Report documenting the progress of the Army Gas-Cooled Reactor Systems Program to develop a mobile nuclear power plant for military field operation.

Recent (HCR) Horizonal Control Rod operating problems at the K Reactors, caused primarily by graphite stack distortion, have stimulated several designs of HCR`s capable of operating under adverse conditions. One such design is an aluminum HCR, not completely dissimilar to the present HCR`s, conceived by the Research and Engineering Operation of I.P.D. The successful use of aluminum as a structural material is strongly dependent upon the operating temperature of the aluminum. This study was conducted to determine anticipated operating temperatures of the HCR during reactor operation at the present K Reactor conditions.

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The initial 30-Mw SRE Core III loading will contain a total of 33 fuel elements. Of these, the central 7 fuel elements are test elements and the remaining 26 are driver elements; 4 of the 7 test elements are designated as standard test elements. These elements are identical to the driver elements with the exception of the active fuel length. The remaining 3 test elements are designated as special test elements and incorporate fuel rods of smaller diameter and increased enrichment to obtain higher burnup rates, greater specific power, and higher fuel temperatures. Geometry design data for the various elements considered in the analysis was obtained from Dwg. No. 650 deg F, the mixed-mean coolant outlet temperature for the core at 1200 deg F ( plus or minus 15 deg F), the maximum average temperature on the cladding at 1275 deg F, and the maximum fuel temperature in the range of 2000 to 2100 deg F. The thermal performance of the fuel elements was analyzed with the SORTD code and the Heating code. The results of the analysis are presented in tabular form. Axial temperature profiles are also presented for representative fuel elements. The core outlet coolant mixed-mean temperature was …

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The outgassing characteristics of specimens of the EGCR moderator graphite stock were determined in vacuo to a maximum temperature of 1000 deg C using external resistance heating and to 1800 deg C by induction heating. The specimens examined were cut from several locations in two of the 18-in. x 18-in. x 20-ft graphite bars which had been prepared under fabrication conditions comparable to those used for the graphite columns present in the Experimental Gas- Cooled Reactor. Data are given which show the effect of the position of sampling of the bars on the density of the graphite. The volume and composition of desorbates obtained at 300, 600, and 1000 deg C as a function of specimen size and position of specimen within the bars also are given. The volume-time relationships at 300 and 600 deg C can be expressed satisfactorily by v = A log t + B over extended intervals of time. A linear relationship prevails at 1000 deg C only after heating for longer than approximates 800 min. The volume and composition of the desorbates obtained at 1000, 1400, and 1800 deg C using induction heating are tabulated. (auth)

This report details progress in an intensive investigation which was launched to determine the basic mechanisms leading to gross loss of UO{sub 2} fuel upon thermal cycling of UO{sub 2}-W cermets and to suggest means of overcoming this serious operational problem. (This problem was recently uncovered at both Lewis Research Center and at Hanford). More than 40 separate experiments were conducted in four high temperature furnaces, at temperatures to 2600 C, pressures from 10{sup {minus}5} mm vacuum to 1000 psi, atmospheres including wet, pure and tank H{sub 2}-Ar mixtures, N{sub 2}, and He, and cycle periods from 30 seconds to 15 hours. Specimens examined included two types of NASA-fabricated plates, three types of Hanford high energy impacted discs, and several other materials used for single experiment evaluation.

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Four years of intermittent development has culminated in the successful test drilling on-reactor, of one step plug hole. Since 1960, several different drive units and many diamond, carbide, and tool steel cutting heads were tried unsuccessfully in attempts to bore a stepped hole in a mockup of B, D, P side shielding. Success was finally achieved in 1963 using a standard horizontal boring mill and tool steel cutters. With slight modifications, this same equipment was successfully used in an on-reactor test drilling at F Reactor in December of that year. The on-reactor test revealed the need for improvements in the equipment. Chip flow was inadequate and appeared to be caused by poor air flow in the core receiver. Cast iron cutting technology used on the mockup did not work on-reactor and had to be revised on the spot. The graphite did not break up into chunks as desired and had to be manually removed. None of the steel cores were more radioactive than 50 mr/hour at approximately 2 inches, but the cast iron core read 300 mr/hour at 10 feet. It had to be handled very quickly. The dose rate for handling the graphite was 400 mr/hour. It, too, was …

A survey was made of the literature which was published on the reduction of plutonium compounds to plutonium metal between 1950 and April 1963. This report is a summary of the information which was gathered during the survey. (auth)

This report discusses comments received on the previous report on internal graphite moderator forces (HW-79120); sleeve test channel inspection; and BDF reactor distortion.

The irradiation-induced creep of graphite is being investigated in experiments that consist of loading parabolically shaped cantilever beams at the free end and measuring the resulting deflections with time. A series of stress analyses was made to verify the applicability of the elementary strength-of- materials approach for obtaining relations between stress and creep strain from the load-deflection data. The results of the analyses, which included a theory- of-elasticity solution, an evaluation of the effect of shear, and a bending analysis using an actual stress-strain diagram for graphite, show that an elementary strength-of-materials approach is adequate to predict the initial or elastic stresses. Preliminary results from the in-pile experiments indicate that the creep strains are linear with stress; thus the initially linear bending stress distribution given by the elementary theory remains unchanged during creep. (auth)

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Anodization of the SNAP reflector for the 125 kw, 1300 deg F design point results in a reflector temperature of 760 deg F. By comparison the reflector temperature for the 53 kw, 1200 deg F design point with no anodization was 795 deg F. (auth)

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As specified in PITA IP-26-I, a test has been conducted at DR reactor to find the amount of nonpressure sensitive air entering the reactor, and gain other information on the reactor gas system. The purpose of this document is to place in effect interim normal gas purity limits and define assuredly positive gas system pressure based on the results of this test.

This report discusses testing conducted to establish an interim normal limit for nitrogen concentration in the reactor gas; obtained information to be used in defining assuredly positive gas system pressure; and obtain other useful information on the reactor gas system, such as total apparent system volume, accuracy of the gas activity meter at low nitrogen cencentrations, etc.