Unit 6 of the Tianwan nuclear power plant in China's Jiangsu province has entered commercial operation, having successfully completed a 100-hour continuous operation test run at full power. Tianwan 6 becomes China National Nuclear Corporation's (CNNC) 24th reactor in commercial operation, increasing the company's installed generating capacity from 21.391 GWe to 22.509 GWe (gross).

The 1080 MWe (net) domestically-designed ACPR1000 pressurised water reactor was connected to the electricity grid on 11 May. Since then, the unit has undergone tests at 30%, 50% and 100% of its generating capacity before entering a full-power demonstration operating assessment. Tianwan 6 completed the full-power test run at 10.06pm yesterday, CNNC announced today.

Units 5 and 6 at Tianwan - Tianwan Phase III - both feature ACPR1000 reactors. First safety-related concrete was poured for unit 5 on 27 December 2015, with that for unit 6 poured on 7 September 2016. Tianwan 5 entered commercial operation in September last year.

According to CNNC, the output from the two units of Tianwan Phase III will avoid the burning of 5.17 million tonnes of standard coal per year, cutting CO2 emissions by 13.6 million tonnes and sulphur dioxide emissions by 44,100 tonnes. This, it says, is equivalent to planting 34,000 hectares of trees.

The first four units at the site - which began commercial operation between June 2007 and December 2018 - are Gidropress VVER units supplied by Russia, as will be the seventh and eighth.

In March 2020, a general contract for Phase IV - units 7 and 8 - of the Tianwan plant was signed between AtomStroyExport, the engineering division of Russian state nuclear corporation Rosatom, and CNNC. The first concrete was poured for Tianwan unit 7 on 19 May this year. Units 7 and 8 are scheduled to be commissioned in 2026-2027.

The Tianwan plant is owned and operated by Jiangsu Nuclear Power Corporation, a joint venture between CNNC (50%), China Power Investment Corporation (30%) and Jiangsu Guoxin Group (20%).