The spontaneous fission rate of plutonium-240 has been redetermined and found to be 1.51 X 106 events/g/hr.

Hanford uranium contains minute angular inclusions which affect the microstructure, reactivity, and other important factors controlling the serviceability of the metal. Small quantities of the inclusions have been isolated by chemical means, and the x-ray diffraction patterns and chemical analyses of the isolated materials have been determined. As a first step in the identification of the inclusions present in rolled uranium, a search was made for a chemical method of separating the inclusions from the matrix metal.

The construction and operation of a fission gas generator, containing about 25 grams of uranium in the form of a powder with a high specific surface, are described in detail. The purpose of the work discussed in this report was to examine the feasibility of producing, separating, and assaying samples of Xe135 in preparation for a proposed measurement of the neutron cross section of this isotope. Krypton and xenon are separated by selective adsorption on charcoal at reduced temperature while iodine is removed by charcoal sorption at room temperature.