GEL-ADDITION PROCESS CHEMICAL STUDIES. Quarterly Progress Report No. 4, April--June 1967.

Abstract

Development of the Gel-Addition Process for mixed urania-plutonia fuels has continued. UO^ sols have been prepared by the ORNL Formate Process. Gel spheres were made by drying sol droplets in a recirculating column containing a 2-ethyl hexanol bath. Carbon analyses at various steps show that at least half the carbon added (as urea and formate during sol preparation) remains in the sol. Gelation roughly triples the carbon level (C/U atoms ratio in gel = 1. 5). A study of the gelation bath composition showed that nitrated organics do not appear in sufficient quantity to constitute a hazard. Oxidation of Pu(IV) to Pu(VI) by nitrate has been confirmed to be first order in Pu(IV). Apparent half-times have been measured at 30 minutes and 10 minutes. Plutonium pickup by U0 2 gel has been found to be extremely rapid. In contacting runs lasting between 10 and 20 seconds, Pu/U+Pu reached several percent from Pu(IV) solutions. Ceramographic procedures have been developed for polishing and photographing unfired gel. Most gel samples examined show cracking, Capsule design for in-pile testing of mixed oxide is complete. Progress for the fourth quarter ending June 30, 1967 is reported. The project is supported by the U.S. Atomic Energy Commission under Contract No. AT(30-l)-37 14.