Bangalore, Aug 13 - India's nuclear submarine INS Arihant, launched on July 26, does not have a 'working nuclear reactor' yet, says a nuclear scientist familiar with the project almost since its start.

'If any of you are under the impression that it made contact with water with an actual reactor fitted inside its hull you are mistaken,' the scientist told IANS.

The scientist echoes a report in Defence Professionals Daily, a German online publication, which says Arihant 'currently is little more than a floating hull' without nuclear propulsion or weapons systems. The scientist, who did not want to be named as he was not authorised to speak to the media, was clarifying media reports implying that Arihant is propelled by nuclear power and that India has become the sixth nation to operate nuclear subs.

'I think the media did not correctly report what was told to them by the Bhabha Atomic Research Centre (BARC), or the officials deliberately did not want to be explicit beyond a point,' he said.

The reports had said that Arihant is fitted with a nuclear power plant that is a replica of the secretly built 80-MW reactor at Kalpakkam near Chennai that was shown to the media Aug 2.

Building this land-based power plant -- for demonstration and training the naval personnel -- is no doubt a creditable achievement of BARC considering that 'making the fuel tubes were a real challenge', the source said.

Besides, he said, it has proved India's ability to produce enriched uranium necessary for designing small enough reactors that can fit inside the submarine.

The higher the enrichment, the smaller the size of the reactor and, according to the source, the Indian design uses 15 to 20 percent enrichment. The commercial Tarapur nuclear power plant, on the other hand, uses about three percent enriched imported uranium.

'However, to say a duplicate of this land-based reactor is already inside Arihant and working is not correct,' he said. He pointed out that the official statement that Arihant's reactor will take at least a year to go critical is another way of saying there is no reactor core right now inside the hull since making a reactor critical only takes days, not months.