Worldwide development of accident tolerant fuels, areas of study, claddings, and fuels

Abstract Until a few years ago, very few considered the possibility of using fuel systems in light water reactor that were not based on a zirconium alloy and uranium dioxide (UO2). All standards and guidelines developed over the last 60 years in the commercial nuclear power business are based on Zr/UO2. Any improvement over the decades was to understand and solve issues related to the performance of Zr/UO2. Now, there is a possibility for newer materials in power reactors, and regulatory bodies and trade organizations may be accepting this change as an unavoidable reality. The newer accident tolerant fuels ATF can be classified broadly into (1) newer claddings and (2) newer fuels. Each one of the cladding and fuels main groups has subgroups. In the cladding, subgroups are (1) coated zirconium alloys, (2) monolithic FeCrAl alloys, and (3) ceramic composites or SiC/SiC made of SiC fibers embedded in an SiC matrix. The subgroups in the fuels are (1) modified or doped UO2 and (2) high-density fuels including uranium nitride and uranium silicide. The most near-term concepts for implementation may include coated zircaloy cladding and modified urania fuel. The second closest implementation could be FeCrAl cladding for urania fuel. The ceramic composite SiC/SiC for cladding and the higher density fuels UN and U3Si2 are concepts that may need longer term developments. In the United States (and in many other countries), the entire nuclear power industry is prepared for the changes. In the first few years of development of the ATF concepts, the regulatory agency and the commercial side of nuclear power were observant bystanders. However, in the last few years, they became fully engaged. Currently, utilities are working closely with the fuel producers to have one or more concepts installed in their commercial reactors within the next quinquennium. The supportive organizations for the utilities such as the Electric Power Research Institute and the Nuclear Energy Institute are dedicating technologists to evaluate the benefits offered by the newer ATF concepts. The regulatory body (Nuclear Regulatory Commission) is investing in personnel to work in parallel with the US Department of Energy and the fuel vendors to allow a full reload into a reactor as soon as technically possible. The funding at federal level in the United States is robust for universities, national laboratories, fuel vendors, commercial utilities, and trade organizations to be working collectively with the main goal of making nuclear power plants safer to operate and to continue having the option of using nuclear power to supplement other clean energy sources and to minimize the indiscriminate burning of fossil fuels in order to generate electricity. It is always rewarding to have variety of technological and engineering organizations working with the same goal of making nuclear power stations more robust and safer to operate. Different technologists with diverse backgrounds would look at and evaluate the same issue of increased safety in reactor operation from a different perspective. The Fukushima accident was a critical unfortunate event for nuclear power generation; however, it eventually galvanized the industry to offer solutions for the continuing use of clean nuclear energy.