The following report examines the fission counter, fission plates and activation results of the neutron energy distribution in the center of the Los Alamos plutonium reactor.

The operation of the Fast Reactor is considered in terms of normal equilibrium conditions and normal shut-down. The proposed loading, control rod adjustment and subsequent "floating" operation are discussed. Safety devices and interlocks are described. Temperature and reactivity changes are examined with respect to various system failures, phase changes, and "flashing" of the reactor. Slow changes due to faulty slug cooling are also considered. The calculations were initially based upon 10 kw operation. Performance tests of the mercury system now indicate that 20-kw operation may be feasible.

This report records two samples of Xe-135 that have been isolated with activities sufficient for the measurement of the cross section of Xe by the velocity spectrometer technique.

From abstract: "Critical assembly tests have been made on the Pajarito Universal Machine to determine the safety limits of handstacking cubes of 95% U-235 in spherical geometries preparatory to making critical assemblies of U-235 in an "infinite" tuballoy tamper. The U-235 cubes were stacked as pseudospheres in a cavity at the top of a tuballoy block 12" high and 8" on a side, and the assembly tamped by locating it inside a doughnut shaped water tank whose tamping effect is equivalent to the tamping caused by personnel necessary for hand stacking."

Report discussing an experiment to reinvestigate the spontaneous fission of 48 (Pu-238) in an effort to determine a more accurate value for the spontaneous fission constant that was found in a previous experiment.

Abstract: "The thermal and electrical conductivities of a series of Pu-Al alloys have been determined in the range 0.12 atomic percent Pu. The conductivities are approximately proportional to the volume of free aluminum."

Abstract: "Decontamination factors of the order of 10-4 were obtained for Beta and Gamma emitters present as fission products when uranium was precipitated from 50 mC activity level solutions as uranyl oxalate under normal uranium yield conditions for three cycles (~60%). Factors of the order of 10-3 were obtained by the use of this reaction with similar solutions under relatively high uranium yield conditions for three cycles (~90%). The uranium peroxide precipitation reaction proved to be of no value on such solutions, yielding decontamination factors of only 17.1 Beta emitters and 1.2 for Gamma emitters for three cycles."

The following report describes procedures taken to utilize the photelometer to procure the most rapid and reliable determinations, but the goal of the tests presented was to create satisfactory dispersions of particles to analyze.

Abstract: "The general utility of vacuum evaporated films is discussed. The characteristics that makes this technique most useful are the uniformity of the films, the easy control of their thickness over a large range, and the adaptability of the system to different metals and compounds. The design of a vacuum evaporator should provide adequate pumping speed, cooling of components, filament heater supply, and general flexibility and adaptability of the components to different materials. The design of filaments or boats and the evaporation of Al, Ag, Au, Li, Na, UCl4, ThF4, Be, SiO, Nal (Tl), U, and UO2 are considered. Special attention is given to the problem of obtaining uniform layers of UO2 on a large, flat target relatively close to the source."

The following report describes the high pressure and temperature homogeneous reactor experiment which has been started at Los Alamos, as well as the hazards and safety aspects for the experiments.

The following report investigates part of the variability of the computed fall-out intensity patterns due to the variability of the winds, on the basis of winds from four Pacific shot days. An extreme case from Operation Sandstone is also considered.

The following report describes the findings of air samplings taken that followed the Wasp detonation of Operation Teapot.

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 following report presents a discussion of the method for hydrodynamic problems, together with some new considerations that have arisen concerning the method.

This report follows experiments on the behavior of helium when interacting with shock waves and the physical radioactive evidence following.

Abstract: A five-crystal scintillation gamma-ray spectrometer was constructed for use as a Compton coincidence spectrometer or as a pair coincidence spectrometer. Preliminary tests are discussed. The efficiency in either mode of operation was found to be low; however, the backgrounds were favorable and good definition of characteristic lines was achieved...Future tests and plans for improvements are discussed."

Abstract: "A description of the instrumentation for neutron flux measurement from Kiwi-A at NTS is given as some discussion of start-up considerations, detector design, system response adjustments, and power calibration of the reactor at some low level of power."

From abstract: "A general and systematic development of reactor computing methods and detailed application given in Report LAMS-2255 separately is supplemented in this report for a few specific systems of interest to the Rover program. Neutron cross sections, reactor description, and computed results are given for a reactor required to have a constant (radially) power distribution at high temperatures."

From abstract: "This report discusses a special handling procedure devised to prevent contamination of high-purity gold while processing the metal from cast billet to final sheet. Gold of 99.99% purity was cast into rectangular billets and rolled into sheet whose final dimensions were 48 by 12-1/2 by 0.015 inch...As a final step, the sheet was annealed dead-soft in preparation for subsequent forming operations."

The bibliography provided investigates the following sources: Chemical Abstracts 1947-1950., Metallurgical Abstracts Vols. 1-18., ASM Review of Metals Literature Vols. 1-6., J. Institute of Metals Vols. 78-80 (No. 7)., Physics Abstracts 1937-1950.

Report discussing the reaction of uranium with pure water. The reaction was followed by using a method of measuring hydrogen evolution.

From abstract: "To seek information for a better understanding of the phenomena involved in fall-out, a fireball effect was simulated in a small closed room by subjecting various materials to a high-current (~360 amp.) are produced between graphite electrodes, and anode being impregnated with radioactive materials. The time duration of the arc, power dissipated, and distance from the samples were controlled. The radioactivity which remained airborne, that which settled out onto the floor and its distribution, and that deposited on the test material was measured, and percentages of the total measured activity were determined."

An estimate was made of the upper bound for the half-time of dissociation at 100 atm for ammonia, methane, and propane at 2500 deg K and hydrogen at 5000 deg K. In each case a unimolecular reactron in the homogeneous gas phase was chosen as most suitable for this purpose. Slater's theory has been used to estimate the necessary frequency factors. The upper bounds to the half- time for dissociation range from 3 x 10⁻⁷ to 6 x 10⁻⁶ sec. Extrapolation of decomposition rate data obtained at --1000 deg C and 1 atm pressure gives smaller values for the half-time of dissociation.

This report describes the optical analogue that contains an optical filtering system which controls the intensity of light according to the assumed initial distribution of activity over height and particle size and according to the assumed decay rate, a size control system which depends on the lateral dimensions of the cloud of debris and adjusts the size of the light beam accordingly, and a position control system which moves the beam to the correct position on the plate as determined by the wind structure and the time of fall of the particles.