A Lucite model of a multi-stage countercurrent hydroclone solvent extraction apparatus has been constructed and tested with Amsco-water. The diffusivity of Cs 134 tracer in aqueous chloride solution was measured to check the performance of the capillary diffusivity measuring system. The experimental data from four Druhm runs showed that 1/8in. thick graphite liners are usable for reactor temperatures above the boiling point of sodium.

The radiation hazards associated with recycled nuclear reactor fuels will greatly complicate the handling and refabrication of these fuels. This problem is most serious with U-233 and plutonium fuels where the presence of U-232 and the heavier isotopes of plutonium contribute energetic alpha, gamma, and neutron radiations at levels many times that from isotopically pure U-233 and Pu-239. This report summarizes present knowledge of the radiation hazards associated with recycled fuel and the additional data needed to make a thorough evaluation of these hazards.

A method was developed for the determination of osmium by measuring the absorbancy of osmium tetroxide in CHCl3. The osmium is first oxidized to the octavalent state and the osmium tetroxide which is formed is extracted selectively with CHCl3. The ultraviolet absorption spectrum of OsO4 in CHCl3 has a series of absorption bands with peak absorbancies at 282. 289, 297, 304 and 312 mu, and molar absorbancy indices of 1870, 1760, 1640, 1400 and 1000, respectively. For each wavelength the optimum concentration range for the determination of osmium was evaluated by the method of Ringbom. Only chloride and octavalent ruthenium interfere in the determination. By this method, from 0.4, to 3 mg of cesium can be determined with a coefficient of variation of 3 per cent.

Two methods were developed for the determination of uranium metal in UF3 with other fluoride compounds. A simplified method of determination which has a relatively high degree of precision (coefficient of variation 2 per cent) is carried out by decomposing the hydride in an atmosphere of carbon dioxide and subsequently measuring the hydrogen over an aqueous solution of potassium hydroxide. The ignition of the hydride in an atmosphere of oxygen and volumetric measurement of the water at reduced pressures provide a more sensitive method of determination. The coefficient of variation of the latter procedure is 7 per cent. The yield of gas from the reaction of the hydride with ammonia and gaseous hydrogen chloride was found to be neither stoichiometric nor reproducible.

The hardness of several materials that have been considered for use as valve scats and bearings in thorium oxide slurry systems were measured and are reported for comparison with thorium oxide.

These specifications for the fuel assemblies for Core I of the Experimental Gas-Cooled Reactor (EGCR) have been developed for use in procuring the first core loading. A fuel assembly for EGCR consists of a cluster of seven cylindrical fuel elements spaced and supported within a graphite sleeve. Each fuel element consists of a stainless steel tube containing a column of hollow UO2 pellets and having a spacer brazed at the midsection to control the spacing between fuel elements in a cluster. A master specification for the fuel assembly, a supplementary specification for each of the components, and a specification on record keeping during manufacture are included.

The HRT refrigeration system was designed to use Freon-11 (CCI3F) as the refrigerant material in the secondary loop. A Van de Graaff irradiation of this material indicated that serious corrosion problems were probable if Freon were used in the proposed metal system. A survey was made of candidate refrigerants, and Amsco 125-82 and triethyl phosphate were selected for irradiation and physical-property determinations.

A program translates an algebraic language like Algol into the machine language of an electronic computer must perform the following functions.

The IBM-70% code GHT has been programmed for the 7090computer, to be run under control of the IBM-7090 FORTAN Monitor System. By eliminating the use of tapes for intermediate number storage, it has been possible to reduce computing time by a factor of 26 over the 704. A minimum of three tapes are required; one for input, one for output, and the System tape. One scratch tape is required for transient problems, and one punch tape is required if the steady-state temperature distribution is to be punched on cards.