Introduction: This is the fourth report in a series of reports dealing in particular with a reactor safety device of a double diaphragm type.

Abstract: A device to detect the presence of hydrogen in sodium has been developed. Such a device, installed in a sodium heated steam generator, would signal the presence of water in the sodium resulting from a leak in the sodium-water barrier.

Abstract: This report, intended as a working document, contains analytic representations and analog models of the Hallam Nuclear Power Facility as used in studies of the Control and Protection Systems.

Abstract: Presented herein is the preliminary design of a natural uranium, graphite moderated, CO2-cooled reactor and power plant similar to, but larger than, the British Calder Hall plant, with a net electrical output of 130 MWE.

Abstract: A calculational method is presented which may be used to determine fast and thermal neutron flux distributions at deep neutron penetrations in hydrogenous shields.

Abstract: Irradiated fuel elements from the Organic Moderated Reactor Experiment (OMRE) first core loading have been examined and evaluated to determine: (1) the stability of the floating plate fuel element design, (2) the stability of the stainless steel clad UO2 - stainless steel cermet core fuel plates under irradiation and exposure to the organic coolant, (3) the extent and nature of deposits on the fuel element services, and (4) the distribution of burnup in the fuel elements.

Abstract: This report outlines the general techniques developed for replacement of PRE in-cell equipment or equipment components.

Abstract: A magnetic-jack control-safety rod is under development for the 45.5 thermal megawatt Organic Moderated Reactor. The rod is "unitized," i.e., the poison element, drive, position indicator, and shock absorber are contained in a compact assembly which is inserted in a regular fuel channel opening in the core. Tests to develop components capable of operating under these conditions are described and results are reported.

Abstract: The measurement and calculation of the reactivity absorbed by Xe135 as functions of time after shutdown for the SRE are described.

Abstract: This report presents a description of the Organic Moderated Reactor Experiment (OMRE), of the hazards associated with this experiment, and all of the safeguards taken to ensure the safety of the operating personnel and the population of the surrounding area.

Abstract: An intuitive approach to the understanding of crystal structures is presented in terms of the concept of the closest packing of spheres.

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: The design and application of two computers for the HNPF protective system is discussed.

Abstract: In the present study, the variation of moderator composition was postulated to be effected by the inclusion of varying amounts of beryllium oxide in the graphite of an SGR.

Abstract: This report describes the features of several systems which were rejected as inadequate, and the evaluation of a design leading to the construction of a prototype cask and its associated equipment.

Abstract: A loop has been constructed to study the removal of water and highly volatile materials from Organic Moderated Reactor coolant by vacuum degasification. An analysis of the process was made to determine the most important parameters for study during the experimental program.

Abstract: Accurate measurement of OMRE fuel-element surface temperatures is important for evaluation of the performance of organic compound as moderator and coolant materials in nuclear reactors; a mixture of polyphenyls has been used in reactor operation to-date.

Abstract: A generalized equation of state developed by Gouq-Jen Su and Chien-Hou Chang is used for predicting P-V-T behavior of BF3 at high gas densities.

Abstract: An alluminum-clad low-enrichment, uranium-alloy fuel element of flat plate configuration has been proposed for the Organic Moderated Reactor (OMR).

Abstract: The influence of plutonium on the nuclear characteristics of organic moderated cores is studied.

Introduction: This document describes the results of a six-week conceptual design study of an organic moderated and cooled reactor (OMCR) power plant adapted to a Class T-7 tanker.

"An intuitive approach to the understanding of crystal structures is presented in terms of the concept of the closest packing of spheres. The qualitative features of the concept are sorted out and correlated by successively treating single, double, triple, and multiple layered arrays of closest packed spheres" (p. ix).

The design of a waste-gas treatment system for organic moderated reactors requires a knowledge of reactor waste-gas composition, generation rate, and radioactivity. To obtain data on these variables a continuous stream analyzer was constructed to analyze the waste gas from the Organic Moderated Reactor Experiment (OMRE).

Abstract: A conceptual reference design of a 318 Mw(e) Graphite Moderated Boiling and Superheating Reactor (GBSR) is described.