Assessment of the HPLWR Thermal Core Design

Abstract

The core design concept of the High Performance Light Water Reactor features a thermal neutron spectrum, provided by additional moderator water in water boxes and in gaps between assembly boxes, and a heat-up of the coolant in three steps from 280°C to 500°C. Intermediate coolant mixing has been foreseen by mixing chambers underneath and above the core to overcome the hot channel issue of a core design with a large enthalpy rise. The paper summarizes the various analyses performed within the project HPLWR-Phase 2 with respect to this core design and assesses how far the initial design target has been met.