Advanced Design of ACR-1000® Moderator System

Abstract

Advanced design features incorporated in the ACR-1000 moderator system are presented in the paper. The thermalhydraulic behaviour of the moderator flow in the calandria vessel, with 3D computer simulation using the MODTURC_CLAS code, is also discussed. Significantly improved D2O flow and temperature profiles in the calandria vessel are demonstrated by the simulation results. The moderator flow through the reactor core is reinforced with the natural buoyancy in the region. This results in the D2O temperature increasing monotonically from the bottom to the top of the calandria vessel. Large subcooling margin is also maintained in the moderator, which prevents sustainable dry-out on the surfaces of the fuel channels.