Leaching of 53 MW/d kg U spent nuclear fuel in a flow-through reactor

Abstract

The dissolution behaviour of powdered commercial spent fuel (UO 2 with burn-up of 53MW/dkgU) has been studied in a carbonate-containing solution ([HCO 3 - ] = 0.001 mol dm -3 ) by using a flow-through reactor specially designed for the use in a hot cell. This method allows studying spent fuel dissolution while avoiding the parallel process of secondary solid phase formation. The dissolution behaviour of U, Np, Pu, Sr and Cs was studied. The main trend of the results obtained in this work is that only neptunium releases congruently with uranium (FIAP NP /FIAP U = 1.21 ± 0.01) because both strontium and caesium have higher FIAP values (FIAP Sr /FIAP U = 2.3 ± 0.8; FIAP C s/FIAP U = 5 ± 1) and plutonium lower (FIAP PU /FIAP U = 0.07 ± 0.02). The FIAP value for uranium at the steady-state is 4(±2) x 10 -4 .