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CERAMIC NUCLEAR FUELS IN THE SYSTEM ZrO$sub 2$-CaO-UO$sub 2$. Final Report

Description: Potential nuclear fuels in the system ZrO/sub 2/-CaO-UO/sub 2/ were investigated. Cubic fluorite-type solid solutions, as indicated by x-ray diffraction patterns, were formed by sintering CaO-stabilized ZrO/sub 2/ and U/ sub 3/O/sub 8/ compacts in either air or H/sub 2/. A continuous solid solution was found between urania and stabilized zirconia with H/sub 2/ sintering at 1750 deg C. Air sintering produced a limited region of solid solution in the stabilized zirconia portion of the system at 1450 deg C. Results on phase identification, oxidation behavior, and water corrosion are presented. (auth)
Date: September 1, 1962
Creator: Handwerk, J.H.; White, G.D. & Hill, D.C.
Partner: UNT Libraries Government Documents Department

IRRADIATION TESTING OF CERAMIC FUELS. Summary Report

Description: S>A research program was completed on the composition limits for single- phase face-centered cubic crystal structures in the ZrO/sub 2/-rich region of UO/ sub 2/-CaO-- ZrO/sub 2/ and in the CeO/sub 2/-rich end of UO/sub 2/-- CeO/sub 2/, on the fabrication of highdensity pellets from these cubic compositions of both systems, on the properties of these cubic compositions, and on the irradiation stability of these compositions. Phase studies are reported that confirm the occurrence of cubic regions in both UO/sub 2/-- ZrO/sub 2/-- CaO and UO/sub 2/-- CeO/sub 2/. The properties measured include thermal conductivity, thermal performance testing, melting points, and corrosion in water and steam. Progress in the irradiation program is described. (D. L. C.)
Date: September 1, 1962
Creator: Zuromsky, G & Chernock, W P
Partner: UNT Libraries Government Documents Department

SWELLING OF URANIUM AND URANIUM ALLOYS ON POSTIRRADIATION ANNEALING

Description: The swelling of U and of a few selected U alloys on postirradiation annealing was investigated by utilizing density measurements in conjunction with the observation of pores in the microstructures of annealed specimens. Speciniens were irradiated to about 0.3 at.% burnup in a constrained condition at approximately 275 deg C and were subsequently pulse annealed. The amount of swelling was found to be less than 1% for U specimens that were pulse annealed up to 75 hr at temperatures below 550 deg C; the amount of swelling, however, increased considerably on annealing at temperatures between 550 and 650 deg C. Specimens pulse annealed up to 75 hr at 618 deg C decreased in density by approximately 18%. The swelling was accompanied by the formation of bubbles on grain boundaries in recrystallized regions. The observations suggest that recrystallization is a necessary prerequisite for pronounced swelling in the alpha phase. Uranium specimens pulse annealed up to 75 hr at temperatures between 650 and 750 deg C in the BETA phase decreased in density by about 5%. Specimens annealed in the BETA phase, in contrast with those annealed at 618 deg C in the alpha phase, were badly cracked and contained pores of a smaller diameter, which were uniformly distributed within the grains. A specimen pulse annealed up to 16 hr at 822 deg C decreased in density, by, about 20%. This heat treatment produced pores of large diameter, located along grain boundaries, as well as pores of smaller diameter, distributed uniformly within the grains. Uranium alloys containing between 1 wt% and 9 wt% of either Ti, Zr, Nb, or Mo generally swelled more than pure U on pulse annealing up to 75 hr at 618 deg C and 740 deg C. An exception was the behavior of a U --4.0 wt % ...
Date: September 1, 1962
Creator: Loomis, B.A. & Pracht, D.W.
Partner: UNT Libraries Government Documents Department