The Yomiuri Shimbun

The Japanese and British governments are poised to agree on the joint research and development of high-temperature gas-cooled reactors (HTGRs) during a summit in London on Sunday, it has been learned.

Targeting the early 2030s for a demonstration reactor in Britain, the public and private sectors from both nations are likely to collaborate on a framework that will allow Japan to later use the technology domestically.

HTGRs are expected to be among the points of discussion when Japanese Prime Minister Sanae Takaichi and British Prime Minister Keir Starmer meet on Sunday. The Japan Atomic Energy Agency, the United Kingdom National Nuclear Laboratory and British heavy machinery giant Rolls-Royce PLC are set to sign a memorandum of cooperation to pool their expertise in developing HTGRs and fuel.

An HTGR is a next-generation nuclear reactor that uses helium gas to extract heat generated from nuclear fuel in the reactor's core. The reactor can both generate electricity and harness its high temperature for hydrogen production.

Hydrogen is viewed as a key source of green energy because it is a zero-emission fuel that releases no carbon dioxide.

The reactor is considered highly resistant to meltdowns because its core, where fuel is located, can withstand extreme temperatures and the fuel itself is covered with extremely heat-resistant materials.

Experts have pointed out the reactor's superior safety, noting that the absence of water in the core rules out the possibility, in principle, of a hydrogen explosion.

Japan's involvement in HTGR development dates to the 1960s, with the nation building a solid track record through an experimental reactor that paved the way for a demonstration model.

Meanwhile, Britain has taken the lead in the regulatory steps toward building a demonstration reactor, with the government having unveiled a supportive policy framework for next-generation nuclear projects in February.

In recent years, nations including the United States, China and South Korea have also ramped up their development efforts, steadily advancing their technological capabilities.

At the summit, the Japanese and British governments are expected to sign a pact on economic security and advanced technology, with HTGRs serving as a key area of practical cooperation.

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This article is from The Yomiuri Shimbun. Neither Dow Jones Newswires, MarketWatch, Barron's nor The Wall Street Journal were involved in the creation of this content.

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June 12, 2026 08:32 ET (12:32 GMT)

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