Development of a small modular boiling water reactor combined with external superheaters

The balance between sustainability, energy security and affordability are important trade-offs to consider in decarbonizing the current energy system. The two practical alternatives for moving forward seem to be either reducing the energy storage costs to enable deployment the intermittent renewables on a large scale or developing an affordable and more flexible nuclear power. A small modular boiling water reactor combined with external superheaters offers a significant improvement to the conventional nuclear system. The potential benefits include improvement in cycle thermal efficiency, reduction in the size of the vessel, and the capability to adjust load while maintaining the reactor operation at 100% of its full power. In this paper, the conceptual design of a Small Modular Boiling Water Reactor (SMBWR) combined with external superheaters is presented along with investigation into some of its core design performance characteristics. It is found that the 4-batch in-core fuel management scheme offers a more favorable performance compared to the 3-batch scheme as it has lower power peaking, less excess reactivity, and more negative coolant void coefficient (CVC). The combination of a multi-batch fuel arrangement, coolant temperature variation, and control rods are required to control the reactivity swing in the SMBWR while keeping the power peaking below the safety limit throughout the depletion cycle.