Improvement of single-phase subchannel analysis code ASFRE-III; Verification analysis of fuel pin heat transfer model and pressure loss model

not registered; Ohshima, Hiroyuki

As the part of the improvement of single-phase subchannel analysis code ASFRE-III, verification study about fuel-pin heat transfer model and flow resistance model of the code was carried out. Temperature distributions in a fuel pin predicted by the fuel-pin heat transfer model of ASFRE-III were compared with those calculated by the structure analysis code FINAS, which has been well validated and applied to various structure analyses, using the same boundary conditions. The comparison showed that the results by these two codes agreed with maximum difference of 1 %. and therefore the validity of the model was confirmed. With respect to the flow resistance model, distributed resistance model (DRM), which can enhance the consistent description of the fluid flow and wire-spacer interaction, was examined through analyses of two hydraulic simulation tests using the fifth mock-up fuel subassembly for the prototype LMFBR and the second mock-up fuel subassembly for the experimental rector. The calculated pressure difference between pressure measurement taps whose positions were near the top and the bottom of the fuel-pin bundle agreed with the measured data of both tests. The predicted pressure distribution in a horizontal cross section was also compared with the calculational result by the finite element analysis code SPIRAL and agreement was good.