The advantages of the use of organic liquids in fission reactors to minmize corrosion and pressure problems were studied relative to the solution of thorium in such fluids. Thorio-organic compounds were prepared from organic acids, diketones, and other chelating compounds. Salts of carboxylic and phospho- organic acids were insoluble. The chelate with dibenzoylmethane was soluble in molten biphenyl but was decomposed at 300 deg C. The general low solubility of thorio-organic compounds in nonpolar solvents can be explained by steric effects. The large thorium atom has the ability to form strong coordination complexes with adjacent molecules, leading to coordination polymers. The effect can be minimized by shielding the thorium nucleus with large organic groups such as dibenzoylmethane. The large, branched organic groups needed to impart solubility limit the maximum solubility. (auth)

Cobalt samples frequently are irradiated in nuclear reactors to produce gamma sources and can be irradiated as integral flux monitors because of the long half-life of the isotope produced. At the present time a small cobalt sample is being irradiated within the KW Reactor Snout facility for future use as a radiographic source for inspection of finished product in the Chemical Processing Department. Analysis was made to estimate the buildup of activity in this sample; the general equation may be of interest and value for other cobalt sample irradiations.

Further studies are reported on the analytical behavior and experimental testing of Cs/sup 137/ plaque irradiator designs. Low-level sources used for the initial experiments consisted of about 7 mc of Cs/sup 137/ aqueous solution in brass trays 20 by 20 by 1/2 in. high having wall thicknesses of 1/16 in. Calibration tests were made preliminary to radiation field mapping. (T.R. H.)

The hydrodyraruios code BOCH and the physics code PUREE' were used in the anaiysis of specific VMR cores. Eight core designs of different geometries were selected for initial evaluation. Extensive analysis of the first of these cores was completed. aid more general analysis of the other cores is in progress. The analog representation of the VMR kinetics was completed and applied to the aaalysis of the VMR over a large range of parameters for curves of positive void versus reactivity. Funiner checks of the first three energy groups of PUREE' against experinnental data were completed. The P/sub 3/-POP method of computing the thermal group constants was used in conjunction with the first three groups to analyze the reference core designs and the critical experiment. The more complex blackness method of computing the PUREE' thermal group constants appeared to be functioning properly and is being checked on very tight lattices to determine the magnitude of the change in fuel-pin blackness due to incident neutron distortion by neighboring fuel pins. Mechanical and system design of selected cores was started. Corrosion rate of the moderator systems was computed. and preliminary analysis of a clean-up system was started. (For preceding period see ATL-A-103.) (W.D.M.)