Zirconium alloys matrix as innovative material for composite fuel

Abstract

A novel class of zirconium alloys is suggested as fuel matrix. They are “deep” ternary or quaternary eutectics having relatively low melting point i.e. from 963 to 1133K in comparison with pure zirconium and intended for use as a matrix of dispersion high uranium content fuel (CERMET and METMET) particularly for thermal reactors. For fast reactors and MA burning Zr–Ti based alloys are proposed that have resistant metallurgical bonds between fuel and steel cladding. Investigations have been carried out on the structure and properties of the alloys as well as the specific technologies of their fabrication, in particular via induction furnace melting. The alloys may be also produced in the amorphous state as granules and strips. It is shown that thanks to their capillary properties they might be applied in brazing dissimilar materials. Based on novel zirconium matrix alloys high uranium content fuel compositions were produced. They have high thermal conductivity and compatibility as well as 25–50% higher uranium content than for VVER and PWR fuels.Fuel pins are fabricated by capillary impregnation method. The use of dispersion fuel with novel zirconium matrix alloys improves neutronics characteristics of reactor cores and might lead to extension of burn-up, low operating temperatures and serviceability under transient conditions.