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In Japan, the country's largest nuclear plant is exporting power to the grid again. In South Korea, a new reactor reached full output the same season. In France, ministers have just cleared ground for two more. The bottleneck for compute is shifting from the chip to the baseload beneath it.
Kashiwazaki-Kariwa Unit 6 resumed commercial operation on 16 April 2026, after more than 14 years offline. The 1,315 megawatt reactor is the first Tokyo Electric Power Company (TEPCO) unit back since the 2011 Fukushima disaster. Japan drew just 8.5% of its electricity from nuclear in 2023. The restart is one step in a national reversal.
The reactors are coming back. The chipmakers were already waiting.
The opening is not the fab. It is the 1,315 MW reactor behind it
The story is usually told through silicon. It runs deeper than that. Kashiwazaki-Kariwa is the world's largest nuclear plant by capacity. Unit 6 is an advanced boiling water reactor (ABWR), offline since 2012. Its return took two false starts and about a 50-day delay. A monitoring alarm halted the first attempt in January. Commercial operation followed on 16 April. For TEPCO, it was the first restart since 2011. The machine matters more than the headline.
Japan's 7th plan lifts nuclear from 8.5% to 20% by 2040
The restart serves a plan, not a whim. Japan adopted its 7th Strategic Energy Plan in February 2025. The policy shifts nuclear from reduction to maximisation. It targets about 20% of electricity from nuclear by 2040, up from 8.5% in 2023. Renewables would supply 40 to 50%. Reaching the nuclear figure would need all 36 operable plants running. Only 12 run today. Analysts call the target a stretch. The direction, though, is set.
The clearest pairing: Tomari 3 restarts for Hokkaido's chip valley
One restart maps directly onto compute. Hokkaido Electric's Tomari Unit 3 met the regulator's safety requirements in 2025. The utility is targeting a 2027 restart, once a seawall is finished by March 2027. It names semiconductor and data centre demand as the reason. Rapidus is building a 2 nanometre chip fab at Chitose, on the same island. Its leaders call the cluster a Hokkaido Valley. The reactor and the fab share one grid. The link is explicit, not inferred. A worker died at the Tomari site on 18 August 2026, which may push the schedule back.
If your fab or data centre needs firm power this decade, what anchors the site?
Chip demand sites itself near power. Japan's data centres triple to 66 TWh
Compute now follows the megawatt. TSMC's factories in Kumamoto, on Kyushu, are Japan's flagship case. Wood Mackenzie expects Japanese data centre demand to triple to 66 terawatt-hours by 2034. Grid connections in Tokyo can take five to ten years. So projects move to Hokkaido and Kyushu, where land and power exist. Globally the pull is sharper still. Data centre electricity use rose 17% in 2025. Demand from AI-focused sites jumped by half. In Japan, data centres may reach 4 to 5% of peak demand by 2034. In the United States, the figure could hit 15%. The siting decision is now an energy decision.
South Korea confirms two reactors. Saeul 3 reaches commercial operation
The pattern repeats across the sea. South Korea confirmed two new large reactors under its 11th electricity plan. The plan lifts nuclear to 31.8% of power by 2030, and 35.6% by 2038. Saeul Unit 3 received its operating permit in December 2025. It reached first criticality in April 2026. Commercial operation is expected around August 2026, with Unit 4 to follow. Korea is not debating nuclear. It is building it.
Korea buys into US SMRs. KHNP takes a stake in TerraPower
Korea is also buying into the next generation abroad. Korea Hydro and Nuclear Power (KHNP) took a stake in TerraPower in January 2026. TerraPower is the US developer backed by Bill Gates. KHNP bought the stake from SK Innovation, which invested £188m ($250m, €220m) with SK Inc. in 2022. SK Innovation remains the second-largest shareholder. The purchase cleared the US foreign-investment review in December 2025. TerraPower's Natrium design is a 345 megawatt sodium-cooled reactor. Storage can lift its output to 500 megawatts on demand. A small modular reactor (SMR) is a compact, factory-built unit. The alliance ties Korean capital to American SMR supply.
The reactor twin: proving a restart before it runs
A restart is won on evidence, not assertion. Regulators demand a documented safety case before a reactor turns. Increasingly, operators lean on a reactor twin to support it. A reactor twin is the plant's digital copy, used for monitoring, simulation and licensing evidence. It lets an operator test a change before touching the plant. It gives a regulator a record to inspect. The value is not the model itself. It is the governed line from a standard to a decision. That discipline is what turns a paused asset back on.
Two cadences abroad: France's methodical EPR2, China's ten a year
Two other countries show contrasting tempos. France is committed to six next-generation European pressurised reactors (EPR2). EDF puts the programme cost at £62bn ($83bn, €73bn), with a final decision due by end 2026. In August 2026, the government authorised site work at Gravelines for two of them. The first is not expected until 2038. China moves on a different clock. It approved ten new reactors in 2025, a fourth straight year at that pace. About 30 units are under construction, near half the global total. That is an engineering fact, not a model to copy.
The investment implication: baseload is the new siting magnet
The capital lesson is simple. Firm, low-carbon baseload now pulls the most valuable industry toward it. A restarted reactor draws a fab. A fab draws the data centres around it. Land and permits still matter, but power decides. The risk sits with sites that assume grid supply arrives on time. In Tokyo, that assumption can cost five to ten years. Underwriting that prices the building, and not the megawatt beneath it, misreads the asset. The reactor, restarted or new, is the anchor.
The bottom line
The chipmakers were always going to wait for power. Now the power is arriving. Japan restarts its biggest reactor, Korea brings on Saeul 3, France breaks ground at Gravelines. Each move pulls compute toward firm supply. From Niigata to Chitose to Gravelines, the anchor is the same. Intelligence can map which sites clear first. The reactor still has to run.
Next week: Stargate UAE switches on its first 200 MW. The Gulf's AI-energy template goes live.
This analysis forms part of Vistergy's Technical Integration series, connecting energy, compute and infrastructure supply chains.
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