The work described in this report was done to determine the path of decomposition of plutonium (IV) oxalate and to determine the factors affecting the reactivity of the oxide with the hydrogen fluoride.

Contemplated higher tube power for future reactor operation will probably require a fuel element jacketing material more corrosion resistant than presently available aluminum alloys. Zirconium and its alloys are generally regarded as the most promising jacketing candidates for high temperature operation, particularly for exposures of long duration. In order to obtain assembly, welding, and corrosion data, twenty Al-Si bonded and twenty unbonded Zircaloy fuel elements were prepared for KER loop testing. This report describes the technique developed to weld Zircaloy jacketed fuel elements and presents the results of end closure corrosion testing and metallographic examination.

Past experience has shown that the demand for increase separations plant capacity comes up very regularly. One of the variables which greatly affects plant capacity is cross-sectional area of the individual vessels. Larger areas permit greater flow rates as well as more space for the installation of heat transfer piping (shell and tube concentrators). Design considerations of the separations plants vessels have been based on both circular cylinder and slab geometries. A study has been made to determine other vessel geometries that will result in safe vessels from a nuclear safety standpoint and at the same time offer larger cross-sectional areas than right circular cylinders. Vessels of elliptic as well as annular cross sections have been considered. It is neither the intent of this study to discuss the effects of intersection, vessel piping, etc., nor the pros and cons of fabricating feasibility and structural strength of these different shaped vessels. The main purpose is to make comparisons of cross-sectional areas (capacity parameter) of safe vessels so that vessel shape may be evaluated as one of the parameters in any design study for separation plants.

An experiment designed to evaluate the in-pile performance of the U-Mg fuel material when irradiated to high burnups has been completed. Twelve specimens of the fuel material which contained uranium particles that packed 50 volume per cent, (91.5 weight per cent), uranium in a magnesium matrix were canned in Zircaloy cans and irradiated in the Materials Testing Reactor to 0.1 (1000 MWD/T), 0.3 (5000 MWD/T), 1.0 (10000 MWD/T) and 2.0 20000 MWD/T) per cent burnup of the total uranium atoms; more exactly, 1 MWD/T = 1.16 x 10⁻⁴ per cent burnup of the total uranium atoms. Irradiation of the twelve capsules began on August 1, 1954. The burnup figures used in this report are calculated values assuming a conversion ratio for the capsules of 1.0. Because of the lack of confirmed experimental burnup data for exposures of this magnitude, there is a possible error in the calculated values of about 20 per cent at 2.0 per cent burnup. However, recent results based on chemical analysis for cesium indicate that the calculated values of burnup agree quite closely for the higher exposures. Burnup estimates based on the results of the chemical analysis will be published when they become available. Six of …

Studies are described of the percutaneous absorption and gastrointestinal absorption in the rat of ruthenium administered in the form of "insoluble particulates." Results are also reported on the gastrointestinal holdup of these particulates.

For some time, it has been the opinion of the personnel of this laboratory and other investigators that an appreciable amount of the corrosion observed on stainless steel in nitric acid solutions might be due to the presence of some of the lower oxides of nitrogen; NO-, NO-2, etc. If this assumption is correct, the elimination of these compounds from process solutions should result in a significant increase in the service life of equipment handling nitric acid, such as acid fractionators. Since the corrosion problems experienced in acid fractionators and concentrators are very severe, an investigation of this theory becomes highly desirable. The purpose of this report is to summarize the work performed, to date, by this laboratory in the investigation of the inhibition of nitric acid corrosion of stainless steel.