Evaluation of wrapper tube temperatures of fast neutron reactors using the TRANSCOEUR-2 code

This paper deals with the thermal loading estimation of wrapper tubes using the TRANSCOEUR-2 code. This estimation requires a knowledge of two temperature fields: the first involves the peripheral sub-channel temperatures of each sub-assembly calculated by the design code CADET, and the second, outside the sub-assemblies, is the inter-wrapper flow temperature field calculated by the thermal-hydraulic code TRIO-VF with boundary conditions taken from CADET. Theoretical models of the three codes are presented as well as the first TRANSCOEUR-2 wrapper tube temperature calculation performed on the European Fast Reactor (EFR) Core Design 6/91 (CD 6/91) under nominal power conditions. The results show a temperature variation of 115 degrees C between the bottom of the lower blanket and the top of the upper blanket fuel sub-assemblies in the center of the core and 95 degrees C at the core periphery. The wrapper tube temperatures are higher in the center than in the external core