Abstract: This document is a survey analysis of soil samples from Los Alamos, Pueblo, Bayo, and Mortandad canyons to determine the presence and activities of radioactive contaminants. Also included are the results of analyses of a few samples of grass and of surface water. This survey covers the period from spring 1953 to spring 1955.

The perturbation theory for material replacement experiments is given through second order thus permitting corrections for sample size. Computed flux and adjoint distribution functions are tabulated for the Lady Godiva assembly enabling the observed danger coefficients for U-238 and U-235 to be compared with corresponding predicted values. Consistency of this data is checked by its use in three independent combinations each yielding for the effective fraction of delayed neutrons from fast fission the value L841=0.0068 * 0.0002. Estimation of the reactivity contributions associated with inelastic scattering give the following connection between central danger coefficient ratios and [(%1>~-q~ ratios for the Topsy assembly (oralloy core + 81/2”tuballoy reflector), AK$U-233) A&(U-235) AKO(PU-239) AKJu-235) = 1.71= 1.93 = 1.78. Evaluation of transport cross sections by means of replacement measurements in Godiva is illustrated for the several elements carbon, copper, and gold, the values relative to ~!&(OY) = 1 being ~fi(c) = ().43 f 0.02, ~(CU) = 6.5!5 * 0.02} ~ti(Au) = 0.91 f 0.02.

A device has been designed which will support small spheres and cylinders in a vacuum system during a plating operation. While supporting the object to be plated, the device automatically shifts the position of the supports so that the coating is evenly distributed. This report describes the mechanism by which this motion is achieved.

This technical report summarizes the work which has been done to date on the preparation of magnesium hydride and the attempted preparation of beryllium hydride. Although pure beryllium hydride has not yet been made, the work is continuing, and this report indicates which phases are thought to be worth further work.

Abstract: An appraisal is made of the radiologic hazard created by a 1000-ft. high air burst of a nominal sized nuclear bomb. Three sets of graphs are included which show the relations between dose rate (milliroentgens per hour), time post-shot, and distance from Ground Zero for a soil having given constituents. Estimates are given for fall-out activity (gamma) for distances up to about 200 miles from Ground Zero immediately after fall-out. It is pointed out that the radiologic hazard due to fall-out in the example cited is insignificant; further, that the radiologic hazard from similar nuclear bombs bursting at different heights above the ground will vary to a considerable extent.

The transition region between short, but controlled, pile periods and uncontrolled, highly-supercritical conditions has been investigated with an unreflected, spherical uranium assembly (Godiva). This study was undertaken because knowledge of the behavior of supercritical systems is important in evaluation of reactor hazards and also the hazards of less standard operations involving possibly critical quantities of active material.

In this report, the stability of a pinched fluid is studied theoretically, under the combined influence of a longitudinal magnetic field and conducting exterior shell. Conditions allowing complete stability are found.

Data on critical configurations of fissionable metals are summarized in a form emphasizing the influence of conditions commonly of concern in nuclear safety questions.