, ? Code-to-code comparison ? issues requiring clarifications and improvements: ? Power generation in non-fuel regions. Enable capability, photon transport needed or not ? ? Doppler constant: differences up to 30%, largely unexpected

, ? Void effect in leakage dominated sodium plenum regions: differences up to 25%. ? Nuclear data effect (JEFF versus ENDF) mainly on the effective multiplication factor. ? Ongoing: characterization of other reactivity effects due to ? Thermal expansions of diagrid, wrapper, fuel and cladding

?. Ongoing, Thermal-hydraulic simulation of void evolution in Na plenum, p.16, 2015.