Unit 1 at India's Kakrapar Atomic Power Station in western Gujarat state - a 220MWe Indian-design pressurised heavy water reactor (PHWR) -- shut down automatically on 13 March after a fault in a coolant system, according to the Atomic Energy Regulatory Board AERB) . "Safety systems have been provided for such incidents and those systems have worked," said AERB spokesman S Harikumar. Plant's operator Nuclear Power Corporation of India Ltd (NPCIL) said radiation levels within and outside the plant's premises are normal. The PHWRs at the Kakrapar NPP began operations in the mid-1990s. Over 350 employees and staff working in the reactor building were evacuated immediately following the leakage. An investigation is underway by expert teams from AERB and the Bhabha Atomic Research Centre (BARC).
Plant LK director Jain said, "The core cooling has continuously been maintained inside the plant with the help of shut-down cooling system and ECCS re-circulation system. We are also maintaining the coolant temperature up to 36 degrees. We are constantly monitoring the radiation levels inside and outside."
The Kakrapar plant comprises two 220 MWe PHWRs commissioned in September 1992 and January 1995 respectively. The second unit has been shut down since July 2015 for maintenance implying that now both units are under shut down.
Former AERB chief Dr A Gopalakrishanan said on 14 March that all future plans for expanding India's civilian nuclear power sector should be put on hold until a truly independent nuclear safety regulator is put in place, in view of the leakage. He said: "Department of Atomic Energy officials have no clue as to where exactly the leak is located and how big is the rate of irradiated heavy water that is leaking into the reactor containment. However, some reports indicate that the containment has been vented to the atmosphere at least once, if not more times, which I suspect indicates a gradual pressure build up in that closed containment space due to release of hot heavy water and steam into that containment housing. If this is true, the leak is not small, but moderately large."
He conjectured that one or more pressure tubes in the reactor (which contain the fuel bundles) have cracked open, leaking hot primary system heavy-water coolant into the containment housing. He said the seriousness of the accident and the potential high risks to the plant and personnel in the near vicinity are yet to be assessed. This is therefore an accident still in progress. His assessment is is based on bits and pieces of information gathered from different people close to the accident details and in positions of authority.
VK Gupta is spokesperson of All India Power Engineers' Federation, said a detailed evaluation may or may not prove Gopalakrishanan's conclusions or part of them to be well-founded. "But, technical experts are compelled to put out such conjectures because of the total lack of transparency of the Indian civilian nuclear power sector and the Atomic Energy Commission (AEC) and its associated agencies. AEC and its sub-ordinate organizations need to promptly release status reports on a progressing safety incident like the present one to the general public, to alleviate their concerns and anxieties."
