Koodankulam Nuclear Power Project's first of the 2 X 1,000 MWe reactors, which is likely to attain criticality in March this year, has successfully crossed the landmark milestone – Integrity Test of Reactor Containment – on the eve of Republic Day.

Prior to the reactor start-up, it is required to demonstrate the strength and integrity of the reactor and its associated closed primary coolant pipelines, secondary coolant circuits as well as the concrete reactor containment building completely. The integrity test was started on January 16 after meticulous prior arrangements such as completion of all construction works related to the containment and simulation of operating condition of the reactor plant.

The reactor inner containment building, which is 44 meter in diameter and around 67 meter high, was tested at a pressure of 4.60 kg/sq. cm. though the actual pressure which would establish inside the containment during power generation would be only 50 per cent of it.

The reactor containment of KKNPP is hermetically sealed with steel liner inside the concrete wall and the dome. The inner containment wall of the reactor building is of 1.20 meter thick with a pre-stressed concrete construction.

“Since it is a 1,000 MWe reactor, we did these tests at much higher pressure,” an elated Site Director, KKNPP, M. Kasinath Balaji told reporters at Koodankulam on Thursday.

“The successful completion of the tests has established the strength and structural integrity of the building which houses the nuclear reactor. Moreover, this achievement has showcased the technical expertise of Nuclear Power Corporation of India Limited scientists in dealing with 1,000 MWe VVER reactors being supplied by Russia and our technocrats' ability to assimilate such complicated technology at such a faster rate.”

To ascertain the inadvertent presence of any microscopic holes in the containment, specially made soap solution was poured abundantly and continuously from the top even as pressure was phenomenally mounting inside and a large number of personnel were posted at various points to closely look for emitting bubbles, if any.

Other significant milestone of hydraulic testing of the primary and secondary circuits of the Nuclear Steam Supply System was also successfully carried out. The hydraulic testing of the entire system including the equipment, piping, tubing and supporting system were successfully tested at a pressure much higher than the normal operating pressure to establish the strength and leak tightness of the circuit.

The primary circuit which underwent hydraulic testing included reactor pressure vessel, steam generators, reactor coolant pumps and associated reactor process and safety system equipment. The entire erection and welding of equipment, piping and tubing were carried out by the NPCIL engineers and technicians from Indian industry.

“All these tests were carried out in the presence of specialists from NPCIL, Atomic Energy Regulatory Board and Russian design organisations. The tests were closely monitored and data collected using highly accurate, sensitive and modern instrumentation. The completion of the tests has paved the way for the ‘Hot Run' of the reactor with dummy fuel for conducting process tests of the reactor plant, which will be followed by the (actual) fuel loading for the start-up of the reactor and electricity generation,” Mr. Kasinath Balaji noted.

The second rector, which has reached advanced stage of erection, is expected to attain criticality before December-end. Meanwhile, the Union Government, negotiating with their Russian counterparts on the techno – commercial aspects of reactors 3 and 4, is likely to give its nod for ‘First Pour of Concrete' for these reactors anytime after May or June this year.

While asserting that the reactors have been provided with futuristic safety features, Mr. Kasinath Balaji said the State Government officials would soon be trained thoroughly to deal with any urgent situation or in case of any crisis and a detailed literature on dealing with such situations would be distributed.

“In fact, a comprehensive rehearsal will be conducted very soon,” he said.

Project Director (3rd and 4th reactors), KKNPP, R. Banerjee, Site Director (Units 1 and 2) R.S. Sundar, Chief Construction Engineer B.C. Pathak, Chief Engineer (Engineering and Utility) S.V. Jinnah, Additional Chief Engineer (Unit 1) Suresh were present.

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