At Kudankulam NPP in India, safety systems flushing into the exposed reactor has begun at Unit 3

At Kudankulam NPP in India (the Republic of India, the general designer and general contractor being the Rosatom State Corporation Engineering Division), the safety systems flushing into the exposed reactor began at Unit 3 on April 25, 2026. Samples of the flushing water have been collected and sent to a chemical laboratory for analysis.

The flushing is performed for post-installation cleaning of the emergency core cooling system pipeline; it is one of the key events in the unit commissioning to signify the beginning of the active commissioning phase.

The tests are conducted in several stages. During the first stage, the pressurizer and the first and second stage hydraulic accumulators are filled with water and then emptied into the reactor vessel, which is the passive part of the flushing operations. During the second stage, in the active part, the safety system pumps are filled with water from the spent fuel pool and then turned on, while the is being pumped into the open reactor. During the flushing operations, foreign objects that could enter the reactor vessel and damage its internal components during startup operations are removed from the pipelines connected to the primary circuit.

Prior to the flush, a number of necessary measures were completed, namely: voltage for the power unit’s auxiliary needs was energized; the production of demineralized water was organized; installation of process pipelines and equipment was completed; and the software and hardware systems responsible for monitoring and controlling the relevant equipment were put into operation.

“The flushing of the safety systems is the final stage before the reactor assembly. After this, tests of the primary circuit systems and equipment, cold and hot trial runs are beginning, Andrey Petrov, ASE JSC President pointed out. “Our joint project with our Indian partners is proceeding according to plan and proves the reliability and leadership of Russian nuclear technologies. The commissioning of the second and third stages of the Kudankulam NPP will make a significant contribution to India’s energy supply and further strengthen our long-standing mutual contacts”, he went on to say.

Bhuwan Chandra Pathak, Chairman and Managing Director of the Nuclear Power Corporation of India Ltd. (NPCIL) who was present at the key meeting, thanked the Russian side for its support and participation in the implementation of the project.

For reference:

The Kudankulam NPP Project is implemented as part of the Intergovernmental agreement on cooperation in the area of NPP construction in India, concluded on November 20, 1988, and the Addenda thereto of June 21, 1998.

Kudankulam NPP power units Nos. 1&2 were connected to the national grid of India in 2013 and 2016, respectively. They are the most powerful ones in India. They have generated during their operation (by April 2026) over 127 billion kWh of electricity.

Power units No. 3, 4, and 5 and 6 are the second and third stages of the Kudankulam NPP, each equipped with a VVER-1000 reactor. The technical solutions implemented in Kudankulam design characterize further evolutionary development of VVER-reactor NPPs of high power and transition to creation of a new, reliable, safe and feasible power unit.

After all six units have been put into operation, the Kudankulam NPP will cover a significant share of the electricity demands in Tamil Nadu, a 72 mln. state, as well as other states where the output will be distributed in accordance with the “South Grids of India” guidelines.

Rosatom State Corporation Engineering Division unites the leading companies of the nuclear industry, namely: Atomstroyexport JSC (Moscow, Nizhny Novgorod, branches in Russia and abroad), Joint Design Institute - Atomenergoproekt JSC (Moscow, Nizhny Novgorod, St. Petersburg branches - design institutes, branches in Russia and abroad, R&D branches) and subsidiary construction organizations. The Engineering Division ranks first in the world by the order portfolio and the number of NPPs constructed simultaneously across the world. About 80% of the Division’s revenues originate from foreign projects. The Engineering Division implements construction projects for high-power NPPs in Russia and across the world, renders a full range of EPC, EP, EPC(M) services including project management and design activities, and develops Multi-D technologies for the management of complex engineering facilities. The Division relies on the achievements of the Russian nuclear industry and modern cutting-edge technologies. www.ase-ec.ru<_http3a_ _www.ase-ec.ru2f_="">