Tianwan 7 nuclear reactor connects to China's grid

Overview

Updated Oct 25

China's nuclear safety regulator cleared the Tianwan 7 reactor to push past 25% of its rated thermal output on October 16, after a four-day inspection. The Russian-built VVER-1200 unit first sent electricity to the grid on October 8.

The National Nuclear Safety Administration told operator Jiangsu Nuclear Power Company to fix a rod-position display fault found in a control-rod test before output rises beyond the 25% plateau, and to assess several equipment defects. Power is due to climb toward 50% for final performance tests, with commercial operation targeted before year-end.

Why it matters

When all eight Tianwan units run, the base generates over 70 billion kWh a year, displacing fossil power in China's eastern grid.

Questions about this story

Free account needed to ask — your question is kept and asked for you right after sign-up. Answers are public.

No questions yet — be the first to ask.

Key Indicators

~10 billion kWh

Unit 7 annual generation

Expected yearly output from the VVER-1200 reactor, per CNNC estimates.

9+ GWe

Total plant capacity when complete

Combined capacity of all eight Tianwan units after 7 and 8 reach commercial operation.

57.4M tonnes

Annual CO2 avoided at full buildout

Carbon dioxide emissions expected to be cut each year once all eight units run.

550+ billion kWh

Cumulative output from units 1-6

Electricity delivered by units 1-6 since 2007, per Xinhua; China Energy News cites more than 500 billion kWh.

25%

Power threshold cleared by regulator

Share of rated thermal output that unit 7 is now permitted to exceed, after the October 16 sign-off.

Voices

Curated perspectives — historical figures and your fellow readers.

People Involved

Zhang Yi

Chairman, Jiangsu Nuclear Power Corporation

Announced unit 7 grid connection; expects commercial operation within 2026

Alexey Likhachev

Director General, Rosatom

Overseeing VVER-1200 supply to China

Xi Jinping

President of China

Witnessed 2021 groundbreaking for Tianwan 7-8

Organizations Involved

China National Nuclear Corporation (CNNC)

State-owned nuclear corporation

Majority owner of Jiangsu Nuclear Power Company and lead Chinese partner

China's state nuclear corporation and 50% owner of the Jiangsu Nuclear Power Company joint venture running Tianwan.

Jiangsu Nuclear Power Company

Joint venture

Cleared on October 16 to raise unit 7 above 25% power, with four inspection findings to close

Joint venture operating the Tianwan plant, held by CNNC (50%), China Power Investment Corporation (30%), and Jiangsu Guoxin Group (20%).

Rosatom

State-owned nuclear corporation

Designer and builder of Tianwan units 7-8

Russia's state nuclear corporation, designer and supplier of the VVER-1200 reactors at Tianwan 7-8 and Xudabao 3-4.

Timeline

June 2018 October 2026

11 events Latest: October 16th, 2026 · 4 weeks ago Showing 8 of 11

Tap a bar to jump to that date

October 2026
Regulator clears unit 7 to pass 25% power
Latest Regulatory

National Nuclear Safety Administration released the reactor from its 25% rated thermal power control point after an October 11-14 inspection, with four fixes to close before output rises further.
October 16th, 2026
Tianwan 7 connects to the grid
Milestone

VVER-1200 delivers first electricity; commissioning tests continue toward commercial operation.
October 8th, 2026
Cold tests complete at unit 8
Testing

Primary circuit leak-tightness verified on the sister unit.
October 2026
September 2026
Unit 7 reaches criticality
Milestone

Reactor achieves a self-sustaining chain reaction at minimum controllable power.
September 2026
August 2026
Fuel loading begins at unit 7
Testing

Loading of 163 fuel assemblies begins; all fuel in the core by August 18.
August 12th, 2026
December 2025
Hot tests complete at unit 7
Testing

Systems simulate normal operating temperatures and pressures.
December 30th, 2025
July 2025
Cold tests complete at unit 7
Testing

Primary circuit leak-tightness verified, moving the unit from installation to commissioning.
July 2025
February 2022
Construction begins on unit 8
Construction

Sister reactor starts, scheduled for commercial operation in 2027.
February 2022
May 2021
Xi and Putin open construction via video link
Diplomatic

Presidents witness the groundbreaking for Tianwan 7-8 and Xudabao 3-4 remotely.
May 19th, 2021
Construction begins on unit 7
Construction

First concrete for the VVER-1200 reactor at the Jiangsu site.
May 2021
June 2018
Russia and China sign Tianwan 7-8 agreements
Agreement

Moscow and Beijing agree to build two VVER-1200 reactors as Tianwan units 7 and 8.
June 2018

#timeline [x-show="expanded"] { display: revert !important; opacity: 1 !important; } #timeline .timeline-toggle-btn { display: none; }

Scenarios

Tianwan 7 Reaches Commercial Operation Before Year-End

Likely Resolves by Jan 31, 2027

Discussed by: Jiangsu Nuclear Power chairman Zhang Yi; World Nuclear News

Unit 7 moves through staged power ascension, with tests and checks at each level before advancing. CNNC says the unit will verify performance under commercial operating conditions in the coming weeks. Zhang Yi expects the formal commercial operation declaration before the end of 2026.

Tianwan 8 Connects to Grid in 2027

Possible Resolves by End of 2027

Discussed by: Rosatom; the original 2018 schedule

Unit 8 began construction in February 2022, about a year behind unit 7, with commercial operation penciled in for 2027. Cold tests finished in October 2026, leaving hot tests, fuel loading, and startup ahead. If it mirrors unit 7's pace, grid connection lands in late 2027.

Full 8-Unit Base Exceeds 9 GWe

Possible Resolves by Q2 2028

Discussed by: CNNC planning statements

With all eight units in commercial operation, the base tops 9 GWe of installed capacity, generates over 70 billion kWh per year, and cuts 57.4 million tonnes of CO2 annually. The milestone closes out the two-decade Sino-Russian Tianwan program and makes the site one of China's largest nuclear stations.

Inspection Findings Push Tianwan 7 Startup Into 2027

Possible Resolves by End of 2026

Discussed by: National Nuclear Safety Administration inspection report

The regulator tied further power increases to fixing the rod-position display fault, assessing current equipment defects, re-checking a probabilistic risk threshold and tightening test-report quality. If the repairs and the East China regional office's confirmation take longer than expected, commercial operation slips past the year-end target.

Historical Context

2 moments from history that rhyme with this story — and how they unfolded.

June 2007 - December 2018

Tianwan units 1-4 (2007-2018)

Russia supplied the first four Tianwan units, Gidropress VVER reactors that entered commercial operation between June 2007 and December 2018. Units 1-2 have run for two decades and units 3-4 for close to a decade, per Rosatom chief Alexey Likhachev.

Then

Established a working delivery model for Russian reactors in China and a track record of reliable operation.

Now

Paved the way for the 2018 agreement on units 7-8 and the parallel Xudabao 3-4 project.

Why this matters now

The same Russian design lineage and cooperation structure now carry units 7-8.

May 2021 - present

Xudabao units 3-4 (2021-)

The same June 2018 agreement covered two more VVER-1200s at Xudabao in Liaoning province. Construction began alongside Tianwan 7-8 with the same groundbreaking ceremony witnessed by Xi Jinping and Vladimir Putin.

Then

Will show whether the Tianwan construction and commissioning pace is repeatable at a second site.

Now

Doubles the Sino-Russian VVER-1200 program to four reactors across two locations.

Why this matters now

Xudabao is the parallel test of the model Tianwan 7 now demonstrates.