Equations governing the variation of U235. U238, Pu239, Pu240, and Pu241 have been derived and their solutions plotted as a function of irradiation time. The initial U235 content of the uranium was varied from 0.5% to 2.0%. The range of conversion ratios was from 0.5 to 1.2. The irradiation was from 0 to 20,000 mwd/ton of fuel. Since a range of initial conversion ratios is associated with each value of enrichment, a solution results in a family of curves for each isotope, and, since the range of enrichments is large, the number of curves is quite large. Translation of the isotope curves to reactivity variation necessitates a calculation requiring a modest amount of time for a particular case but a prohibitive amount of time to cover the entire range of possible combinations of enrichment and initial conversion ratios. Reactivity variation as a function of irradiation time has been computed for a natural uranium reactor with an initial conversion ratio ranging from 0.7 to 1.2 and for 3 types of reactors in which there is a considerable current interest. Similar calculations for other reactors can be made by making use of the isotope curves and the calculation technique set forth in …

Report issued by the Argonne National Laboratory covering the quarterly report from the Reactor Engineering Division. A summary of reactor programs, designs, development, and experiments are presented. This report includes tables, illustrations, and photographs.

This quarterly report discusses ongoing research and experiments at Oak Ridge National Laboratory in the Metallurgy Division. This report discusses water cooled reactors, liquid metal cooled reactors, reactor development metallurgy, basic metallurgy, applied metallurgy, and aqueous corrosion.

Thermal cycling tests on uranium have shown that the dimensional changes that occur on cycling in the alpha range are directly related to both the texture of the material and its grain size: cold rolled rods generally elongate in the direction of rolling, while the same rods, after a beta-treatment, grow at rates several orders of magnitude lower. This considerable improvement by beta-treatment has been attributed to the texture randomization accompanying the heat-treatment. In the course of this heat-treatment, however, considerable grain growth occurs, which ahs the effect of causing surface roughening on cycling (also referred to as "bumping"); fine grained material generally retains a smooth surface. These observations led to the speculation that the most desirable structure in uranium, from standpoint of dimensional stability, is one that combines both a random texture and a fine grain size. Heat treatment of rolled rod offered no easy method to obtain such a product; powder metallurgical techniques, however, appeared ideally suited for the purpose. To this end, early in 1949, the Sylvania Electric Products Company initiated a program to develop suitable techniques for producing uranium powder compacts having the above-mentioned desired characteristics. Because of the availability of thermal cycling equipment at Argonne, …

Deposits of corrosion products form on heat transfer surfaces and in radiation flux zones at temperatures around 500F in stainless steel systems operating with circulating water. The report considers the possible harmful effects of such deposits on heat transfer and fluid flow, as well as factors involved in the origin of these corrosion products and in the mechanisms of deposition. The prevention of deposition by chemical, mechanical, and electrostatic methods is discussed.

Uranium alloys containing 3 and 6 w/o niobium have been prepared in which the impurity content is rather low. These alloys show very promising resistance to corrosion by water at 260 and 300 degree C. The corrosion resistance is exhibited in degassed water and in water which is saturated with air or oxygen at room temperature before testing.

An improved continuous ether extractor is described. The modifications include a means of safely disposing of the active raffinate and a means of positivity checking the raffinate for completeness of uranium extraction. The results obtained on synthetic samples and on dissolver solutions are given. This work was undertaken because of a need for the determination of uranium in dissolver solutions with an accuracy of 0.1 per cent. After a review of available methods it was decided that a gravimetric determination would meet the requirements of precision and accuracy.

Corrosion-stability tests have been made in static autoclaves at 500 and 600F on solutions of compounds having high neutron cross sections to evaluate their usefulness for shutdown purposes. The only compound tested which appeared to be completely stable in 600F water was boric acid. Limited corrosion data did not show it to cause excessive corrosion of zirconium or stainless steel.

The ZPR-I is a facility to study low power critical assemblies using enriched uranium as fuel, having a light water moderator and an essentially infinite water reflector on all sides. The fuel is held in elements 43" long with a 1" square cross section. Any of these elements may be placed in or removed from any position in the reactor tank. Thus, any desired core configuration may be easily obtained.

In the course of the development at Argonne of high purity uranium metal in ingot form, some questions arose as to the validity of the chemical analyses of some of the impurities (particularly those for carbon, boron, and silicon), with one analytical laboratory reporting concentrations in some instances of an order of magnitude greater than another laboratory. Since the low concentrations of impurities in this material involved, in some cases, the development of modified analytical procedures and standards, it was decided to check these discrepancies by having identically prepared samples analyzed by several AEC and associated laboratories. This report is a compilation of the results obtained.

