Importance of fuel thermo-mechanical properties in a ULOF transient of a Sodium-cooled Fast Reactor used for minor actinides transmutation

摘要

In this work the relevance of thermo-mechanical properties of MOX fuel bearing minor actinides (MA) on the behavior of the reactor under an unprotected loss of flow (ULOF) transient has been studied An updated version of the SAS-SFR code able to analyze the initial phase of accident scenarios for sodium-cooled fast reactors fuelled with innovative oxide mixtures (U,Pu,Np,Am,Cm)O_2 has been used. The authors have considered the effect of MA in reactor kinetics (i.e. reactivity coefficients, power, and kinetic parameters) as well as in fuel thermo-mechanical properties (i.e. thermal conductivity, heat capacity, thermal expansion and melting temperature). The core design used in this work is the so-called Reference Oxide core of the CP ESFR project at end of equilibrium cycle. Additionally, a parametric study has been made in order to separate reactor kinetics and thermo-mechanical effect and to identify the importance of thermo-mechanical properties for the transient behavior and how precisely they should be determined experimentally for future MA-MOX fuels.