The containment dome of unit 6 of the Tianwan nuclear power plant in China's Jiangsu province was installed on 5 May, marking the reactor's entry into the equipment installation phase of construction, China Nuclear Engineering and Construction Corporation (CNECC) announced today. CNECC is a subsidiary of China National Nuclear Corporation (CNNC).

Installation of the containment dome at Tianwan 6 (Image: CNECC)

Installation of the 148-tonne dome was completed at 3:49pm on 5 May and completes the civil construction phase of the project. The operation to lift the dome 60 meters above ground level and to lower it into place on top of the walls of the containment building took 53 minutes to complete, CNECC said.

Construction of Tianwan Phase III - units 5 and 6 - was originally scheduled to start in early 2011. However, following the March 2011 accident at Japan's Fukushima Daiichi plant, the Chinese government suspended the approval of new nuclear power projects, including those two units.

The latest Five-Year Plan called for construction of Phase III of the Tianwan plant to be accelerated. China's State Council gave its approval for Tianwan units 5 and 6 - both featuring 1080 MWe ACPR1000 reactors - on 16 December 2015. First safety-related concrete was poured for unit 5 on 27 December 2015, with that for unit 6 poured on 7 September 2016.

CNNC plans to put both units 5 and 6 into commercial operation by the end of 2021.

Tianwan Phase I - units 1 and 2 - was constructed under a 1992 cooperation agreement between China and Russia. First concrete was poured in October 1999, and the units were commissioned in June 2007 and September 2007 respectively. Tianwan Phase II - units 3 and 4 - are similar to the first stage of the Tianwan plant, comprising two Russian-designed 1060 MWe VVER-1000 pressurised water reactors. First concrete for unit 3 was poured in December 2012, while construction of the fourth unit began in September 2013. Unit 3 achieved first criticality on 29 September last year and was connected to the grid on 30 December. The unit completed demonstration operation at nominal capacity for 100 hours on 15 February and is scheduled to enter commercial operation later this year. Unit 4 is expected to begin operating in March 2019.

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%).