Static and transient analysis of a medium-sized sodium cooled fast reactor loaded with oxide, nitride, carbide and metallic fuels

Abstract

Transient analysis was performed for the BN600 reactor loaded with different types of fuels. In order to obtain core performance parameters and major reactivity coefficients needed for transient analysis, a Serpent model based on geometrical details of the BN600 sodium-cooled fast reactor (SFR) was first created. MOX, (U-Pu) N, (U-Pu) C and (U-Pu) Fs, as representatives of oxide, nitride, carbide and metallic fuels, were loaded into this Serpent model individually. Plutonium contents were adjusted to 16.3, 14.3, 14.5 and 12.6wt.% for these fuel cases respectively, aiming at the self-sustainability of plutonium. The safety performances of different fuel cases during the unprotected loss of flow (ULOF) and unprotected transient over power (UTOP) transients were then assessed by applying the TRACE code. The point kinetic calculation module in our TRACE model is constructed with safety related parameters obtained from our Serpent calculations.Based on our transient simulation results, comparing to other fuel cases, our nitride fuel case was proved to be able to provide the biggest margin to the working limits defined in this paper, concerning fuel melting, cladding rupture and coolant boiling. This enables the nitride fuel to be a competitive candidate for the BN600 type sodium cooled fast reactor usage.