Tianwan unit 6 enters commissioning phase

09 October 2020

Cold functional testing has been completed at unit 6 of the Tianwan nuclear power plant in China's Jiangsu province, China National Nuclear Corporation (CNNC) has announced. The ACPR1000 reactor is scheduled to enter commercial operation by the end of 2021.

A worker in the control room of Tianwan unit 6 (Image: CNNC)

Cold functional tests are carried out to confirm whether components and systems important to safety are properly installed and ready to operate in a cold condition. They are the first comprehensives tests to check the performance of the entire reactor. The main purpose of these tests is to verify the leak-tightness of the primary circuit and components - such as pressure vessels, pipelines and valves of both the nuclear and conventional islands - and to clean the main circulation pipes.

CNNC noted the completion of the tests on 4 October marks the transfer of Tianwan 6 from the equipment installation stage to the commissioning stage.

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 last month, with unit 6 expected to follow by the end of next year.

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, for which a general contract was signed in March.

When all eight units are in operation Tianwan would become the largest nuclear power plant in the world with eight units and a total generating capacity of about 8100 MWe.

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%).

Researched and written by World Nuclear News