Welding of circumferential seams on the upper half of the reactor vessel for unit 7 of the Tianwan nuclear power plant has begun, Russia's Atommash has announced.
The company said this was a key milestone in the manufacturing of the reactor which will be the seventh at the Tianwan nuclear power plant, in Jiangsu province in China.
"The upper half of the vessel has been put together from two shells and a flange and weighs a total of 180 tonnes," Atommash said.
Workers have "begun the automatic welding process of the two circumferential seams using specialised equipment. The operation will last for 25 days with continuous heating of the weld zone. A total of 5000 kg of flux and 3500 kg of wire will be used during the welding process," it added.
"Once this operation is complete, the seams will be heated up to 300 degrees and transferred to a heat treatment furnace. The heating and holding process takes place at a maximum temperature of 620 degrees for three days."
In 2018 China and Russia signed agreements for the construction of Tianwan units 7 and 8, with VVER-1200 reactors designed and managed by Rosatom’s engineering division.