The following report contains two reports to summarize a thesis: first, a report describing the classical moment techniques of Tchebycheff, Markov, and Stieltjes that have been applied to the problem of diagonalizing the Hamiltonian operator; and the second report describes an investigation of the higher-order corrections to the mesic disintegration of deuterons that is considered.

The following report summarizes the results of the laboratory-scale work and pilot-plant scale work of a salt-batch composition that reduces the hydrogen pickup by uranium rods during the beta heat treatment, and the study of the influence of humidity over the salt bath on hydrogen pickup.

Abstract: "In a study of the preparation and properties of delta-phase zirconium hydride it was found that large, sound bodies of the hydride can be prepared by direct combination of the elements if the rate of the reaction is retarded by limiting the supply of available hydrogen. Specimens up to 1-in. diameter were prepared using this technique. Because delta phase zirconium hydride does not readily form eutectics with iron-and nickel-base alloys below 1800 F these materials may be utilized for clodding the hydride. Delta-phase zirconium hydride is unaffected by exposure to liquid NaK or to nitrogen gas at temperatures below 1000 F. The hot hardness of delta-phase zirconium hydrid is about 130 kg per mm-2 at room temperature and 40 kg per mm-2 at 1500 F. The mean coefficient of thermal expansion (68 to 1337 F) is 6.5 x 10^-6 per deg F. The thermal conductivity varies from 5.7 Btu/(ft)(hr)(F) at 300 F to 5.1 Btu/(ft)(hr)(F) at 1300 F."

The following report follows the procedures to compact blends of uranium tetrafluoride and magnesium, describing how lubrication of the compact effects the outcome of the blends.

The following report follows an experimental study that was made on the mass transport of chromium in polythermal inconel-fluoride fuel systems, followed by the technique of adding radioactive chromium-51 to the system as either CrF3 in the salt or as elemental chromium in the solid phase.

A study was conducted to demonstrate the stripping and evaporation steps in a Purex-type uranium recovery process and to ascertain the operating behavior of the equipment under a range of conditions. The factors considered were control, effectiveness, and reliability of equipment and optimum feed point. Experimental procedures are described, and recommendations for equipment modifications are included. (J.R.D.)

A new and rapid method for the liquid-liquid extraction of uranium and plutonium from hydrochloric acid solution is based on the use of tri(iso-octyl)amine dissolved in xylene or methylisobutylketone. Uranium and/or plutonium are separated from thorium, alkalis, alkaline earths, rare earths, zirconium, niobium, ruthenium and other elements which do not form anionic species under the conditions described. The technique may be used for either tracer or macro quantities of uranium. Several practical applications of the method for the separations chemist are proposed.

On May 23, 1957, a visit was made by the writer to the Selas Corporation of American in Dresher, Pennsylvania. The purpose of the visit was to discuss further investigations into methods of tubesheet brazing by direct heating. Original work along these lines has been carried out at ORNL and is covered by a memo (CF-57-4-57) to W.D. Manly, dated April 16, 1957, and entitled : Investigation of Tubesheet Brazing by a Method of Direct Heating.

An estimate has been made of the critical fuel concentration in the HRT, taking into account the effect of the core corrosion sample assembly. The estimate is based on a number of previous calculations of critical concentration in an un-poisoned reactor and one calculation of critical concentration as a function of poison level. The makeup of the first core corrosion sample assembly was used in calculating equivalent neutron poisoning effects. Figure 1 shows the estimated critical concentration as a function of temperature with the corrosion sample assembly in place. At 280°C, the assembly raises the critical concentration by 0.6 g U-235/kg D2O. This effect is equivalent to a uniformly distributed poison equal to 4.1% of the fission cross section. The equivalent poison is greater at lower temperatures, where the uranium concentration is lower.