Heat transfer problems in FA of VVER-SCP

Three concepts of reactor plant (RP) with supercritical water coolant VVER-SCP (SCWR), which refer to the Generation-4 systems, were developed in Russia: — VVER-SCP-1700 - one-circuit high-power RP, with fast-resonant neutron spectrum in the core; — SPCS-600 - two-circuit RP, with pseudo-vapor supercritical primary coolant and fast neutron spectrum in the core; — VVER-SCP-I - two-circuit RP, with supercritical water coolant in the primary circuit and regulated neutron spectrum. Up to the moment, OKB ^GIDROPRESS implements engineering development of VVER-SCP-1700 and performs thermal-hydraulic analyses. Several problems, which were discovered during the subchannel calculations of the coolant flow in FA of one-circuit VVER-SCP-1700 must be studied with the first priority. The report emphasizes the problem of the displacement of coolant from the more heatstressed part of the bundle to the less heat-stressed. The results of the calculations concerning this problem are presented. New specification of the future thermal-hydraulic subchannel calculations in the framework of development and verification of TEMPA-SC code is presented.