-all effects of reduced coolant purification on the reactor plant. The effects were increased specific activity, gross gamma activity, and fission product activity of the reactor cooling system. (W.L.H.)

Consideration is given to the possibility that in certain types of processing or storage facilities handling enriched fissionable isotopes the pulsed neutron method can give a useful measure of the subcriticality of the system. The proposed method describes how the concentration and multiplication constant are determined for an assembly of unknown concentrations. Such measurements might be undertaken if high levels indicate the possibility of excessive concentrations of fissionable materials. Experiments were performed at the BSF in which progressively more subcritical configurations of BSR-I fuel elements were assembled. The multiplication constants were measured by the source-and-detector and pulsed-neutron methods. (B.O.G.)

Report discussing "A two-volume table for converting wavelengths in standard air to wavenumbers in vacuum. Wave-numbers are given to the nearest 0.001 K (cm^-1) for wavelengths from 2000 to 7000 A in volume 1, and 7000 A to 1000 m in volume II."

From abstract: "This report describes the design of the mobile nuclear power plant which is to be the prototype of a mobile, low-powered nuclear power plant intended to furnish electrical power in remote locations."

Report documenting experience gained by operating the spare PRTR Primary Process Pump. This includes descriptions of equipment used, testing procedures, and operating history.

Report of the annual conference on weights and measures, hosted by the U.S. National Bureau of Standards in Washington D.C. It includes conference proceedings, a list of attendees, information about committees and officers, and other reports or commentaries discussed at the meetings.

A digital computer program called KICK (K-meson Interaction Coplanarization and Kinematics), which carries out the analysis of complete bubble chamber events, is described.

Two types of enclosed hot junction arrangements are possible with sheathed mineral insulated thermocouples. They are the integral junction and he isolated junction. The integral junction is formed by welding, soldering, brazing or forging the two wires into the end of the sheath. The process forms a good thermal and electrical contact between the three materials.

The ORNL analog computer was used to examine one aspect of a safety system for the EGCR. The thermal behavior of the fuel as a result of increases in reactivity at various power levels and gas flows was examined. Safety actions initiated by wither a flux-minus-flow signal or a reactor outlet gas temperature signal were included in simulation.

During the past year, three papers covering results of a major series of experiments on intergenotype of blood-forming tissue have appeared, demonstrating successful implantation of isologues normal cells in anemic hosts, permanently correcting their genetic defect in hematopoiesis, both with and without irradiation of the host. Heavy host irradiation was shown ineffective as preparations for implantation of homologous cells of widely different antigenic types.