Nuclear power stocks,
across all of Japan.

According to the Japan Atomic Industrial Forum's news site, the government will publish, within this fiscal year, how many workers it needs to replace Japan's nuclear plants. On July 31, a ministerial meeting adopted guidelines that expect replacements equal to two to five large reactors by the 2040s and 11 to 14 by the 2050s. On October 7, an industry, academia and government consortium to secure and train nuclear workers was launched. Abroad, Mitsubishi Heavy Industries delivered three replacement steam generators to a plant of Électricité de France (EDF) on October 15. It has won nine from EDF in total and will deliver the remaining six from 2028.

Nuclear work already shows in Japanese earnings. Tokyo Energy & Systems grew orders on safety upgrades for reactor restarts and other work, lifting its order backlog to a record ¥144.9 billion. Taihei Dengyo grew orders in its construction segment 65.7% on more nuclear plant work.

• Source：Government to publish the workforce needed to replace nuclear plants (Japan Atomic Industrial Forum, October 19, 2026, in Japanese)
• Source：Nuclear plant replacement target formally adopted (Japan Atomic Industrial Forum, August 3, 2026, in Japanese)
• Source：MHI delivers three steam generators to EDF (Japan Atomic Industrial Forum, October 16, 2026, in Japanese)

Nuclear stocks bring to mind the construction of new reactors. But the replacements the government expects, two to five large reactors by the 2040s, are still plans.

The money moving at Japan's plants today should instead be safety upgrades to restart idle reactors, plus periodic inspections and part replacements at running ones. Even the steam generators Mitsubishi Heavy Industries delivered to EDF were replacement parts to keep old reactors running longer.

So we used Katana to search annual reports for companies whose core business is nuclear products, work or services, and checked what they earn from.

All 7 companies whose nuclear revenue we could confirm in their reports earn from restarts, maintenance and decommissioning. None reported sales from new reactors in Japan. The surprise was decommissioning: Tokyo Energy & Systems, Okano Valve, Kimura Chemical Plants and Liberaware all name Fukushima Daiichi decommissioning among their sales or orders. Even Mitsubishi Heavy Industries says its nuclear orders grew on nuclear fuel cycle work, such as the Rokkasho reprocessing plant.

New builds in Japan are still at the survey and design stage. TVE's report notes that in July 2025, Kansai Electric Power announced it would resume site surveys at its Mihama plant to consider a successor to Unit 1. In July 2026, Japan passed an amended Electricity Business Act allowing public loans for replacing nuclear plants. In August, Mitsubishi Heavy Industries won three projects under a trade ministry support program, including the SRZ-1200 advanced light water reactor and a small light water reactor based on Japanese technology.

Abroad, new builds are getting under way. The BWRX-300, a small modular reactor (SMR, a small reactor assembled from factory-built parts) that Hitachi develops with GE Vernova, is under construction in Canada, and in September 2026 a U.S. Tennessee Valley Authority project received a construction permit. A U.S.-Japan investment deal in March listed BWRX-300 projects in Tennessee and Alabama worth up to $40 billion. In components, Japan Steel Works plans to double its capacity for nuclear products by the year ending March 2029, expecting large reactor projects in Europe and the U.S. In March, IHI signed a memorandum with X-energy, which has a 144-unit orderbook, to explore working on pressure vessels and other parts for its high-temperature gas reactor. The only company to report a new-build order amount is Toyo Tanso, which won ¥2.4 billion in graphite for X-energy. The main companies:

Even companies named as new-reactor stocks earn today from restarts and maintenance, or from projects abroad. The replacements the government expects in Japan come to two to five large reactors by the 2040s, and new-build demand is arriving from abroad first.

• Source：Amended Electricity Business Act passed, allowing public loans for nuclear replacements (Nikkei, July 17, 2026, in Japanese)
• Source：Three MHI proposals selected for a METI next-generation reactor support program (Mitsubishi Heavy Industries, August 5, 2026, in Japanese)
• Source：NRC Construction Permit to TVA for BWRX-300 (Neutron Bytes, September 30, 2026)
• Source：New U.S. BWRX-300 projects get Japanese investment (ANS Nuclear Newswire, March 25, 2026)
• Source：JSW Muroran to double capacity for nuclear products (Hokkaido Shimbun, July 13, 2026, in Japanese)
• Source：X-energy, IHI to explore collaboration (World Nuclear News, March 18, 2026)