Neutron density at the end of the slug is increased appreciably and therefore the heat production in the end of the slug is also increased. The end result is increased heat flow into the cap with correspondingly higher temperatures. The combined results and conclusions of documents CP-1580, CP-1989, and CP-2871 afford a means of calculating the aluminum end cap temperatures with consideration being give to the above mentioned {open_quotes}Wilkins effect,{close_quotes} i.e., that the heat production near the end of a slug with an aluminum end cap is greater than the heat production at the middle (axially) of a slug. The maximum temperature in the aluminum end cap is calculated to be about 278{degrees}F. for the {open_quotes}G{close_quotes} Pile. This temperature occurs at the center of the maximum performance process tube.

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This report is intended to be a description of current work being done by the Physics Unit at the Hanford Atomic Products Operation. The work is concerned mainly with the study of graphite-moderated natural uranium reactors for the production of plutonium on a large scale. In addition, varied physics problems associated with the operation of an industrial atomic plant are occasionally dealt with. The report is divided into four sections; lattice physics; nuclear physics; irradiation physics; and plant physics.

To one whose responsibility it is to make evaluations of the degree of hazard existing in the radiation field of a nuclear accelerator or a nuclear reactor, the valid estimate of the contribution of neutrons to such a field is of considerable importance. The degree of difficulty of such a measurement depends strongly upon the information desired - whether (1) simply the presence of 'slow' and 'fast' neutrons in significant numbers is in question, or (2) a measure of flux densities within known energy intervals is required, or (3) a direct estimate of the specific rate of energy absorption due to neutron-produced effects in a given medium is desired. The importance of securing trustworthy estimates of the neutron field can be appreciated by recalling that the biological damage due to a given amount of ionization produced in biological tissue by effects due to neutrons is estimated to be several times the damage due to a similar amount of ionization produced by X-rays or gamma rays. This 'relative biological effectiveness' must be evaluated by carefully controlled animal experiments. Its value appears to range from about 2.5 for slow neutrons to abount 10 for fast and high energy neutrons. Of course the …

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The nonmetallic inclusions in both as-reduced and fabricated dingot U were studied for comparison with those in ingot U. Special attention was paid to the hydride for the purpose of determining the amount and distribution in the various types of U. The types and distribution of other inclusions were also studied. It wss found tbat the dingot U was of a higher quality than ingot U and was comparable to as-reduced derby U on the basis of over-all inclusion count. The H content in dingot U, however, was found to be appreciably higher than in either ingot or derby U. (auth)