The reactor containment of KKNPP was hermetically sealed with steel liner inside the concrete wall and the dome.

Having successfully conducted ‘hot run’ in the second reactor, the Kudankulam Nuclear Power Project is waiting for Atomic Energy Regulatory Board’s nod for removing dummy fuel assemblies from the second unit and to load actual enriched uranium fuel assemblies.

After preparing the second 1,000-MWE VVER reactor, being built with Russian assistance, for the ‘hot run’, the KKNPP started the exercise on February 28 last. During this test, the second reactor, its associated closed primary coolant pipelines, secondary coolant circuits and the concrete reactor containment building demonstrated the strength and integrity prior to reactor start-up, KKNPP sources said.

The reactor’s inner containment building was tested at a pressure of 4.60 kg/sq. cm, though the actual pressure which would establish inside during power generation would be only 50 per cent of it. The reactor containment of KKNPP was hermetically sealed with steel liner inside the concrete wall and the dome. To ascertain the inadvertent presence of any microscopic holes in the containment, specially made soap solution was poured abundantly 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 bubble emission.

The reactor pressure vessel, the main coolant pipelines and every part of the reactor were tested by highly sophisticated robotic systems to ascertain whether these could withstand extreme factors as per the design specifications.

After an analysis by the Russian and KKNPP experts and the representatives of AERB at KKNPP complex, the data obtained during the ‘hot run’ and the subsequent inspections was forwarded to AERB’s headquarters in Mumbai for its final nod for removing the dummy fuel assemblies and loading 163 uranium fuel assemblies.

“If we can get AERB’s clearance in near future, we will be able to complete actual fuel loading by June and the reactor will be ready for criticality before July-end,” the sources said.