The group was established by the Nuclear Energy Subcommittee—subordinate to the Advisory Committee for Natural Resources and Energy (ANRE)—for the purpose of “redefining the societal value of nuclear power and identifying a way forward for Japan’s nuclear reactor development.”

At the meeting, prior to start of deliberations, a member of the ANRE secretariat made an itemized outline of the expected contributions from advanced reactors. Those, he said, included improved nuclear safety, decarbonization (supplying hydrogen and heat), stabilized electric power networks (via load following, etc.), reliable supply, economic security, and resolutions to nuclear waste issues.

Using the framework of evaluation axes for the value of developing advanced reactors, he referred to the following four points, asking the group for their evaluation of each:

— technology readiness level (TRL) and necessary R&D

— marketability at the time of practical implementation

— building specific development systems and international cooperation systems

— coping with regulations at the stage of practical implementation.

Next at the meeting, descriptions were given by individual representatives of the Japan Atomic Energy Agency (JAEA), Mitsubishi Heavy Industries (MHI), Hitachi, Ltd., and Toshiba Energy Systems & Solutions Corporation (Toshiba ESS) about their work on advanced reactor development.

OHSHIMA Hiroyuki, executive vice president of JAEA and a technical member of the WG, who had also given a presentation at the Nuclear Energy Subcommittee on March 28, reiterated an account of the Agency’s activities.

He was followed by KATO Akihiko, head of MHI’s Nuclear Energy Systems Division, who talked about the state of development of the advanced reactor lineup at Mitsubishi, including next-generation light-water reactors (LWRs), small LWRs, high-temperature gas-cooled reactors and fast reactors.

Among them is a portable nuclear microreactor (1 MWth or more, 5 kWe or more) that can be transported by container and has a “totally new” reactor core structure. It could allow for operation that is long-duration, remote, automatic, and maintenance-free, with fuel changes rendered virtually unnecessary. The microreactor is expected to be used at sites such as remote islands and rural areas, and wherever needed in times of disaster.

Next, KUME Tadashi, CEO of the Nuclear Energy Business Unit at Hitachi, explained his company’s small modular reactor (SMR) BWRX-300, its Resource-renewable Boiling Water Reactor (RBWR) and its Power Reactor Innovative Small Module (PRISM). He cited “technology continuation and ensuring experienced suppliers” as a leading issue in advanced reactor development, as identified in surveys of people of different ages with experience in plant construction, and of business partners and others.

Another person speaking before the WG was USUI Hidekazu, a director of Toshiba ESS, who emphasized the pursuit of reactors that are “excellent in [terms of] safety.” Those include Toshiba’s next-generation BWR, the “iB1350 (the innovative, intelligent and inexpensive Boiling Water Reactor 1350),” which features a passive safety system and accident tolerant fuel (ATF) utilizing silicon carbide cladding tubes. Irradiation testing of the ATF is planned in the United States in the current fiscal year.

In addition to expectations for early practical implementation, the WG members also demonstrated a keen interest in time spans and priorities in development, with an eye on carbon neutrality by 2050.

Concerning the matter of maintaining supply chains, TAMURA Tae, a senior analyst at Mizuho Bank, wanted to know what market share Japan could expect in the global advanced reactor market. She stressed the need to analyze the country’s competitiveness.

Another WG member, Professor TAKAKI Naoyuki of the Graduate School of Integrative Science and Engineering Cooperative Major in Nuclear Energy at Tokyo City University, who teaches nuclear technology, spoke about future human resources, saying that there were many students among the freshmen at his university’s orientation who expressed an interest in advanced nuclear reactors.

OHNO Kaoru, a manager at JAIF, said that the information given in explanations to the public should be presented in a manner easy to understand, in order to better ferment understanding. Such efforts, he said, would include referring to benefits in non-energy sectors such as medicine, opportunities for remote operation, and SDGs contributions.

Finally, in light of the recent Russian military invasion of Ukraine, concerns were expressed by the WG members about nuclear security and geopolitical risks, as well as the “need to consider international nuclear governance.”