Abstracts and Available Papers Presented at the
1999 International RERTR Meeting

HIGH DENSITY URANIUM SILICIDE WITH EXCESS URANIUM

Asmedi Suripto, Soedyartomo Soentono and Iyos R. Subki
National Nuclear Energy Agency
Email: asmedi_s@batan.go.id
Indonesia

Prayoto
Gadjah Mada University
Indonesia

Gerard L. Hofman
Argonne National Laboratory
Illinois, USA

ABSTRACT

An experiment to prepare higher density fuel based on uranium silicide using excess uranium has been carried out.  The weight percentage of uranium in the melt was chosen to exceed that of U in U3Si2 thus resulting in an ingot density of approximately 15.5 Mg/m3.  The melt of uranium and silicon was quenched and the ingot so obtained was pulverized and fabricated into fuel plates with aluminum powder as the matrix material and with aluminum alloy as the cladding material.  Excess uranium metallic is known to have poor behaviour under irradiation.  However, when suitable heat treatment is applied to the fuel plates this uranium will react with the aluminum matrix to form irradiation-stable UAlx.  The formation of UAlx from the excess uranium and aluminum matrix has been found to take place at hot-rolling temperatures of fuel plates, i.e., in between 450 and 550°C, for an extended period of heating time.  The higher the annealing temperature, the shorter the annealing time required for reaction.  By ultimately having UAlx in the meat of the fuel plates, replacing the metallic uranium, one can get rid of the undesirable irradiation behaviour of uranium while achieving the purpose of having higher uranium loading in the fuel plates.  A simple calculation considering the amount of matrix material available for alloying reaction with free uranium in the dispersion shows that a dispersion fuel meat using this new fuel can reach a loading density between 6 and 7 MgU/m3.

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