A method of designing a two-layer pressure vessel is presented wherein contact between the layers is produced by controlled yielding of the inner vessel by internal pressure. The amount of prestress depends upon the dimensions of the vessel, the properties of the material of construction, and the prestressing pressure. The method takes into account the actual stress-strain curve of the material and satisfies the rales of plastic flow with work hardening. (auth)

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The radiation intensities from shielded and unshielded sources fabricated from seventeen isotopes that show promise for use in isotopic power or radiation applications were calculated. Source sizes in the range of 100 to 20,000 thermal watts were evaluated. All shielded sources were assumed to be attenuated by Fe, Pb, and U; and in those cases where the source also emitted neutrons, neutron and gamma attenuation through water was determined. The isotopes studied and their physical form are as follows: /sup 60/Co (metal), /sup 85/Kr (liquefied gas), /sup 90/Sr (oxide and titanate), Zr-/sup 95/Nb (oxide), / sup 106/Ru (metal), /sup 137/Cs (glass), /sup 144/Ce (ox ide), /sup 147/Pm (oxide), /sup 170/Tm and /sup 171/Tm (both as oxides), /sup 204/Tl (metal), /sup 210/Po (metal matrix with void space for gas collection), /sup 232/U (oxide), /sup 228/Th (oxide matrix with void space for gas collection), /sup 238/Pu (oxide), /sup 242/Cm (oxide matrix with void space for gas collection), and / sup 244/Cm (oxide). The use of the graphical results to calculate separation distance, shield thickness, and shield weight is demonstrated. (auth)

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S>The computer program SNAPWN VI is described which solves the space- independent reactor kinetics equations with feedback equations representing the principal shutdown mechanisms in a SNAP reactor. Reflector delay effects are treated by a reflector group model. By using an alternate main program and two alternate subroutines, spatially dependert feedback effects may be considered. Printed, CRT, and punchcard output may be obtained optionally. Sample problems are demonstrated for both versions of the code. The equations and listings are included. (auth)

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The volatility of UO/sub 2 plus or minus x/ and the phase relations in the uranium-oxygen system were studied using thermogravimetric techniques. Chemical reactions describing the loss of uranium from UO/sub 2 plus or minus x/ at temperatures between 1100 and 2200 deg C in oxygen pressures between approximately 10 and 10/sup -6/ torr are proposed. The uranium-bearing vapor species above UO/sub 2 plus or minus x/ appears to be UO/sub 4/(g). Evidence supporting the existence of UO/sub 4/(g) included the volatilization of material with an oxygen-to-uranium ratio of 4 during the decomposition of UO/sub 2 plus or minus x/ (0.2 > x > 0) to near-stoichiometric UO/sub 2/ in vacuum above 1500 deg C and the dependence of the evaporation rate of the uranium dioxide on the oxygen pressure between 1200 and 1500 deg C. The equilibrium oxygen pressures over compositions between UO/sub 2.02/ and UO/sub 2.63/ in the UO/sub 2+x/ and U/ sub 3/O/sub 8/- regions and over the boundary between these phases were measured between 1000 and 1600 deg C. The equilibrium oxygen-to-uranium ratio of UO/sub 2 plus or minus x/ was less than 2 above 1700 deg C in vacuum. (auth)

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Neutron microscopic cross sections for tantalum are presented in the nine-group format. (auth)

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Gamma production cross sections are presented as a function of l6 neutron lethargy groups and 11 photon energy groups for 13 elements and isotopes. They were computed by the program GAMMA-P and account for the production of gamma rays by neutron radiative capture, neutron inelastic scattering, neutron induced fissioning, and (n, alpha ) reactions. (auth)

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