This report is a record of experimentation conducted intermittently over a period of two years and directed toward preventing deposition of transport corrosion products on fuel elements and other critical components in high-temperature, circulating water nuclear reactor. It includes the postulated mechanism for deposition, a description of experimental equipment, experimental data, results obtained from the experiments, and recommendations for future study.

The purpose of this work was to study reagents which might be effective in dissolving uranium oxide produced during slug failures in water-cooled reactor systems. An aspect of this problem which has subsequently become of primary importance is the solubility or transportability of the oxide in pure water.

Report issued by the Argonne National Laboratory covering the quarterly report from the Reactor Engineering Division. A summary of reactor programs (including the Power Breeder Reactor (PBR) and the Central Station Water Reactor (CSWR)), designs, development, and experiments are presented. This report includes tables, illustrations, and photographs.

Surrounding the core of the Experimental Breeder Reactor (EBR) is located the Internal Blanket (see Figure 2 of Reference 1). This blanket is compromised of natural uranium rods jacketed in stainless steel. The active portion of each rod is made up of five natural uranium slugs 0.873" diameter x 4.050" long. The slugs, stacked one of top of another, are held together and protected by a drawn-on stainless steel tube with welded and closures. These internal blanket rods are located inside the external blanket the manufacture of which has been described previously.

The development of methods which were successful in producing zirconium Hanford type process tubing by roll forming and inert are welding (He) flat strip to which appropriate rails had ben previously attached by resistance welding is described in this report. Grade 2 drip arc melted crystal bar material was used.

The rolling and recrystallization textures in 300 C rolled uranium sheet were investigated using a Geiger counter diffractometer with the modified Schulz reflection technique. Seven sections of sheet material were used in order to obtain sufficient data for quantitative pole figures by the reflection technique. A special integrating specimen table was used for obtaining and recording the data atomically.

A plutonium-aluminum alloy containing 4 atom per cent aluminum showed no attack after exposure to purified NaK for one month at 400 C in the absence of any oxide. The same specimen and other plutonium alloys, including pure plutonium, showed marked deterioration in shorter exposure in the presence of oxide films from a welded stainless steel container. Pure uranium was resistant even in the presence of such oxides.

A method is described for preparing plaster of Paris replicas of irradiated fuel slugs. An impression mold is made by pouring the plaster about a fuel slug held in a specially designed holder. The slug is removed from the holder and the impression mold issued to cast a replica, also made of plaster of Paris. The replicas, including one end only, are accurate reproduction of the original slug for surface features down to about one-half mil and for dimensions within one or two mills. Two dental impression plasters were found to give satisfactory results. With the limits mentioned, the process will serve the purpose of preserving models of radioactive specimens for use as "museum pieces." However, the procedures are very exacting in achieving such results.

Report issued by the Argonne National Laboratory covering the quarterly report from the Reactor Engineering Division. A summary of reactor programs, designs, development, and experiments are presented. This report includes tables, illustrations, and photographs.

Report describing the research and development activities related to nuclear chemistry and radiochemistry and basic chemistry conducted by the Argonne National Laboratory Chemistry Division, Section C-1.

A spectrometer has been used with a hollow prism electrically heated to 70 C to measure the refractive indices of solutions of uranium hexafluoride in bromine trifluoride and uranium hexafluoride in bromine pentafluoride. The refractive indices of the two binary systems have been expressed as a function of composition.

The general program established at Argonne National Laboratory in connection with the Fast Power Breeder Reactor (PBR) includes performance of exponential experiments on assemblies having compositions which may exist in the reactor core. This report deals with that phase of the program known as the Fast Exponential Experiment which may be described very briefly as follows. An assembly of fissile (U-235) and fertile material (too small to be self-critical) intermixed with poisons (such as are encountered in the mechanical structure and coolant system of a self-sustaining reactor) is fed with neutrons from an auxiliary source. By measurements of the neutron flux within the assembly, important parameters can be calculated which are necessary to the proport design of an actual critical reactor of the same composition.

This report describes the first estimation of the beta half-life of Pu241 and was made by determining the beta activity associated with plutonium formed by (d,xn) reactions on U258.

The report is the third in a series of interim reports on the climatological studies which are being conducted at the Argonne National Laboratory. First report appeared as document ANL-4538 and covered the period July, 1949 through June, 1950; the second report, ANL-4793, covered the period July, 1950 through June, 1951. These annual reports are offered for purposes of information only; broad conclusions regarding the climate of this site must await the accumulation of a statistically significant amount of data.