The largest and heaviest module has been installed at unit 3 of the Sanmen nuclear power plant in China's Zhejiang province, China National Nuclear Corporation (CNNC) has announced.

The CA20 module prior to its hoisting into position in the nuclear island of Sanmen 3 (Image: CNNC)

The cuboid-shaped CA20 module comprises plant and equipment for used fuel storage, transmission, the heat exchanger and waste collection, among other things. The module measures 20.5 metres long, 14.1 metres wide and 20.9 metres high.

At 7.36am on 16 August, after a series of hoisting operations, the CA20 module of the unit was moved into place, the company said. The total weight of the hoisting was more than 1000 tonnes, and it was carried out using a 2600-tonne crawler crane.

Over 1800 cubic yards (1376 cubic metres) of concrete will now be poured to fill the walls of the CA20 module.

The CA20 module in position at Sanmen 3 (Image: CNNC)

The CAP1000 reactor design - the Chinese version of the AP1000 - uses modular construction techniques, enabling large structural modules to be built at factories and then installed at the site. This means that more construction activities can take place at the same time, reducing the time taken to build a plant as well as offering economic and quality control benefits.

The construction of two new reactors at each of the Sanmen, Haiyang and Lufeng nuclear power plant sites in China was approved by the country's State Council on 20 April this year. The approvals were for Sanmen units 3 and 4, Haiyang 3 and 4 and units 5 and 6 of the Lufeng plant.

The Sanmen and Haiyang plants are already home to two Westinghouse AP1000 units each, and two CAP1000 units were approved for Phase II (units 3 and 4) of each plant.

In May, CNNC signed contracts for the civil construction of the nuclear islands and installation engineering for the planned second phases of the Sanmen and Haiyang nuclear power plants. China Nuclear Industry 22 Construction Company was contracted to carry out the civil construction of the Sanmen Phase II nuclear island, while China Nuclear Industry 24 Construction Company will conduct the civil construction of the Haiyang Phase II nuclear island. Meanwhile, China Nuclear Industry Fifth Construction Company (CNI5) has been contracted to undertake the nuclear island installation work at all four units.

The first safety-related concrete was poured for the nuclear island of Sanmen 3 on 28 June, marking the official start of its construction.

Phase I of the Sanmen plant began operating in 2018. Sanmen 1 was the world's first AP1000 to start up, achieving first criticality - a sustained chain reaction - on 22 June and grid connection on 2 July. It reached full power operation for the first time on 14 August and entered commercial operation on 21 September. Sanmen 2 attained first criticality on 17 August and was connected to the grid on 24 August. The reactor entered commercial operation on 5 November.

Researched and written by World Nuclear News

Date: Thursday, 18 August 2022
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