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.

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.

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.

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 fuel element to be used in the Savannah River reactors is a natural uranium slug 1.00 in. in diameter and 8 in. long, encased in a 2S aluminum can 1.080 in. O.D. having a wall thickness of 0.035 in. The slug is bonded to the can with an aluminum silicon alloy, using the Hanford Al-Si process.

The feasibility of cladding plate type, corrosion resistant uranium-niobium fuel elements with Zircaloy-II by roll bonding has been demonstrated. Plates with cores of uranium alloyed with 3 w/o and 6 w/o Nb intended for irradiation testing in a high temperature water test loop in the MTR have been finished withing specified tolerances. The preparation of cladding billet core and clad components and the assembly of billets by enclosing cores in welded Zircaloy-II jackets can be readily accomplished with conventional fabrication equipment. Some machining operations and billet evacuations, as used in the preparation of most picture frame billet assemblies have been eliminated. Roll bonds were obtained with reductions of 75% to 80% in thickness. Reductions in excess of 90% in thickness, although not necessary for bonding , can be used for economical productions of long plates. Plates can be made with clad to core bond strengths from 30,000 psi to 60,000 psi. Properly heat treated plates have sufficient ductility to allow cold finishing by rolling, forming, bending, or twisting, with reductions of 20% to 30%. Edge bonds of Zircaloy to Zircaloy have been obtained which were corrosion resistant to 260 C water. End seals which were also corrosion resistant to water …