The nuclear characteristics and fuel costs of a number of aqueous homogeneous reactors have been estimated. Most of the reactors studied were cylindrical, two-region power-breeders variously having between 0 and 300 g/l of thorium in the core and between 500 and 1000 g/l of thorium in the blanket. The results of the calculations, including breeding ration, fuel inventories, doubling times, and net fuel costs, are summarized in this report.

A self-contained developmental or the formation of the problem of inelastic neutron scattering by crystals is presented. although nearly all of the methods and results used in the present discussion have appeared in a variety of previously published papers, additional mathematical details are given here which have been found by thee authors to aid in understanding the final results.

The Eyewash program, written by James H. Alexander and Nancy D. Given, provides solutions of reactor criticality problems in spherical geometry by means of the group diffusion method. It employs thirty lethargy groups (plus one thermal group) in nine regions. The input consists principally of specifying the geometrical scaling factor, boundaries and compositions of the various regions, and temperature level. The output includes the value of vc that would render the system critical, the relative fission density distribution, fissions, absorptions, and leakages in each lethargy group in each region, and, if desired, an edit of the flux at each space point, each lethargy, and an edit of the macroscopic cross sections for each lethargy, each region. OCUSOL-A is a minor modification and extension of Eyewash. It provides for the computation and editing, on the supervisory control typewriter, of the total absorptions in selected nuclides in the various regions. This information is useful in the computation of breeding ratios and the preparation of detailed neutron balances, and in the estimation of flux-averaged cross sections for use in estimating the rate of change of concentration of the various nuclides with burn-up. The program also provides for saving and transferring the final fission …

To supply information about the several letdown valves which have been in HRT service, a typical valve plug examined by the Metallurgy Section confirms the belief that chemical attack on the Stellite #6 was occurring. It appears that most of the corrosion was due to rinse solutions, since this phenomenon has not been noted on letdown valves in the HRT Mockup where over 90% of the operating time has been with UO2SO4 solutions.

Radiation level measurements of various HRE fuel system components, made in September, 1956, after 27 moths of storage, are compared with the June, 1954, readings before storage. Measurements were made with a standard cutie pie and results tabulated.

A 10% phosphoric acid solution contain 0.2% "Rodine 45" inhibitor is recommended to be used for the chemical cleaning of the HRT seam and closed colling water systems. Wet storage is recommended for both of these systems. The steam system is to be stored with steam condensate containing 100 ppm hydrazine, and closed cooling water system is to be stored with steam condensate containing 1000 ppm potassium chromate.