A rendering of a new type of nuclear reactor to be developed by Mitsubishi Heavy Industries Ltd. with four major Japanese utilities. (Courtesy of Mitsubishi Heavy Industries

September 29, 2022

TOKYO (Kyodo) — Mitsubishi Heavy Industries Ltd. and a subsidiary of Hitachi Ltd. will separately develop next-generation nuclear reactors in what could be the first two projects in the government’s recent policy shift to push nuclear energy.

Mitsubishi Heavy said Thursday it will develop with four major Japanese utilities an advanced light-water reactor, a new type of pressurized water reactor, or PWR, deemed safer than existing models, and plan to put it into use in the mid-2030s.

The four power companies — Kansai Electric Power Co., Hokkaido Electric Power Co., Shikoku Electric Power Co. and Kyushu Electric Power Co. — all operate Mitsubishi Heavy reactors at their nuclear plants.

The new reactor, called SRZ-1200, is designed to be more resilient to natural disasters, such as tsunamis and earthquakes, as well as terrorist attacks, Mitsubishi said.

The facility, with an output of about 1.2 million kilowatts, will also enhance equipment to seal off melted nuclear fuel in a containment vessel and prevent or limit radiation leaks in the event of an accident.

Hitachi-GE Nuclear Energy Ltd., a Hitachi subsidiary, will also develop an advanced nuclear reactor based on light-water reactor technology for use in the mid-2030s, a person familiar with the matter said Thursday. Hitachi has an 80.01 percent stake in the subsidiary, with the rest owned by General Electric Co.

These plans come as the Japanese government announced in August that it would promote the construction of next-generation nuclear power plants to ensure a stable electricity supply without producing carbon dioxide emissions, in a major reversal from its policy of no new nuclear energy.

Among a variety of next-generation nuclear reactor types, the government plans to prioritize developing advanced light-water reactors as it could utilize existing supply chains, given the technological similarities to PWRs.

Chief Cabinet Secretary Hirokazu Matsuno welcomed the news of Mitsubishi Heavy’s project, saying at a press conference, “I hope relevant ministries will consider (helping the development of) next-generation reactors based on research and development activities like this.”

Concerns over the safety of nuclear power generation remain strong in Japan after a massive earthquake and tsunami caused the nuclear crisis at the Fukushima Daiichi plant in 2011 — the world’s worst nuclear disaster since Chernobyl in 1986.

Such safety concerns prompted the government to shelve the construction of new nuclear reactors, even as Japanese nuclear regulators set stricter safety regulations after the Fukushima disaster.

https://mainichi.jp/english/articles/20220929/p2g/00m/0bu/053000c