Investigation on applicability of subchannel analysis code ASFRE on thermal hydraulics analysis in fuel assembly with inner duct structure on sodium-cooled fast reactor

Kikuchi, Norihiro  

In the design study of a sodium-cooled fast reactor (SFR) in JAEA, the adoption of a fuel assembly (FA) with an inner duct structure called FAIDUS has been investigated to enhance safety of SFR. Due to the asymmetric layout of fuel rods by addition of the inner duct, the velocity and temperature distributions in FAIDUS may differ from that in typical FA. It is need to confirmed that applicability of the subchannel analysis code named ASFRE which has been developed as a FA design tool, to thermal hydraulics analysis in FAIDUS. Because the reference data on the thermal hydraulics in FAIDUS have not been obtained by the mock-up experiment, the code-to-code comparisons with numerical results of ASFRE and those of a CFD code named SPIRAL was conducted. The applicability of ASFRE was indicated through the confirmation of the consistency of mechanism of the specific temperature and velocity distributions occurring around the inner duct between the numerical results by ASFRE and SPIRAL.