The welding of the main circulation pipeline has started for Unit 2 of the Sanaocun nuclear power station in the eastern Chinese province of Zhejiang, according to the China Nuclear Energy Association (CNEA).

Sanaocun, also known as Zhejiang Sanao (San’ao), has two domestic 1,117-MW Hualong One units under construction – Sanaocun-1 since December 2020 and Sanaocun-2 a year later.

The pipeline connects the reactor pressure vessel with the steam generators and the reactor coolant pumps and its welding is usually seen as a milestone development for nuclear new-build projects.

The Hualong One, or HPR1000, is an indigenous pressurised water reactor unit that incorporates elements of CNNC’s ACP1000 and China General Nuclear’s ACPR1000+ reactor designs.

China has 14 Hualong One units under construction domestically at eight sites – one unit each at Ningde, Shidaowan and Fangchenggang; two units each at Changjiang, Lufeng, Taipingling, Sanaocun and Jinqimen; and three units at Zhangzhou.

The country has the most rapidly expanding nuclear fleet in the world, according to data by the International Atomic Energy Agency.