This report summarizes the results and conclusions of a study made to evaluate the merits of using zirconium hydride as a solid moderator in an integral boiling water-nuclear superheat reactor of the pressure vessel type.

Report discussing two trial runs for a grannular resistance processing furnace, in which the goal was to produce high purity graphite. These tests were a continuation of a series of trial runs that had previously yielded inconsistent results.

Abstract: "A phase diagram for the uranium-cobalt system has been constructed, based on thermal, microscopic, X-ray and chemical data. The results indicate the existence of three compounds and two eutectics, one of which shows a lowering of the melting point of uranium by approximately 400 C."

Technical report describing that voids were measured in a ½-inch by 1-3/4-inch channel with the S-1 insert (B(0)/B(1) = 0.4, L(0) = 0.1 inch), at 2 inches ahead of the insert (position A), ½-inch past the insert (position B), 5 inches past (position C), and 12 inches past (position D). The conditions were: P – 1000 psia, G = 1.00 x 10(6) lb/h-ft(2), and x = 18.8 percent. Average void and void distribution at position A are the same as for flow in a straight channel. Void distribution at position B shows that the stagnation region downstream of the inserts contains a high fraction of voids. Average void and void distribution at positions C and d show that the two-phase mixture becomes strongly mixed (homogenized) as a result of passing through he contraction-expansion inserts. Distribution at position D approaches the distribution at position A; i.e., the straight channel distribution.

Recent measurements on the long counter efficiency in which comparisons were made with the (n, p) scattering cross section, additional variations in efficiency were found which varied slowly with neutron energy but were still correlated with the total neutron cross section of carbon. Because of these variations in efficiency there are errors in the fission cross sections reported in LA-1714. Corrections to these data have been given here.

A report about the fabrication of dummy fuel-pls assemblies which are to be used in the engineering test loop at the MTR.

A report about the design and construction of equipment for thermal-conductivity measurements of irradiated encapsulated uranium. Metallographic techniques used to confirm solubility limits of uranium in thorium, previously determined by electrical resistivity and X-ray data, have been unsuccessful.

A report about aluminum-clad fuel elements, fuel-element development, zirconium uranium alloys, corrosion of zirconium, and reactor material development.

A report intended to correlate the RA and RC Column uranium equilibrium data presented in the reports cited in the introduction.

Equations are developed for the computation of MPC's for radioisotopes assuming the excretion or retention to follow a power law rather than an exponential law. Computations are made for four isotopes on which some human data are available. Uncertainties in the initial data due to the use of intravenous injection to obtain the primary data, the definition of retention and the effects of age and diet are discussed.

Studies are described of the percutaneous absorption and gastrointestinal absorption in the rat of ruthenium administered in the form of "insoluble particulates." Results are also reported on the gastrointestinal holdup of these particulates.

From Object and Scope of This Paper: "This paper describes the apparatus and procedures used at the National Bureau of Standards for the measurement of d-c resistance when an accuracy of a few parts in a million is required. The object will be to explain procedures in detail and as simply as possible, with a minimum reference to theory."

From Introduction: "The present paper contains detailed descriptions of the methods used in calculating both the elastic constants and the statistical parameters. These detailed descriptions have been included for two reasons: (1) To leave no doubt as to the exact procedure, and (2) to act as a guide to other workers who might wish to make similar determinations."

From Introduction: "The purpose of this paper is to present information on materials that are used from 0 degrees C up in thermocouples intended primarily as immersed temperature sensors, and to give so far as is practical properties of these materials that might affect their use in temperature measurement."

Abstract; The heat exchanger and steam generator for the U.S. Atomic Energy Commission Sodium Components Project will be constructed entirely of type 316 stainless steel. Because of the susceptibility of this alloy to stress corrosion cracking, it is proposed to clad all areas of the steam generator with Inconel where the stainless steel will be exposed to water and steam. This report includes a discussion of the work by numerous investigators that justify the selection of Inconel for this service. A discussion of Inconel type welding alloys is also included.

The objective of the Accurate Nuclear Fuel Burnup Analyses program is to develop more accurate methods for burnup analysis for general use than the current method of analysis of Ca-137 or Sr-90. The program will require from three to five years of effort.

The coefficient of linear expansion of alpha plutonium has been determined for the range -180 to +100 degree C by the silicon-tube and dial-indicator method. The value of the expansion coefficient is reported as [formula]. Included are a detailed description of the apparatus and a discussion of the method.

A tentative nickel-plutonium constitutional diagram was based on data obtained by thermal analysis, metallography, and x-ray-diffraction techniques. The systema is a complex one with the following important features. Nickel is soluble in epsilon plutonium, extending the epsilon field to 4.3 at.% nickel at 465 deg C. Nickel and plutonium form six intermetallic compounds, PuNi, EnNi/sub 2/, PuNi/sub 3/, PuNi/sub 4/, PuNi/sub 5/, and PuNi/sub 9/. The compound PuNi/ sub 5/ forms congruently from the melt at approximately l300 deg C, whereas the other compounds form peritectoidally. The extended epsilon field terminates in a eutectoid reaction at 415 deg C and l.5 at.% nickel. Epsilon plutonium and the compound PuNi form a eutectic system at 465 deg C with a eutectic composition of l2.5 at,% nickel. Nickel and the compound PuNi/sub 9/ form a eutectic system at l2l0 deg C with a eutectic composition of 92 at.% nickel. Plutonium forms a limited solid solution with nickel.

Technical report covering chemistry of source, fissionable, and structural elements, nuclear chemistry, radio-organic chemistry, chemistry of separations processes, chemical physics, radiation chemistry, and instrumentation at the Oak Ridge National Laboratory for the period ending September 30, 1950. [From Abstract]

Quarterly report describing progress on the EVESR Nuclear Superheat Fuel Development Project.

Report documenting the Halogen Collector Test program, which was undertaken to provide "methods of removing trace quantities of radioactive iodine from an air stream" (p. 1). The report includes designs of the program and the test facility, test results, analysis of these results, and encountered problems. Appendices begin on page 38.

From introduction: "This report provides background information regarding the study results presented in the first volume of this report and provides information resulting from the studies made on the gas cooled reactor concept."

Study of factors, such as the average particle size and particle-size distribution, which affect the fluidization properties of uranium trioxide powders.

Report reviewing the theoretical methods of optical pyrometry and the application of these methods at the National Bureau of Standards in realizing, maintaining and distributing the International Practical Temperature Scale above 1063 ºC is presented. In the theoretical presentation, the concepts of effective and mean effective wavelengths are introduced, and various equations relating these parameters to each other and other physical quantities are derived. The methods presentation discusses important features of precision visual optical pyrometers, experimental procedures, and results of primary and secondary calibrations of optical pyrometers.