Physics Performances of a Heterogeneous Fast Reactor Core Concept Studied in MASURCA

Experimental and theoretical work is now in progress at the Commissariat à l’Energie Atomique to support the sodium mixed-oxide fast reactor design calculations of the heterogeneous concept. The results obtained with the calculational method presently used are compared to the experimental values given by the PRE-RACINE program performed on the MASURCA facility. The following parameters are studied:

1. critical masses of heterogeneous configurations containing a single central fertile zone (R = 15 cm)
2. fission rate ratios f₈/f₅, f₉/f₅, and c₈/f₅ in the internal fertile zone and in the fissile zone
3. breeding gains of the different core zones
4. sodium void effects in the internal fertile zone.

The first results obtained with the new cross-section set CARNAVAL IV are given and compared to the values calculated with the previous CARNAVAL III set. The future development of the program is briefly described.