Multigroup one-dimensional calculations were done recently to obtain estimates of critical masses, power density distributions and fissioning spectra for some homogeneous molten salt reactors having outer reflectors and central "islands," placed inside the currently proposed MSRE vessel. For a 5-inch-thick outer reflector and 1-ft-diamter island, both beryllium, the calculated critical mass is 108 kg; 40 percent of the fissions occur at thermal, and the maximum power density of 3.9 times the core mean power density occurs at the island-salt interface. If the reflector thickness is increased to 10 inches, the critical mass is reduced to 34 kg; 67 percent of the fissions occur at thermal, and the peak power density of twice the core mean again occurs at the core island-salt interface.

Methods for the noncorrosive removal of volatile fission products and UO2 dust from carbon steel and stainless steel have been developed. Procedures for applying these methods to the decontamination of the EGCR charge and service machines are described.

A conductometric titration method described by Goldstein was adapted for use in a remote analytical facility. The results obtained by mean of experiments made prior to this adaptation indicated that methanol is the most satisfactory medium in which to determine excess sulfuric acid in uranyl sulfate solutions that stimulate Homogeneous Reactor type fuel. When methanol is used, the complexation of hydrolyzable ions with sodium fluoride, as described by Pepkowitz, Sabol, and Dustin, is not required.

EXPIRE is a calculation which predicts the reactivity-lifetime, instantaneous and integrated effective multiplication constants and instantaneous and integrated effective multiplication constants and instantaneous conversion ratio for heterogeneous reactors. The concentration of all the isotopes of interest from Th232 to Am243 are calculated as a function of time using the average reactor power density and a uniform flux distribution. The equations have been programmed for the IBM-704 computer and the average running time is approximately two minutes per reactor lifetime.

Release of fission products from UO2 with emphasis on fuel elements operated at higher surface temperatures and lower external pressures than those for pressurized-water systems.

An investigation is made to determine the adequacy of presently used analog circuits in solving dynamic fluid flow heat transfer equations. A mathematical analysis is made of dynamic heat transfer in pipes with zero losses, with losses proportional to pip temperature, and with heat inputs. The results of this analysis are compared with analog results by means of generalized temperature versus time graphs. The analog circuit is found to be adequate for most conditions, but sometimes requires modification when heat inputs are considered.

Abstract: The purpose of this report is to describe the problems inherent to general dielectric strength measurements, and to act as a guide in establishing a method for pulse dielectric strength measurements.

Abstract. The Equivalence Theorem of P. Lax is extended to difference schemes for initial-value problems for linear inhomogeneous PDE with linear inhomogeneous boundary values and for boundary-value problems.

In October 1959, a combination testing station developed at HAPO was reported to the Sheath committee. This testing station consisted of electronic instrumentation and mechanical scanning equipment to check coextruded fuel elements (rod and tube) for clad thickness, clad integrity, bond, and core integrity. The clad tests are performed by eddy current methods and the other are ultrasonic.

Considerable work has been done on decontamination procedures for both corrosion products and fission products. Testing of promising procedures under typical rupture conditions is an important phase of this work. The Irradiated Rupture Prototype (IRP) has been used since August in this evaluation work. This document is one of a series reporting these data.

Abstract: This technical report is concerned with the program and results of the SM-1 reactor vessel head removal and core inspection at Fort Belvoir, Virginia from the period March 7, 1969 to May 17, 1959. It covers the operating procedures in detail and records the conditions found and problems encountered in order to make a record for reference in future work of this nature. The major objective of the program, to obtain irradiation data on the SM-1 type core, has been met. The boron control rod elements were found unsatisfactory for full core life, and europium oxide elements were placed in the core for future irradiation stability data. A major problem was experienced with the cracked pressure vessel head studs. The methods developed for the removal of the broken studs are presented. The complete metallurgical study of the stud failure from stress corrosion is included as Appendix B.

A part of the development activities of the Process Equipment Development Group, Chemical Development, HLO through the year 1959 has consisted of test evaluation of some of the never products of manufacturers, design and refinement of novel units to do certain specialized jobs and development of improved components for existing plant equipment. Modification of present chemical processing methods and investigation of new basic procedures have made it necessary to utilize different and "exotic" materials, titanium, has given rise to another problem-- that of the selection of adequate and compatible bearings where the titanium is used as moving or rotating part.