Abstract: Testing of the Natural Circulation Steam Generator has been conducted with the Sodium Reactor Experiment. A necessary modification of the original feed-water control system was utilized.

Abstract: "Most of the Nuclear Merchant Ship Reactor (NMSR) shield design work performed by The Babcock & Wilcox Company (B&W) is summarized. Primary and secondary shield results are presented, consistent with contractual requirements and designated design criteria. Methods of calculation and basic parameters are shown" (p. 1).

From abstract: Liquid alkali metals were circulated in a series of structural alloy loops under reactor radiation at high temperature. The first of these loops was a lithium-stainless steel (type 316) system, and the remainder were sodium-Inconel. No effect of radiation other than radioactivation was found. Mass transfer and metallurgical processes attributable to the operating temperatures were observed."

From major objective: The over-all aim of the study has been to obtain a thorough geologic picture of the Chattanooga shale in the area under consideration, with emphasis upon stratigraphic relationships and associated special problems from which, in turn, implications may be obtained as to the origin and age of the formation and possibly the source of the uranium. The study has not been aimed primarily at exploration for uranium and its economic aspects.

A report which compares the creep properties of 15 percent cold-worked zircaloy-2 and of annealed zircaloy-2 is being made.

From abstract: A gamma-radiation telemetering system was utilized by Civil Effects Test Group personnel to measure fallout levels at the Nevada Test Site from the vicinity of Ground Zero out to, and including, an area bounded by Reno, Nevada; Salt Lake City, Utah; Kingman, Arizona; and Barstow, California.

Design analysis of a prepackaged nuclear power plant.

Design analysis of a prepackaged nuclear power plant.

From introduction: "The purpose of the report is to set forth the development philosophy, objectives and expected results of the AEC-GE Nuclear Superheat Project."

Report describing the Hanford Plutonium Recycle Test Reactor (PRTR), its building, safety procedures, site, operations, and analyses of its safety features.

From objective: "The objective of this work was to design, develop, assemble, and test and automatic analyzing monitor for recording the prominent isotopes in reactor effluent cooling water."

Report presenting the design, research programs, and design objectives for an Organic-Cooled Reactor.

Production of new surface area by fracturing of rock behind an explosive-initiated high amplitude wave is probably an important mechanism for energy absorption in the region near n explosion in rock. Explosive-initiated high amplitude pulses in cylinders of three different rocks and two concretes were studied to determine the pulse amplitude need to damage the cylinders. An average high amplitude wave velocity of half the elastic wave velocity was observed in a porous limestone. Elastic theory is not expected to apply to a wave fracturing a rock. Rapid decreases in original free surface velocity of the greywacke rock which was most thoroughly tested indicate that this rock sustained tensile stresses about a hundred times greater than its probably tensile strength for times a long as fifty microseconds.

This is the fifty-fourth progress report of the Laboratory for Nuclear Science at the Massachusetts Institute of Technology. Progress reported covers the period for Physics and Chemistry through April 30,1959. Progress is reported on: (1) Chemistry of the fission elements group, (2) Nuclear chemistry (inorganic) group, (3) Nuclear chemistry (organic) group, (4) Cosmic ray group, (5) High energy accelerator physics group, (6) Bubble chamber group, (7) Liner acceleratory group, (8) Rockefeller generator group, (9) ONR generator group, (8) Radioactivity group, (9) Cyclotron group, (10) Theoretical group, (11) Personnel listing.

The need for thermal and fast neutron fluxes in the range of 1 to 5 x l0/ sup 15/ neutrons/cm/sup 2/(sec) for the production of heavy elements such as Cf/ sup 252/ and other special isotopes and for improving the quality of beam experiments, reactor materials testing work, and solid state research has led to plans for the construction of three ultra high flux research reactors. The designs of these and other high flux research reactors are based on the general technology of enriched tank-type reactors; however, they utilize the principle of separate fuel and moderator regions to achieve flux peaking in these regions. Thus, proposed designs take the form of an annular fuel region with internal and external moderating regions or an under moderated core with an external moderator or reflector. In such arrangements, the thermal flux peaks in the moderating regions and the fast flux peaks in the fuel region, which results in maximum fast and thermal fluxes per unit of power. Since most of the moderation of fast neutrons takes place outside of the fuel region, the thermal flux peaking depends on the number of fast neutrons leaking from the reactor core, which in turn depends on …

Progress reports from four divisions are included: (1) Division of Biophysics; (2) Division of Clinical Investigation; (3) Division of Nucleoprotein Chemistry; and (4) Radiochemistry Section.