Abstract
Grid Appropriate Reactors (GARs) are a component of the U.S. Department of Energy�s (DOE�s) Global Nuclear Energy Partnership (GNEP) program. GARs have smaller output power (<~600 MWe), than those intended for deployment on large, tightly coupled grids. This smaller size is important in avoiding grid destabilization, which can result from having a large fraction of a grid�s electrical generation supplied by a single source. GARs are envisioned to be deployed worldwide�often in locations without extensive nuclear power experience. DOE recently sponsored the creation of an Instrumentation, Controls, and Human-Machine Interface (ICHMI) technology development roadmap emphasizing the specific characteristics of GARs [1]. This roadmapping effort builds upon and focuses the recently developed, more general nuclear energy ICHMI technology development roadmap [2].
The combination of the smaller plant size, smaller grids, and deployment in locations without extensive prior nuclear power experience presents particular infrastructure, regulation, design, operational, and safeguards challenges for effective GAR deployment. ICHMI technologies are central to efficient GAR operation and as such are a dimension of each of these challenges. Further, while the particular ICHMI technologies to be developed would be useful at larger power plants, they are not high-priority development items at the larger plants. For example, grid transient resilience would be a useful feature for any reactor/grid combination and indeed would have limited some recent blackout events. However, most large reactors have limited passive cooling features. Large plants with active safety response features will likely preserve trip preferential grid transient response. This contrasts sharply with GARs featuring passive shutdown cooling, which can safely support grid stability during large grid transients. ICHMI technologies ranging from alternative control algorithms to simplified human-interface system designs are key to enabling GARs to respond properly and thereby stabilize the grid during transients.
