India's top missile scientist, Avinash Chander, said the nuclear-tipped missiles were ready for installation and their integration would begin after some of the scheduled sea trials are over. The submarine is in its home port of Visakhapatnam now, but should set course for the sea within a few weeks - by March - once its reactor achieves full power in the step-by-step process.
"All weapons are ready. INS Arihant is going through the steps of induction, and we are slowly raising the power to 100 per cent. After that, it will be ready to go to the sea. The process is a fairly elaborate exercise which will take several months. Once Arihant is in the sea, there has to be a trial phase of six to eight months," Chander told India Strategic magazine ahead of the DefExpo in New Delhi.
Chander, who is the Scientific Adviser to the Defence Minister and also the Director General of the Defence Research and Development Organisation (DRDO), which is leading India's quest for nuclear weapons requirements, observed that extreme care is needed in fully activating a new submarine's reactor to establish total safety parameters.
"It is the first baby we are nurturing," he said with optimistic caution.
Nuclear energy is amazing on the one hand as it can generate an endless supply of power and dangerous on the other, if its production is not scientifically controlled and handled. The equipment on board a submarine and the men assigned to manage and handle it have to work in total sync and sensitivity. The margin for error is zero.
"So, it will be a careful, step-by-step operation and as soon as we are comfortable with the step-by-step established parameters, the submarine would set course for the sea for designated and pre-determined further trials," the distinguished scientist observed.
He said he did not want to put a time-frame, but would expect it to "happen in a couple of months - say March".
Chander did not disclose details about INS Arihant's weapons, but it is understood that its four tubes are designed to launch 750-km range K-15 missiles and 3,500-km range K-4 missiles. Both these are nuclear tipped, capable of destroying any large city.
INS Arihant will carry 12 K-15 and four K-4 missiles. There is provision to launch non-nuclear tipped Brahmos supersonic cruise missile as well as the 1,000-km Nirbhay which can be configured for both nuclear and non-nuclear warheads, and has some loitering capability.
All these missiles have been tested successfully from underwater pontoons.
India is reportedly looking at three or four nuclear-propelled Arihant-class submarines and a larger number - 10 or 12 - of nuclear propelled attack submarines of a larger class. The latter, designated internationally as SSN boats, move fast along with Carrier Battle Groups (CBGs) while the nuclear armed boats like the Arihant, designated as SSBN, stay in hiding for three or four months as part of deterrence strategy. SSN boats carry submarine launched cruise missiles (SLCMs) like the Brahmos, or Nirbhay.
Technically, a nuclear boat can stay under water for very, very long periods but the limit to human endurance is generally put at about three months.
It may be noted that conventional diesel-electric boats can stay underwater for three days to a couple of weeks only, as they have to surface periodically to draw air to recharge their batteries.
The Indian Navy has some 45 vessels on order but at present, its submarine arm is very weak as the boats are old - acquired from mid-1980s - except for the nuclear-powered INS Chakra leased from Russia. INS Arihant has an 80 MW pressurised water reactor, based on Russian subs. Some of the crew trained by Russia for INS Chakra have reportedly been helping in the test procedures.
Notably, the navy is looking for three aircraft carriers in the coming years, and it is imperative to have nuclear-powered boats as part of the overall strategy. The carriers, which are like floating islands, themselves need 360 degree protection up, down, around and underwater and SSN boats are a basic requirement if a country goes in for CBGs.
Nuclear weapons can be launched from air, sea or land, and SSBN boats are hidden in ocean depths so that they can survive a nuclear attack by a hostile country, and then be able to take retaliatory action.
India has a declared No-First-Use (NFU) nuclear doctrine, which however promises massive punitive destruction in retaliation. Submarine-launched nuclear weapons are part of this strategy. Once INS Arihant is operational in 2015, India will then complete the nuclear triad of air, surface and underwater nuclear attack capability.
Nuclear weapons are under the tri-service Strategic Forces Command (SFC) and top level clearance is required from the government to launch them if ever needed.