Electrical Safety Solutions for Small Modular Reactors (SMRs) and Fusion Applications

The Nuclear Regulatory Commission (NRC) refers to both non-light water reactor (non-LWR) designs and small modular light water reactors (SMRs) as advanced reactors. SMRs are a subset of light water reactors that are designed to be more compact, scalable, and potentially safer, often incorporating passive safety systems and advanced engineering designs compared to traditional large-scale facilities. Non-LWRs, on the other hand, use distinct technologies, fuels, and coolants, broadening the spectrum of nuclear energy applications.

Nuclear fusion represents a different approach to energy production. Instead of splitting atoms, as in fission, fusion combines two atomic nuclei to form a heavier nucleus, releasing large amounts of energy. This reaction occurs naturally in the sun and stars, and researchers are working to replicate these conditions on Earth using machines such as tokamaks and stellarators. Unlike fission, fusion does not produce long-lived radioactive waste, which makes it a promising future energy source. However, fusion machines are not self-sustaining reactors; they require a continuous external energy supply to maintain the extreme temperatures and pressures necessary for fusion to occur. The NRC is actively engaging with stakeholders to understand the regulatory considerations associated with potential future fusion facilities.

The operation of both SMRs and fusion facilities demands elevated levels of predictive monitoring and electrical safety. Before medium-voltage power circuits are energized, they are typically maintained in an ungrounded state. During this stage, insulation monitoring devices (IMDs) are used to verify that no insulation faults are present. This “offline” monitoring approach provides assurance that the system is safe to energize.

The communications side of these systems also requires continuous supervision. IMDs play a critical role here as well, helping to ensure that no ground faults or imperfections interfere with sensitive communication systems. Once the power system is energized and transitions into a grounded state, residual current monitors (RCMs) are deployed to maintain continuous oversight. These devices help ensure that no ground faults are introduced into the process, providing uninterrupted safety during ongoing operation of magnetic field systems and tokomak arrays.

Bender’s solutions extend beyond these monitoring functions. Our IMD and RCM portfolio builds upon decades of proven application in traditional nuclear fission plants, where insulation monitoring and EDS fault location systems are widely used around the world. These systems are known for their ability to provide predictive insights, helping operators identify potential problems before they escalate into costly downtime. Real-time monitoring and fault location significantly shorten diagnostic time, enhancing system availability and overall safety.