Monthly report the progress and development of improved zirconium alloys for service in superheated water and steam. This report covers the period between April 1 to April 31, 1961 and was conducted by the United States and the European Atomic Energy Community (EURATOM).

The development of a miniature probe was desired for measuring approximate single nuclide beta dose rate in solution and in various animal organs. This probe designed for biological experiments, was to have maximum possible sensitivity to detect low levels of nuclide concentrations. The desired dimensions of the light pipe were to be approximately one-fourth-inch diameter with lengths of three to twelve inches.

In order to prevent dangerous concentrations of combustible gases such as hydrogen and ammonia in Redox dissolvers, a continuous analysis of the off-gases is needed. Hydrogen is evolved from most fuel element dissolution processes now used or planned for use at Redox. Ammonia is also released from ammonium fluoride dissolution of zirconium and caustic dissolution of aluminum cladding. Oxides of nitrogen and hydrogen are formed during nitric acid dissolution of uranium or plutonium-aluminum alloys. Since no fixed ratio exists between the concentrations of any two of these gases, the determination of combustible gases in complex mixtures is not possible with a single bulk property analyzer.

With the construction of nuclear reactors, a great deal of emphasis has been placed upon studying the effects of radiation on the solid materials of construction. It has become necessary to consider radiation exposure as an environmental entity along with others so established such as temperature, electrical and mechanical stress, chemical resistance, weather, etc. Problems concerning the study of the behavior of materials that are thus increased when radiation exposure has to be evaluated singly or in combination with one or more of the other environments. This paper presents the general plan of attack being followed to solve such problems that arise when plastics and elastomers are placed in radiation fields. These studies were undertaken for two primary reasons: (1) to obtain engineering data for practical applications of the desirable properties of these materials for such devices as o-rings, gaskets, pipe, and electrical insulation; and (2) to use these data to enable a better understanding of the nature of radiation effects on these materials. The initial phase of the program is the screening of materials by subjecting them to various degrading environments and recording property changes. Thus, with data on how these materials performed, more comprehensive studies could be made …

Abstract: "A cylindrical coil has been designed for pulsed field operation suitable for use in a model thermonuclear reactor. The coil has an eight-inch inside diameter and a length of fifty-one inches. Magnetic mirrors at the ends consist of double-layer solenoids six and one-half inches long designed to slip over the main coil. Subsequent models of this coil have been fabricated which improved the electrical insulation provided by the bonding materials and the mechanical rigidity of the coil. Peak central fields of fifteen kilogauss and mirror fields of thirty kilogauss have been obtained."

Abstract: "Aluminum-clad nickel-plated uranium is corrosion resistant in boiling water. Samples with intentional defects in the aluminum-nickel clodding layers, after testing for more than 300 hr. showed no sign of rapid failure. The study of electroplated metals on uranium for aluminum cladding has defined the effects of several processing variables on the corrosion resistance. The quality of the uranium and the quality of the aluminum-nickel bond were important. Heat treatment and vacuum outgassing of the nickel-plated uranium prior to aluminum cladding were beneficial, and minimizing the amount of air present in the hot-press assembly was desirable. Variation in the steps for electroplating on uranium did not affect the corrosion resistance of aluminum-clad uranium."

Abstract: "A titrimetric method for the determination of fluoride in plutonium is reported. Prior to a steam distillation of the fluoride, the bulk of the plutonium is separated by precipitation of the sulfate. The fluoride in the distillate is titrated at a pH of 3.2 with 0.001 M thorium nitrate, using chrome azurol-S indicator. Applied to samples containing 1 to 15 parts per million fluoride, the recovery is 87% and the precision on the 95% confidence level is +/- 0.65 ppm."

This technical report is a summary of unclassified theoretical work on propagation of one-dimensional shock waves and on the propagation of spherical shock waves in gases.

Two xenon extraction runs were made this month. It appears that a small design change in Trap #2 will be necessary so that a dry ice-trichloroethylene slurry can be used for coolant rather than liquid freon. For each of the runs this month the enriched generator was exposed for four hours in the est pile operating at 100 watts. A period of eight hours for cooling and xenon builidup was allowed before the collection and separation runs were started.

This report covers an investigation meant to find the feasibility of producing corrosion resistant zirconium from sponge by special melting techniques. The zirconium metal has certain required specifications, such as: the metal must be free from bafnium, and it must be free from other impurities of undesirable neutron cross section.

The importance of fast neutron fission (i.e., fission caused by neutrons before being slowed down) was recognized by Szilard, and calculations similar to the present one have already been carried out by him, Feld, Ashkin, Wheeler, Wigner and others. The purpose of the present paper is to give a general formula for the contribution of fast fission to the multiplication constant, which will include all the cases already considered and will be applicable to more complicated geometries than those considered by the previous writers.