By Masayuki Takata

Yomiuri Shimbun Senior Writer

Japanese heavy industrial company IHI Corp. is aiming to become a full participant in overseas projects to construct next-generation nuclear power devices known as small modular reactors (SMRs).

The company on Tuesday revealed to the media a full-size model of a structure that will become a part of a nuclear reactor building at a plant in Yokohama. Assembly of the model was completed earlier this month, after the company finished procuring components.

The model, for which IHI received the order in December 2024, was built for the purpose of testing welding techniques and planning construction schedules for a SMR construction project in Romania. The Romanian plant is scheduled to begin operating as early as 2030.

In regard to the Romanian project, the heavy industrial company aims to receive the order to manufacture real parts of the nuclear reactor building as well as a containment vessel. With that goal in mind, IHI plans to establish a system for creating the parts and the vessel by the end of 2027. Currently, there are limited prospects for the construction of new nuclear reactors in Japan, so IHI intends to maintain and improve its domestic human resources and technological foundation through overseas projects.

The model unveiled on Tuesday represents a set of four steel modules, pieces which will form part of the reactor building's wall. The model modules were combined to create a structure measuring 1.2 meters deep, 9 meters across and 6 meters high. The actual building, which will stand 50 meters tall, will require 620 modules.

The output of a single SMR is less than 300,000 kilowatts per unit, less than one-third of the output of recent commercial reactors, which can exceed 1 million kilowatts. However, SMRs have the advantage of allowing for flexible configuration, making it possible for a plant to have just one reactor or multiple.

In addition, equipment and components of SMRs are manufactured at factories before being assembled at the site of the nuclear power plant. This is expected to lower the risk of construction delays and cost overruns compared to the conventional construction method, in which equipment and components are manufactured on site.

In the case of the Romanian project, plans are being made to build the plant using SMR technology from U.S.-based NuScale Power Corp. It will comprise six pressurized water reactors which can produce 77,000 kilowatts of power each, for a total output of 462,000 kilowatts.

In Japan, restarting operations at existing commercial nuclear reactors has been prioritized over creating new reactors. At the Yokohama plant, Yasuyuki Hasegawa, an executive officer of IHI, spoke to the media about the company's future business plans. "We aim to maintain our technological capabilities by gaining experience overseas and eventually return to the domestic market," he said.

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This article is from The Yomiuri Shimbun. Dow Jones Newswires and The Wall Street Journal were not involved in the creation of this content.

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May 29, 2025 20:08 ET (00:08 GMT)

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