The loading of fuel assemblies into the core of the reactor of unit 6 at the Tianwan nuclear power plant in China's Jiangsu province began on 14 April, China National Nuclear Corporation (CNNC) has announced. The domestically-designed ACPR1000 reactor is scheduled to enter commercial operation by the end of this year.

"The loading marks the moment that unit 6 enters its nuclear commissioning stage, and is a key step towards the completion of the Tianwan Phase III Project," CNNC said. "It is also a key step that is required before grid-connected power generation."

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.

Hot functional testing of Tianwan 6 began on 28 November. These tests involved increasing the temperature of the reactor coolant system and carrying out comprehensive tests to ensure that coolant circuits and safety systems are operating as they should. Carried out before the loading of nuclear fuel, such testing simulates the thermal working conditions of the power plant and verifies that nuclear island and conventional equipment and systems meet design requirements. These tests were completed on 29 December.

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 2020.

According to CNNC, the five units in commercial operation at Tianwan have to date generated more than 260 terawatt-hours of electricity. This, it said, is equivalent to reducing standard coal consumption by 80 million tonnes, cutting carbon dioxide emissions by 200 million tonnes, or planting 870,000 hectares of trees.

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%).