Abstracts and Available Papers Presented at the
1997 International RERTR Meeting

First Results of U3Si2 Production and its Relevance in the Power
Scaleup of IPEN Research Reactor IEA-R1m

Saliba-Silva¹, A. M.; Souza, J. A. B. ¹; Frajndlich, E. U. C. ¹; Perrotta, J. A.²; Durazzo, M.¹

¹Departmento do Ciclo do Combustivel
Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP)
Cidade Universitaria (USP),
Travessa R, 400 CEP05508-900 Sao Paulo (SP)
Brazil

²Divisao de Engenharia do Nucleo, IPEN/CNEN-SP

Abstract

The own supply of LEU U₃Si₂ is crucial for IPEN, since the whole scale-up of IPEN MTR IEA-Rlm reactor will rely on it. The Brazilian request for radioisotopes production is fully linked with the already made power scale-up from 2 to 5 MW for this reactor. IPEN now depends on fuel element material upgrading from U₃O₈ towards LEU U₃Si₂. The fuel plate productive technology from the powdered material is already well established, only needing simple making of minor adjustments, but to reach the stage of producing U₃Si₂ we need a fully settled chemical pilot plant in order to reach a LEU UF₄ productive routine. Complementing this process, it was also needed to scale down the previous practice of uranium magnesiothermic reduction to around a sub-critical safe uranium mass of approximately 3000g. To complete the metallurgical processing, it is being developed the production of U₃Si₂ in a vacuum induction furnace. Some experiments to get this intermetallic, using natural uranium, have already been carried out in order to build up a general idea of the future process of LEU U₃Si_2. These experiments are described in this paper and also some of the initial characterization results, such as the qualification pattern of the ingot. It is also discussed some new features of inhomogeneity of solidified phases that may be deleterious to future production routine.