The design and constructlon of the shielding facility at Battelle are described. This facility consists of an open pool with a fission plate, an instrument bridge and tower, a control room, and radiation-detection instruments. The shielding pool is located at the end of the thermal column of the Battelle Research Reactor (BRR). The fission plate is 28 in. in diameter and contains approximately 3.5 kg of U/sup 235/. The plate was fabricated from three pieces of highly enriched U and clad with about 25 mils of 2S Al. It generates about 24 w during steady-state reactor operation. The fission spectra of neutrons and gamma rays produced by the fission plate are free from appreclible background radiations. The ratio of thermal to epithermal neutrons impinging upon the fission plate is approximately 67, indicating a low fast-neutron background. Assuming an average energy of 2 Mev for backgrounnd gamma rays results in a ratio of thermal-neutron flux to gamma flux of 16. (auth)

The cause and significance of the changes in chemical composition of the HRT fuel and changes in reactivity during operation, particularly in run 17A, were investigated. It was concluded that a rise in reactor power level causes deposition of U, Cu, and Ni in some hydrolytic process within the core circulation system in a region which is at a position between zero and average nuclear importance. The deposition requires several minutes to several hours and is relatively easily reversiable when the power is lowered. (J.R.D.)

A small, laboratory-sized loop was designed for steady-state radiolytic gas recombination studies. It consists of an electrolysis cell, which simulates the radiolytic gas formed in a reactor, and a bomb for containing slurry under test. The electrolysis capacity of the system is adequate for the study of slurries having recombination rates as high as 10 moles/hr/liter of slurry at the proposed slurry reactor operating conditions. (auth)

Chip method experiments were performed for the preparation of Th - 9 wt.% U, U - 10 wt.% Nb, and Al--16 wt.% U - 0.2 wt.% B alloys. The work on Th-9 wt.% U indicated that the technique was applicable with oniy slight impairment of mechanical properties and slight increase of oxygen content. Experiments on U-10 wt.% Nb to produce a more corrosion-resistant alloy were not successful. The potential use of the chip method in fabricating alloys with a burnable poison such as boron appeared feasible. An aluminum alloy containing 16 wt.% U and 0.2 wt.% B showed good homogeneity. The shot method was used on an alloy of Al-25 wt.% U. The homogeneity and the mechanical properties of this alloy, when extruded, were superior to those of similar alloys produced by conventional melting and casting. Preliminary work on the blending of master alloys of a burnable poison (i.e., boron) with an aluminumuranium alloy indicated the feasibility of obtaining a homogeneous alloy with good mechanlcal properties. (auth)