China’s Tianwan 7 Reactor Reaches Minimum Controllable Power Level
Unit 7 of the Tianwan Nuclear Power Plant in China’s Jiangsu province reached its minimum controllable power level on Tuesday, the commissioning milestone at which a reactor’s core sustains a controlled chain reaction for the first time. The unit is China’s first VVER-1200, a Generation III+ pressurized-water design supplied by Russia’s Rosatom, and its startup follows fuel loading that began on August 12 with 163 fuel assemblies placed in the reactor core.
What minimum controllable power level actually shows
Reaching MCP is a narrower claim than starting commercial operation. At this stage, engineers confirm that the reactor’s control and protection systems respond correctly and that the core’s neutron-physical characteristics match design predictions, before power is raised in stages toward full output over the following weeks and months. Tianwan 7 is still scheduled to enter commercial operation later this year, with the identical Unit 8 following in 2027, and neither has yet been connected to the grid at full load.
A joint Russian-Chinese build
The plant is operated by Jiangsu Nuclear Power Corporation, a joint venture in which China National Nuclear Corporation holds 50%, China Power Investment Corporation 30% and Jiangsu Guoxin Group the remaining 20%. Rosatom’s engineering division supplied the VVER-1200 design and has overseen construction, continuing a nuclear relationship between Moscow and Beijing that has expanded even as Rosatom’s Western business has narrowed sharply since 2022. “The heart of the reactor at Unit 7 has begun beating,” Rosatom Director General Alexey Likhachev said, calling the milestone evidence of “the highest level of coordination and efficiency” between the two countries’ nuclear teams.
Tianwan’s growing role in China’s fleet
Tianwan’s earlier units mix Russian and Chinese technology: several of the site’s original reactors were built to Russian VVER-1000 designs, while two more recent units used domestic Chinese technology, making the complex one of the few sites in China with both import and indigenous reactor lines operating side by side. Once units 7 and 8 are both in commercial service, the plant’s combined installed capacity will exceed 9 GWe with annual generation above 70 TWh, placing Tianwan among the largest nuclear complexes anywhere. The VVER-1200 units add a newer reactor generation to that mix, with higher power output per unit and additional passive safety systems compared with the VVER-1000s that came before them at the same site.
Part of a broader Chinese build-out
The milestone lands as China continues to bring new nuclear capacity online faster than any other country, spanning both large pressurized-water reactors and domestic designs such as the Hualong One, whose third unit at Changjiang entered commercial operation earlier this year. For Rosatom, Tianwan 7 and 8 are among its most visible active projects, offering a marker of continued execution capacity even as the Russian state nuclear company deals with sanctions that have complicated some of its other export markets.
Sources
- World Nuclear News, “Tianwan 7 brought to minimum controllable power level,” September 29, 2026 — milestone date, reactor type, commissioning timeline, operator ownership structure, Rosatom Director General quote. world-nuclear-news.org
- Rosatom, statement by Director General Alexey Likhachev on Tianwan 7 startup, September 2026 — official confirmation and characterization of the milestone. rosatom.ru (via World Nuclear News)
- World Nuclear News, “Key commissioning tests completed at Tianwan 7,” 2026 — background on fuel loading date and pre-startup testing sequence. wnn.world-nuclear.org
Illustrative image. Photo: Nuclear Regulatory Commission, Public domain, via Wikimedia Commons — source
