Responding to supplementaries in the Lok Sabha during Question Hour, Minister of State in Prime Minister's Office Jitendra Singh said the leakage, which occured four days ago, was an "incident" and not an "accident".
To keep the temperature down, alternative systems came into play when the coolant pipe leaked, he said.
The minister said that on a scale of one to ten, as per the standards laid down by the international comminity, the incident was of Grade One.
Referring to the nuclear liability law, he said India has assured that the interest of the victim in cases of an accident remains paramount. He said contrary to "speculation", the onus remains on the supplier in cases of an accident.
He said at present the share of nuclear power in total electricity generation in the country was about 3.3 per cent and added that more power reactors are planned in future.