Subchannel analysis of a fast reactor cooled by supercritical light water

The concept of a high temperature fast reactor cooled by supercritical wate r (SCFR-H) was developed for achieving high thermal efficiency and a compac t reactor system. The core characteristics were obtained from single channe l thermal-hydraulic analysis. Thus, it is necessary to carry out subchannel analysis to estimate the effect of local power peaking and cross flows. Fo r this purpose, a subchannel analysis code is developed. It is verified by comparing the results with experimental data of High Conversion Pressurized Water Reactor (HCPWR). Sensitivities of the outlet coolant and cladding te mperature to the subchannel flow area and local power peaking are high. One of the reasons is that the ratio of the coolant flow rate of SCFR-H to the power is smaller than that of LWR. Another reason is that, temperature of supercritical water is more sensitive to the enthalpy change above 450 degr eesC. The outlet coolant temperature distribution can be flattened by reduc ing the area of the peripheral subchannels and by enhancing the mixing betw een the subchannels. (C) 2000 Elsevier Science Ltd. All rights reserved.