At the present time, cerium-144 and premtheium-147 are the two fission product rare earths that appear most promising for use as the heat source in isotopic power units. Under proper conditions, cerium and the trivalent rare earths can be extracted from the Purex fission product waste stream as an insoluble sodium-rare earth double sulfate. A reprecipitation as the double sulfate, dissolution of the hydroxide, serves to give almost complete separation from the corrosion products, inert constituents of the waste, and from most of the fission products. The cerium and the trivalent rare earths must then be separated from each other. In the case of cerium recovery, it is necessary to remove the trivalent rare earths in order to maximize the specific activity of the cerium. If promethium is the desired product, a preliminary cerium separation is desirable to protect the ion-exchange resin (used for separating promethium from its adjacent rare earths) from the intense high-energy radiation from cerium.

Report that "describes an instrument that nondestructively tests uranium fuel element cores by ultrasonic methods" (p. 2).

The decontamination of the present Hanford reactors involves a once-through cleaning operation. Considerable interest has been shown in determining the feasibility of this once-through technique for cleanup of certain portions of the NPR system. This is the second interim report of a series that covers tests performed in the 242-B Single Pass Flow Facility. The first was distributed in January, 1960.

The majority of two-phase flow problems involving equations of state are solved by use of point-wise utilization steam table values. In this manner, problems involving the use of the various flow equations of continuity, momentum and energy are generally forced into iterative solutions. Considerable effort towards the development of an analytical expression for the state equation seems indicated so as to simplify the analysis of two-phase problems, particularly the transient cases. The question of instability of state and mixture condition is particularly apparent in the analysis of systems undergoing phase transformation as demonstrated by the significant difference between simple theory and experimental critical flow determinations. The assumption of homogeneous, equilibrium mixtures is indicated as a first attack upon the problem.