This is the third quarterly report that documents a system of mass flow that can record measurements of homogeneous flow, slurries, highly corrosive fluids and multiphase fluids, additionally considering pressure drops, measuring external to the flow, ruggedness and reliability.

Technical report outlining the determination of the effective resonance integral for U238 as a function of the mass ratio for cylinders of 5/8" to 3" diameter. Also gives a linear approximation of the effective resonance integral with infinite shielding in the form of a function. [From Abstract]

The following report describes work carried out to investigate whether the Hanford IB column as designed in a previous report will decontaminate the uranium adequately from plutonium, particularly if there's any slowness in either the rate of reduction or transfer of the plutonium.

Abstract: "A series of experiments was carried out to determine the precision of the spectrochemical procedure for the isotopic analysis of uranium, especially at low uranium 235 concentrations. Standards were prepared from uranium hexafluoride which had been assayed on the mass spectrometer with a 95 per cent confidence interval of 0.5 per cent of the amount present. For a determination consisting of 9 separate measurements, the best precision obtained at normal concentration on the 95 per cent confidence interval was 0.711 +/- 0.112 per cent uranium 235 (16 per cent of the amount present)."

A systematic set of thermodynamic data for most of the known compounds of plutonium is presented. From earlier data present, it is now possible to extend the tabulation of data for the compounds of plutonium to include PuF(4), PuF(5), and PuF(6).

An accidental burst of radiation occurred at the laboratory on 1 February 1951 during remote control operation of a critical experiment. There was no personnel hazard. Normal operations were resumed within 24 hr, and the active material involved in the burst returned to service within three weeks. An unforeseen brief excursion into the prompt critical region was engendered in the act of scramming the assembly at the end of a series of measurements. This report describes the effects of the burst and analyzes the probable causes in some detail.

The oxidation of uranium metal has been studied from the standpoint of the oxygen dependence of the reaction rate in an effort to establish the mechanism. The experimental data of Perkins agree with the theoretical dependence of the oxygen pressure derived this report. This agreement supports the hypothesis that the rate-controlling step in the migration of cations in the DO2 lattice, although the observed time dependence is not necessarily in agreement with this conclusion. Experimental entropies of activation are corrected for the observed pressure dependence. No firm conclusion could be reached as to whether the rate of diffusion or adsorption is rate-controlling.

A variable-length vacuum-insulated liquid hydrogen transfer line is described. The vacuum system is semi-permanent, and segments of the line are assembled with only threaded vacuum fittings. Thermal stress calculations are presented for a statically indeterminate union coupling.

An investigation was made of the neutron and gamma flux distribution along the entire length of a withdrawn control rod in the SRE in order to determine heating, activation and dose rates produced by the streaming neutrons and gammas.