Main coolant pipeline for third atomic power plant at Kudankulam completed

The welding of the main coolant pipeline at the upcoming third 1,000 MW atomic power plant at Tamil Nadu's Kudankulam got completed early this month, Russia’s integrated nuclear power major Rosatom said on Friday.

According to Rosatom, the welding of the main coolant pipeline which began in December 2022, was completed on August 5.

The main coolant pipeline combines the main equipment of the primary circuit, including the reactor, the steam generators, and the reactor coolant pumps. Considering high requirements for quality and operational conditions, the main coolant pipeline welding is one of the most complicated and important stages of civil and erection works at the power unit.

"It is the reactor coolant pipeline that carries the water heated in the reactor into the steam generators from which the generated steam goes into the turbine steam path, and the turbine generator generates electricity," Rosatom said.

The Russian company said the main coolant pipeline has a total length of about 140 m, the thickness of the pipe walls is 70 mm, and the total length of 28 welded joints is more than 87 m. Its design service life is 60 years in a tough environment.

During the welding of the main coolant pipeline which began in December 2022, a technology proposed by the Russian party was used, which made it possible for the Nuclear Power Corporation of India Ltd (NPCIL) to reduce the operation time from 270 to 219 days.

Upon completion of the main coolant pipeline welding, "flushing with the open reactor" operations and the "hydraulic tests and circulation flushing of the primary circuit" stage will start, Rosatom added.

India's atomic power plant operator NPCIL has two functional 1,000 MW plants (Units 1 and 2) at Kudankulam, while four more (Units 3, 4, 5 and 6) are under construction. All the six units are built with Russian technology and equipment supplied by Rosatom.

Major equipment for building the third and fourth units have reached Kudankulam from Russia, while a sizable number of components for the fifth and sixth units are to come.