A core parameter study of the operating costs was performed for a 300- Mwe sodium graphite reactor, a scale-up of the Hallam Power Reactor. The results of the study indicate that the core design is nsar optimum and that core modifications would reduce the power costs by less than 5%. The lattice spacing, fuel rod diameter, and sodium flow can be varied within a rather broad range without significant changes in power generation costs. The effect of the fuel cladning thickness is more significant; fuel cycle costs can be reduced if stainless steel canning is replaced with zirconium canning. Use of UC in place of uraniummolybdenum fuel would also permit cost reductions. (D.L.C.)

The physical limitations of existing storage tanks for radioactive wastes from separations plants are defined as a guide for preparing process and operating criteria for the existing tank forms to assure continued integrity of the tanks. A "safe-load" curve for each of the four groups of tanks based on current technology is presented. Loading conditions, operation procedures, and thermal stresses are discussed. (M.C.G.)

This document details activities of the irradiation processing department during the month of September, 1959. A general summary is included at the start of the report, after which the report is divided into the following sections: Research and Engineering Operations; Production and Reactor Operations; Facilities Engineering Operation; Employee Relations Operation; and Financial Operation.

Continued process improvements in the separation plants provide an incentive for economics in waste storage costs by utilizing existing facilities to their maximum capability consistent with the radiological hazards involved. The major improvements have reduced waste volumes resulting in increased fission product concentration and energy potential. Analyses have been made to determine the effect of this change on the integrity of the existing structures.

The calculation of shielding the thickness for plutonium is complicated by the many different energies represented in the gamma radiation emitted during decay of the plutonium isotopes. Dose rate predictions are also frequently confused by gamma from varying content of fission product impurities in the plutonium, as well as other gamma radiation induced through alpha and neutron particle absorption within the source material or its environment. After assumptions are made for these many factors the radiation data for shielding determination is still frequently inadequate because of wide variations in dose rates resulting from self-absorption. The degree if self-shielding is in turn dependent on nature of the plutonium compound, degree of compactness, weight, and over-all geometrical distribution of the source material. By preparing a variety of plutonium samples representing combinations of these varying factors, actual dose rates and gamma spectra, as obtained from them, can then be extrapolated for application to specific situations.

The NPR design calls for carbon steel to be the major constituent in the reactor coolant piping system. The piping and its associated fittings will, in all likelihood, be exposed to atmospheric weather conditions during the period of reactor construction. This type of exposure causes rusting. From experience gained during the startup of KER Loop 1 it is expected that there will be initially high NPR coolant activity levels. The high activity during the startup of KER Loop 1 was partially caused by the activation of rust that was eroded from pipe walls. Prevention of rusting on the carbon steel prior to its introduction into the coolant system would reduce the initial activity levels.