Tests made prior to beginning operation of the 100 Areas showed that the cooling water had a tendency to deposit a film upon the slug and tubs surfaces. This film would manifest itself as an increase in the pressure drop through the tubes and its most serious affect would be the resultant decrease in the slug to water host transfer coefficient which would increase the slug surface temperature, causing greatly accelerated corrosion rates. It was thus proposed to study film formation an a production test. This report discusses this test.

This technical progress report details 100 Area activities for the time period of August 13 through August 19, 1946.

It was agreed during a meeting on July 10, 1945, investigation should be made to determine how fast and in what fashion the temperature of the effluent water from the 100 Areas is dissipated in the Columbia River. A preliminary report on these investigation was issued March 1, 1946: it discussed the testing techniques developed and the results of a survey made at the 100-B Area. Following a review of the data and tentative conclusions resented therein, it was agreed to extend the survey using similar technique: to the D and F Areas, and to determine if the tentative conclusions were substantiated.

The weekly progress for D and F piles is given. Status of the test to determine the cause of white deposits on the horizontal control rods of the F pile is given. Also discussed are studies of process water control and pressure drop, corrosion, and graphite expansion. Test results indicate that graphite expansion has not seriously limited discharge of process tubes.

This report details 100 Area reactor operation for the time period of August 6 through August 12, 1946.

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A theorem is derived which is useful in the analysis of neutron problems in which all neutrons have the same velocity. It is applied to determine extrapolated end-points, the asymptotic amplitude from a point source, and the neutron density at the surface of a medium. Formulas for the effect of finite tampers are derived by its aid, and their accuracy is discussed.

Methods are developed for estimating the effect on a critical assembly of fabricating it as a lattice rather than in the more simply interpreted homogeneous manner. An idealized case is discussed supposing an infinite medium in which fission, elastic scattering and absorption can occur, neutrons of only one velocity present, and the neutron m.f.p. independent of position and equal to unity with the unit of length use. (auth)

Thermal reactors that have a significant fraction of fissioning occurring just above thermal energies are studied. First, the thermal neutron diffusion equation is corrected for fast fission effects. The resulting diffusion equation is shown to be equivalent to the Fermi Age equation corresponding to the same physical assumptions. Next, the one delayed neutron group kinetic equations for the corrected thermal flux are given, and the life time of the thermal neutron is corrected by the average slowing down time. (auth)

The magnitude and distribution of the fission rate per unit area produced by three energy groups of moderated neutrons reflected from a water tamper into one side of an infinite slab of active material is calculated approximately in section II. This rate is directly proportional to the current density of fast neutrons from the active material incident on the water tamper. The critical slab thickness is obtained in section III by solving an inhomogeneous transport integral equation for the fast-neutron current density into the tamper. Extensive use is made of the formulae derived in The Mathematical Development of the End-Point Method by Frankel and Goldberg. In section IV slight alterations in the theory outlined in sections II and III were made so that one could approximately compute the critical radius of a water-tamper sphere of active material. The derived formulae were applied to calculate the critical dimensions of water-tamped slabs and spheres of solid UF{sub 6} leaving various (25) isotope enrichment fractions.

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This report, from the Hanford Plant, May 22, 1956, describes the need, design, and testing plans for an agitator to aid in dissolution.

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