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The Fuel Cycle Program is an integrated program of investigation in the Vallecitos Boiling Water Reactor (VBWR) and other facilities to improve the technological limits of boiling water reactors in several areas. This report presents updates on tasks related to those areas.

A frequency analysis was made of the VBWR stability test data. Interpretation of the steady-state noise observed in the stability tests involved consideration of several possible sources of excitation. One of these, a theory of water surface waves, is summarized. Visual and destructive examinations were made of selected fuel rods. Fretting corrosion of the Zircaloy-clad fuel rods against stainless steel spacers was observed. Evidence that UO/sub 2/ thermal conductivity increases with time was obtained. Hot gas isotatic pressed fuel rods failed after 316 Mwd/T irradiation and 5 months storage under water. Shakedown operation of a 7-rod test section for measuring burnout heat flux was conducted. A comparison of measured and calculated isotopic composition for uranium and plutonium isotopes after 400 Mwd/T irradiation indicated that the calculations underestimate capture in U/sup 238/ and overestimate capture in Pu/ sup 239/. Flux wire irradiations provided axial and radial flux profiles and the ratio of thermal to fast flux as a function of axial position. (M.C.G.)

Paper presented at American Nuclear Society Meeting, June I8-21, 1962, Boston, Mass. Design and operating problems of unclad and ceramic gas-cooled reactor fuels in high temperature circulating gas systems will be studied using a test facility now nearing completion at the Oak Ridge Research Reactor. A shielded air-tight cell houses a closed circuit gas system equipped for dealing with fission products circulating in the gas. Experiments can be conducted on fuel element performance and stability, fission product deposition, gas clean up, activity levels, component and system performance and shielding, and decontamination and maintenance of system hardware. (auth)

A generalized least-squares technique can be used to calculate equilibrium constants in solvent extraction equilibria by minimizing the difference between observed and calculated distribution ratios. The method was successfully applied to the extraction of uranyl nitrate and nitric acid by TBP dissolved in an inert diluent. (auth)

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Computations of proton recoil energy losses from neutron irradiation of hydrogenous systems possessing plane symmetry were made for the purpose of fast neutron counter design. A digital computer code was written to carry out the calculations for two irradiation geometries: the neutron beam is assumed to be normally incident upon the system, and the system is exposed to an isotropic flux of neutrons. Numerical results are presented for neutrons of various energies incident on plane radiators of different thicknesses for these two irradiation geometries. These results were used in the conceptual design of fast neutron dosimeters employing a generalized dosimetry principle. (auth)