Preliminary engineer's flow sketch and process description, Redox feed preparation from current metal

摘要

The basis feed to the Redox plant is 5,000 lb/day of uranium, supplied both as current irradiated uranium metal slugs in jackets, and as uranium compounds from the existing metal waste storage tanks. The proportions of the two feeds are chosen according to the enrichment level of the irradiated metal, so as to give a plutonium production of about 650 gm/day. The design basis has been taken as 0 to 1,500 lb/day U from the waste storage system and 2,000--5,000 lb/day of irradiated metal. Only the feed preparation from irradiated metal is discussed in this process description, and a basis of 5,000 lb/day is used throughout. The metal feed has associated with it 172.5 lb. Al and 2.5 lb. Si as slug jackets, and contains about 650 gpm. plutonium and 3 (times) 10(sup 5) curies of gamma-emitting fission products (FP). The purpose of the feed preparation section is to remove the aluminum and silicon, and to dissolve the uranium as an aqueous solution for feed to the Redox extraction battery. Secondarily, it is tentatively proposed to provide equipment in this section to achieve a preliminary decontamination from ruthenium, which is poorly handled by the Redox extraction system, and from FP which are adsorbed by the filter aid used in the clarification step. The product of the feed preparation section is an aqueous solution of uranyl nitrate hexahydrate of 59.4% (2 M) concentration, with part of the stoichiometric nitrate ion neutralized by NaOH, and containing nearly 2% sodium dichromate as an oxidizing agent. It contains 99.9% of the plutonium originally in the slugs, and perhaps as little as 0.3 (times) 10(sup 5) curies of gamma-emitting FP.