Introduction: Seldom does the actual arrangement of control elements in a nuclear reactor confers to the ideal and convenient mathematical array. In order to achieve shim control. safety and regulation, it is desirable to design with rods of different sizes and materials. With given fuel element arrangement, typically in square or hexagonal lattice spacing, there will be rods located at different distances form the center of the core and from each other. As the reactor operates, absorbers will be withdrawn, leaving further asymmetries in the location of those remaining. It is the purpose of this report to develop in detail a two-group diffusion theory with as complete generality as possible. The method is as yet restricted to the unreflected core, or to the reflected core by use of reflector savings and bare equivalent geometries.

Abstract: This monthly progress report covers the activities of the Army Gas-Cooled Reactor System Program for April 1959. The program includes a water-moderated heterogeneous reactor (Gas-Cooled Reactor Experiment I), a graphite-moderated homogeneous reactor (Gas-Cooled Reactor Experiment II), a mobile gas-cooled reactor (ML-1), and the coordination of the Gas Turbine Test Facility. [It reports] the progress of each project, the associated tests and data evaluation, the applicable design criteria, and the fabrication of reactor components" (p. 1).

Summary: Prototype testing of the safety and control rod drives indicated that both units functioned properly. No major problems were encountered during testing. Seal leakage data collected indicated that the seal units were performing satisfactorily. Scram times during both cold and hot testing were excellent and actually better than expected.

"This report presents the conceptual design of a 75 MWe prototype Mixed Spectrum Superheater power plant. The scope of the work has emphasized primarily the design, performance, and cost information on the nuclear portion of the plant. The research and development programs required to insure plant feasibility are also present."--Intro.

Abstract: Progress is reported on research and development tasks under the Program Plan for Engineering Support and Development of Army Pressurized Water Reactor Power Plants, Contract AT(30-1)-2639, during the six months' period October 1, 1061 to March 31, 1962.

This technical report discusses an infrared study of AlH3-2N(CH3)3 while the compound was in its gas phase. This investigation was then extended to include the Raman spectrum observed in liquid trimethylamine.

Abstract: "Production of [rho]'s and [omega]'s in [pi]- + p and p + [letter p with a bar over it] interactions is discussed. The [rho] is presumably a J = 1-, 1 = 1 state and thus can decay into 2[pi]'s via a strong coupling. The [omega] is probably J = 1-, 1 = 0 which can also decay into 2[pi]'s via electromagnetic coupling. A theoretical description of this situation is presented in terms of coupled time-dependent Schroedinger equations which mix [rho] and [omega] states that are assumed to be isotopically pure at the time of production. The interference between the two resonances was found to have the effect of extending the 2[pi] spectrum toward the [omega] mass."

The objective of Project 30.7 was to investigate the predicted behavior of German underground personnel shelters, equipment, and certain instrumentation. Data obtained will be used for evaluation and improvement of present design criteria.

Abstract: The most adverse power distribution and power peaking factors have been developed for Type 3 replacement cores for SM-1, SM-1A, and PM-2A. Also included is the 37 element Type 3 core for SM-1, which is known as SM-1 Core III and is a prototype of a Type 3 core for PM-2A. The power distributions were compared with measured distributions obtained on type 3 fuel elements in SM-1, SM-1A and PM-2A core configurations. Using the measured data as a standard, correction factors were obtained and applied to the analytical predictions of the most adverse power distribution.

From introduction: The broad objectives of the Survey's program are to provide the basic geologic and geophysical information needed to define the pre- and post-shot geologic and physical properties of salt and other rocks affected by the explosion. To provide geologic and hydrologic information on the pre- and post-shot hydrologic conditions at the Gnome site and surrounding region.

Technical report. From Abstract : "The silver-1,10-phenanthroline system has been studied and the stability constants determined for the 1:1 and 2:1 complexes using the silver electrode. This known system was then used to study the complexes of 1,10-phenanthroline with other metals. The log βn values found for the over-all stoichiometric stability constants are as follows: Ag, 5.02, 12.07; Mn, 3.88, 7.04, 10.11; Cd, 5.93, 10.52, 14.30; Zn, 6.83, 12.05, 16.92. The stoichiometric stability constants determined for copper are log k2 = 6.42 and log k2k3 = 11.05."

Report comparing the fuel cycle costs and temperature coefficients of reactivity for PuO2-UO2 fuel in multiple megawatt reactors.

From abstract: A high speed motion picture study was conducted of boiling flow in a vertical, rectangular channel at atmospheric pressure. Three different visual flow regimes were defined and described.

" A reliable, efficient and economical method is needed to remove radioactive halogens such as iodine and bromine and particulates from air in many atomic energy installations. One method we have developed which is particularly suited to reactor containment vessels or other large confined areas is foam containment. In this method an ether lauryl sulfate foam containing an iodine reactant is generated, rapidly filling the entire containment volume. This provides a tremendous surface area to which the encapsulated gases and particles can diffuse and be removed."

Technical report. From Introduction : "The nuclear volume dependent isotope shift of optical spectral lines has long been a very useful means for studying the changes in the nuclear size or shape for different isotopes of heavy elements."

From abstract: The Madelung constant and the inverse twelfth power repulsion factor have been calculated for the wurtzite structure for wide ranges of the crystal parameters and u.

From abstract: A development program was initiated to design, fabricate and test an absorber column with a 10 to 12 year lifetime, for use in the proposed LSGR.

Abstract: A limited study of the compound U₃Si₂ has been made in reference to its use as a prospective nuclear fuel in sodium cooled reactors.