Chennai: India's atomic energy regulator found the pressure tubes and heavy water leakage warning-shutdown systems to be fine in all other pressurised heavy water reactors (PHWR) following the shut down of a Kakrapar Atomic Power Station (KAPS) unit, an official said.
The restarting of the power generation at the unit is up to the owner Nuclear Power Corporation of India Ltd (NPCIL) while the Atomic Energy Regulatory Board (AERB) has to be satisfied as to the cause of the leak and the safety measures. On the morning of March 11, the first reactor at KAPS shut down automatically following leakage of heavy water from its coolant channel. The leak was plugged ten days later.
"We studied the pressure tubes and leak detection systems in all other PHWRs in the country and found them to be satisfactory. We didn't find anything amiss in them that might result in an incident similar to that happened at Kakrapar," Shiv Abilash Bhardwaj, Chairman, Atomic Energy Regulatory Board (AERB) told IANS. According to NPCIL, 18 PHWRs are operated at different locations.
Bhardwaj said the non-destructive testing of the failed channel has been carried out at the Kakrapar unit 1 that was shut down due to heavy water leak. He said the ruptured coolant channel is yet to be removed. "Special tools have to be developed so that the evidence (the cause of rupture) is not disturbed while removing the affected channel," Bhardwaj remarked.
As the affected channel is in the reactor's core area, it has to be removed carefully due to radiation and transported to a lab. The affected channel needs radiation shielding. The equipments have to be brought in and set up for removing the affected channel.
"Both the units at KAPS are shut down. We are inspecting the coolant channel," S.K.Sharma, Chairman and Managing Director, NPCIL told IANS. India's atomic power plant operator NPCIL has two 220 MW units at KAPS. Following the heavy water leak, unit 1 is under cold shut down. The second unit is under maintenance shut-down since July 2015.