India needed heavy water in 1983 when 15 tons of the nuclear coolant vanished while being shipped from Norway to West Germany, government records show.

An official with access to the rec-ords said he did not know how India coped with the shortage. Another official at the Ministry of Science and Technology flatly denied that the missing Norwegian heavy water came to India.Both spoke on condition they not be further identified.

The Oslo newspaper Verdens Gang reported April 21 that 15 tons of heavy water was flown on a Liberian-registered West African airlines plane via Basel, Switzerland, to Dubai.

The paper said it then probably went to a nuclear reactor in Bombay.

The records show that five years ago, India needed to import heavy water to augment its own stock so it could commission a 235-megawatt, uranium-fueled reactor at Kalpakkam, 50 miles south of Madras in southern Tamil Nadu state.

The commissioning of the plant was to take place in 1982, but it was delayed for lack of heavy water, the official said.

The plant finally went into operation on Jan. 27, 1984, several months after the Norwegian consignment went astray.

The government official could not say where India got heavy water for the Kalpakkam plant.

Heavy water, or deuterium oxide, looks like ordinary water but has an extra neutron and cools a nuclear reactor by moderating the speed of neutrons released in a chain reaction.

It enables the reactor to run on natural uranium instead of enriched uranium fuel and to produce plutonium, which can be used for nuclear weapons.

India's nuclear power program has been based on natural uranium and heavy water.