Abstract

In this project we have identified three new missions for nuclear plants that will operate in the Japanese energy market in the 2030s and beyond. They are (1) flexible electricity generation at existing power plant sites, to replace retiring coal/natural gas capacity, and to complement variable generation from solar and wind; (2) flexible co-generation of electricity and heat at industrial sites, to support the production of valuable products, including hydrogen for transportation; and (3) generation of power and heat for niche markets such as remote communities/islands, military bases, mining sites, disaster relief, district heating, data centers, and freight ship propulsion. After assessing a broad set of reactor technologies, we selected three of them to satisfy the above missions, respectively: (1) a small modular boiling-water reactor for flexible electricity generation, (2) a high-temperature gas-cooled reactor for co-generation of electricity and heat at industry sites, and (3) a heat pipe micro-reactor for niche markets. We deem that such technologies can be deployed commercially in Japan by 2030, and have a high likelihood of meeting the important requirements for economics (i.e., cost competitiveness with liquified natural gas, low operation and maintenance cost), operational capabilities (i.e., load following, grid resilience), safety and security (i.e., insensitivity to external events, emergency planning zone limited to the site boundary). We developed notional layouts for three representative sites in Japan (i.e., TEPCO’s Higashidori power plant, Mitsubishi Chemical Co.’s Kamisu Ibaraki plant, TEPCO’s Hachijō-jima power plant) at which commercial demonstration of these reactor technologies could take place. The site layouts were informed by consideration of optimal construction and operations. Particular emphasis was placed on evaluating the merits of embedding the nuclear island below ground, to reduce seismic loads, reduce reactor building cost, and enhance physical security. Lastly, we explored several innovations in automation and digitalization of plant operation and maintenance that could make new nuclear plants even more cost effective and valuable to Japan.