Flushing of safety systems begins for Kudankulam unit 3

Nuclear Power Corporation of India Limited (NPCIL) called it "a significant stride in India's journey towards energy security and sustainability".

The flushing process, using demineralised water, is designed to check everything has been installed correctly and remove impurities from pipelines, check pump sets, process safety systems and normal operation systems. Samples of flush water have been collected and sent to a chemical laboratory for analysis.

"During the second stage, the active part, the safety system pumps are filled with water from the used fuel pool and then activated, pumping water into the open reactor. During the flushing operations, foreign objects that could enter the reactor vessel and damage its internal components during startup are removed from the pipelines connected to the primary circuit," Rosatom said.

Andrey Petrov, President of JSC Atomstroyexport, said: "The safety system testing phase is the final stage before reactor assembly. After this, testing of the primary circuit systems and equipment, as well as cold and hot runs, will begin. Our joint project with our Indian partners is proceeding according to plan and confirms the reliability and leadership of Russian nuclear technology. The commissioning of the second and third phases of the Kudankulam NPP will be a significant contribution to India's energy supply and will further strengthen the long-standing ties between our countries."

Background

_{The Kudankulam site, about 100 kilometres from the port city of Tuticorin (Image: Rosatom)}

The Kudankulam site, near the southern tip of India, is already home to two operating Russian VVER-1000 pressurised water reactors which have been in commercial operation since 2014 (Kudankulam unit 1) and 2017 (unit 2). Four more are currently under construction, in two phases: construction of units 3 and 4 began in 2017, with work on units 5 and 6 beginning in 2021. Two further units - Kudankulam 7 and 8, larger AES-2006 units with VVER-1200 reactors - have been proposed as a fourth phase of the plant.

The first nuclear fuel was delivered for unit 3 in December under a contract signed in 2024 which covers the fuel supply for units 3 and 4 for the entire operating life of the units.