5-6th Thermal and Fluids Engineering Conference, 2021
The nuclear industry is at a crossroads. Over the past several years some units have pre-maturely shutdown and entered into decommissioning. Other operating units are clearly stressed economically and are considering pre-mature closure. The market forces are harsh. Yet, there are compelling reasons for the nuclear industry to continue to provide an important contribution to the energy sector and possibly even expand. Global efforts to address climate change and to meet the energy needs of developing nations are likely to require large, new sources of clean, carbon-free energy. Currently, nuclear plants provide roughly 20% of the electrical power capacity in the U.S., and represent approximately 60% of U.S. carbon-free production. If world-wide demand for increased carbon-free electrical production continues, nuclear must certainly play a role. The U.S. nuclear industry is responding by proposing a wide variety of advanced non-light water reactors; gas-cooled, liquid metal cooled, molten salt cooled, and what are termed “micro” reactors cooled using heat pipes. Both fast and thermal spectrum reactor designs are under active development, with fuels ranging from TRISO and metallic to liquid fuel salts. These designs and new fuels are built upon many years of experience with light-water reactors and offer significant improvements in safety, operation and economics. Modeling and simulation of these new designs and their behavior during hypothetical accident scenarios represents a challenge to both design and licensing, in large part to uncertainties in the thermal/fluid behavior. While the opportunities for improved safety and economics are apparent, the thermal-fluid uncertainties must be addressed. Nuclear reactor thermal-hydraulics has always been a challenging technical area as the industry has developed both conventional and passively cooled light-water reactors and improved fuel designs. For non-LWRs, this is no exception. The nuclear industry, the U.S. Department of Energy,and the U.S. Nuclear Regulatory Commission are currently working towards an improved understanding of the safety of advanced designs, new fuel concepts, and development of the experimental database and analytical capability to simulate these new concepts.
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