Controls and Concepts of Operation for Load Balancing with IPWRs in a High Renewables Penetration Grid

The future of commercial nuclear power in the United States is uncertain in the wake of construction delays and several plant closings, especially in deregulated wholesale electricity markets with cheap natural gas and increasing wind and solar penetration. As a firm low carbon resource, nuclear power plants can serve a key role in climate mitigation strategies by displacing the natural gas generators that provide dispatchable peaking capacity in systems with large and increasing variable renewable energy (VRE) shares. Small modular reactors, or SMRs, are among a suite of new reactor technologies that might alleviate the time and cost overruns facing nuclear industry in the West and offer increased flexibility over the currently operating reactor fleet. Integral pressurized water reactors (IPWRs) will almost certainly be the first such SMRs commercially deployed as of this writing. The goal of this thesis is to develop and evaluate the performance of a control system for an IPWR power plant in a high renewables penetration grid. A reactor similar to the NuScale Integral Pressurized Water Reactor has been chosen as the candidate reactor for these control design and feasibility studies due to the availability of design data and research literature pertaining to the NuScale IPWR module and plant concepts. This reactor concept was modeled in the Modelica language and a fuzzy logic coordinated control system was developed in Simulink to achieve different load profiles that may be typical of an electrical system with a large share of VRE generation. The results of these closed loop control simulations demonstrated the efficacy of load balancing with an IPWR module plant with such a generation mix but with additional notional costs and penalties that are not inherent to baseload operation.