System Design of a Refitable Supercritical Heavy Water Primary Heat Transport System for Pressurized Heavy Water Reactors

Abstract

Current Pressurized Heavy Water Reactors (PHWRs) have thermal efficiencies of about 30%. A significant increase in thermal efficiency can be obtained by operating at higher temperatures using supercritical water coolant. Supercritical water cycles have not been used in nuclear power plants due in part to the in-core high neutron absorption and material degradation of high temperature alloys typically used in thermal plants. This paper examines the replacement of the primary heat transport system (PHTS) and fuel channels in an existing PHWR with a supercritical heavy water PHTS. The in-core materials, thermal hydraulics and passive safety heat transfer are described. The out of core main heat transport loop is described including integration of the primary side high pressure turbine and interfacing with the plant main steam system. A benchmark application is examined resulting in a 100% increase in electrical output.