Abstract: The preliminary design is described for a small electric-power-generating plant powered by an organic moderated reactor. System and component requirements are discussed and possible design configurations and equipment are described.

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.

From abstract: The vapor pressure determination of solid ThF4 has been completed. Experiments to determine the heat of formation of ThF4 by studying the reaction of ThF4 with SiO2 are described.

Introduction - The work of the Chemical Development Group has included studies on the thermal and radiation stability of organic materials suitable for reactor coolants, the thermal and radiation stability of zirconium hydride, reactor safety devices involving chemical systems, and general analytical development.

"An investigation of the chemical effects of 1-Mev electrons on BrF3 at 25 degrees C has been carried out. Pressure measurements taken during the irradiation suggest the presence of Br2 and BrF5 as decomposition products and a fractional distillation of the irradiated liquid confirmed their presence. The extent of decomposition was determined both by fraction distillation and spectrophotometric methods. The radiation effect seemed to reach saturation when approximately 10 per cent of the BrF3 was destroyed. The exposure necessary for the decomposition products to reach a concentration of half the saturated value was calculated to be 2.7 microampere hours/cc BrF3 while the "G" value was found to be 1.5. A qualitative comparison of irradiation dosages from the Statiltron with that expected from spent fuels revealed that little decomposition of BrF3 reagent is to be expected from 1-say cooled Hanford fuel (in pile for 100 days) while in the case of 1-day cooled MTR type fuel (in pile for 12 days) a saturated effect might be realized in 1-3 hours. Since at most only 10 per cent of the BrF3 is destroyed it is concluded that BrF3, from a radiation resistance standpoint, is a suitable standpoint, is a suitable reagent for …

From abstract: A conceptual design study has been performed for a sodium cooled, graphite moderated, thermal power-breeder reactor utilizing the Thorium-Uranium 233 breeding cycle. Several aspects of the design of the system are considered but no attempt has been made to supply all the details. It appears that the design presented is feasible and will allow the production of economic power as well as full utilization of thorium resources.

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.

"A study has been made of the distribution of tracer fission products and plutonium between small samples of molten uranium and solid uranium oxide, carbine, and nitride. The distribution showed the same behavior i general for all three materials: 1. The rare earth elements, Cs, Ba, and Sr were extracted primarily into the solid scrub phase. 2. Zirconium and Nb partially concentrated in the scrub phase. 3. Plutonium, Mo, and Ru tended to remain completely in the metal phase. The distribution of activities agreed with trends predicted from the thermodynamic data. Uranium oxide appeared to be the most desirable scrub material for removing large amounts of fission products from the uranium while leaving beind the Pu. In addition the uranium metal was not severley contaminated by dissolved oxide."

"An experiment to determine the effect of reactor irradiation on the thermal conductivity of uranium-impregnated graphite at elevated temperatures as described. The results show a decrease in the thermal conductivity saturating at [approximately] 60 percent at a temperature of 700 degrees C; at [approximately] 50 percent at a temperature of 1000 degrees C; and at [approximately] 25 percent at a temperature of 1300 degrees C. It was found that after irradiation at a given temperature, exposure at a higher temperature resulted in an increase in the thermal conductivity. The converse was also observed. Within the precision of measurement there was no difference in effed between temperature changes produced by varying the fission rate in the samples and changes produced by varying the power in an external heater."

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: This report presents the results of plant optimization studies and cost estimates of the reference design for a natural uranium, graphite moderated, gas-cooled reactor and power plant which was described in NAA-SR-1833.

"General Chemistry investigations reported herein includes: (1) the Organic Coolant-Moderator Program, (2) investigations on zirconium hydride, and (3) analytical chemistry."

Abstract: The data presented herein, in the form of graphs, can be used to obtain the value of this energy.

Introduction: The description of the Organic Moderated Reactor Experiment, (OMRE), its location, its safety system, and operative procedures have been previously detailed. The present report, although dealing with the subject of OMRE safety, has the more detailed intent of (1) determining the behavior of the OMRE under extremely unlikely sets of conditions; and (2) providing additional design information in the areas of reactivity coefficients, burnout heat flux, and reactor control.

"Heat production resulting from the absorption of gamma ray photons in thermal shields and the leakage of neutrons and photons from ferritic thermal shields are investigated. The gamma rays considered arise from three types of reactor radiation -- thermal neutrons, fast neutrons, and core and reflector gammas. The energy spectra of the fast neutron leakage and absorption have been investigated in some detail because of the significant contribution of fast neutrons to the heating of the concrete biological shield."

Introduction: The purpose of this experiment was to demonstrate that a liquid metal heat transfer system could be built and operated at very high temperatures.

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

"A method for solving multi-group reactor equations which arise in the diffusion approximation is outlined. Considerable work has been done on this problem at KAPL and ORNL. Their approach is to replace the differential equations by difference equations. Complications arise in this method where more than one slowing down medium is present since the fluxes are discontinuous at the interfaces. The primary purpose of this article is to develop an exact integral expression for the neutron flux which automatically satisfies the boundary conditions. An iterative method for obtaining the fluxes and critical neutron multiplication ratio based upon the above-mentioned integral expression is given. The only approximation used in obtaining the fluxes, in addition to the use of multi-group diffusion theory as the basic model, is the use of numerical integration to evaluate the analytic expression. The equations for a two region, two group spherical reactor are given in a form suitable for machine programing. The extension to more than two regions is also considered.

From abstract: The response of the reactor to forced oscillations has been investigated with the pile oscillator technique and the data are presently being analyzed.

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.

Abstract: The fast and thermal neutron leakage from the 30 megawatt SGR-P4 reactor has been studied by three independent methods.

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.

Report describing reactor components, operational characteristics, and operating instructions for the Model L-3 research reactor.

Report describing technical progress on the design and construction of an Organic Moderated Reactor Experiment (OMRE), to be operated at the National Reactor Testing Station in Arco, Idaho. "This is the second report of the series, and covers the period from August 1, 1956 through October 31, 1956" (p. 3).