Conceptual Design of Pressure Tube Light Water Reactor with Variable Moderator Control

An innovative light water reactor concept, which holds a great promise of improving the fuel utilization, has emerged recently based on an idea of the “breed & burn” mode of operation. The novel concept, named PTVM LWR, is a pressure tube type reactor of similar design to ACR-1000, but differing in two aspects. First, the inter-fuel channels spacing, surrounded by the calandria tank, contains a low pressure gas instead of heavy water moderator. Second, the fuel channel design features an additional/external tube (designated as moderator tube) connected to a separate moderator management system. The moderator management system is designed to vary the moderator tube content from “dry” (gas) to “flooded” (light water filled). The moderator variation results in a neutron spectral shift, which allows the implementation of the “breed & burn” mode of operation. In this talk, the novel reactor core design and the physical principles underlying its operation will be described and discussed. Finally, possible research lines for future investigation and continuous design developments will be discussed.