The transport of fission products from points of origin in unclad graphite matrix-type fuels to the reactor circulating system involves, as one of the steps. diffusion through the graphite matrix to the fuel element surface. As pointed out by Rosenthal. the fraction of a given fission product chain actaally reaching the fuel element surface will be small if the time for transport through the graphite is long compared to the half-lives of the volatile members. An important problem, therefore, is the determination of the effective transport rates of the various mobile elements and their daughter products of interest through various graphites suitable for use as fuel element compacts. as functions of temperature over the range of greatest immediate interest to reactor designers. The upper end of the range need not exceed about 1000 deg C. The transport of helium and arbon through various graphites has been the subject of considerable study by Watson. Evans, and other,. and a prelimilnary investigation of the high temperature transport of some ordinarily non-volatile elements has been carried out by Saunders. This work is briefly reviewed in relation to the final problem and the areas in which further information is needed most by reactor designers …

This report, from the Chemical Processing Department at HAPO for February 1961, discusses the following: Production operation; Purex and Redox operation; Finished products operation; maintenance; Financial operations, facilities engineering; research; employee relations; and special separation processing and auxiliaries operation.

Experiments were carried out to determine the erosion, oxidation and dimensional characteristics of purposely defected fuel elements containing unsintered UO2 powder prepared by the swaging technique. The experiments were conducted in an out-of-reactor loop under superheat conditions of pressure, temperature, flow velocity and steam chemical composition.