Concept of a Small Modular SCWR with Horizontal Fuel Assemblies

Based on the concept of the High Performance Light Water Reactor (HPLWR), an innovative concept of a small modular reactor is presented, which shall have smaller peak cladding temperatures than the HPLWR due to better coolant mixing, and which shall enable a passive residual heat removal by natural convection. The core is designed with horizontal fuel assemblies of 40 fuel rods each, including an internal water channel to improve moderation. Supercritical water is heated up in seven steps, when running through these assemblies, and the reflector around the core is used as mixing channels. A single channel analysis, considering an average fuel assembly and a hot channel, provides a first estimate of pressure losses, coolant and peak cladding temperatures. More design optimization and analyses will be needed, however, to assess the feasibility of such a concept.