Defence: Nukewatch; Handle with Care

Defence

India Today
November 2,1998

NUKEWATCH: SAFETY MEASURES
Handle With Care

It makes military sense to disperse India's nuclear arsenal across the country. But the authorities must ensure that the weapons remain safe in storage and transit.

By Manoj Joshi

In early May when India transported five nuclear devices from Mumbai and Chandigarh airports to Jodhpur in preparation for the Shakti tests, the security was negligible. Though it was said that the plutonium cores and explosive triggers were transported separately and assembled only at the test site, this may not have been quite true in the case of the thermonuclear and boosted fission devices tested.

Had the aircraft crashed or a truck ferrying the materials from Jodhpur to Pokhran caught fire, besides the remote danger of a nuclear detonation, there would have been a plutonium hazard. The metal spewed across a vast area could have resulted in thousands of deaths as just one gram of it, if ingested, is enough to kill a human being. But given the circumstances, there was little choice but to transport the material the way it was, the great risk justified by the paramount need for secrecy.

India began fabricating nuclear weapons in 1990. Yet, western experts say nowhere in the country have they detected the kind of storage and security measures that normally accompany nuclear weapons in storage and transport. Indian officials claim that the need for deception requires their storage in unostentatious surroundings, but in view of the Shakti tests and India's self-proclaimed nuclear weapons' status, attention needs to be paid to the issue of safe storage and transport of weapons to the point of delivery at a target.

At the press conference detailing the tests, K. Santhanam, project director of the bomb programme, made it clear that some of the Indian tests involved weapons not devices. A prepared statement at the time referred to one of the three laboratories of the Defence Research and Development Organisation (DRDO) as being involved in "arming, fusing and safety interlocks", indicating that contemporary safety precautions associated with nuclear weapons had been incorporated into Indian designs.

India's first batch of nuclear weapons, based on the proven Pokhran-I design, was made in 1990. The simple design made for safety. The fissile cores were kept separate from the conventional explosive triggers. However, Pokhran-II has brought India into the age of more sophisticated weapons, of boosted fission and fusion. These not only require complex assemblies that cannot be kept disassembled but also safety features built into their designs.

A nuclear bomb explodes when electrical switches on each segment of the conventional explosive "lens" are charged. The explosive implodes simultaneously and symmetrically onto the fissile core and sets off the nuclear chain reaction. Working backwards are a number of steps that ensure this process occurs only after a number of other switches have been activated, some at the time of placing the weapon in the aircraft bomb stations, others when the aircraft is airborne. There are yet others that activate in sequence as the bomb is dropped, first as it falls off the aircraft, the next -- using a barometric pressure device at a pre-set altitude -- and finally as it descends a radar in the bomb's nose closes the final switch.

But that is not all. There is another set, the environmental sensing devices. When weapons are dropped, they experience near-zero gravity conditions. Subsequently there is rapid deceleration when a parachute is used to arrest the fall of the weapon. It is relatively simple to incorporate a switch that blocks critical electrical circuits till the bomb meets the required environmental conditions. Another important safety feature is the so-called one-point safety system. Should all interlocks fail, it is ensured that one of the conventional explosive lens will detonate, dismantling the device and preventing the explosion. Modern weapons also use conventional explosives that will simply burn in an accidental fire rather than detonate.

Given their power, worries about the accidental use of nuclear weapons never go away. In one instance in 1961, two 24 megaton bombs, each capable of wiping out Delhi and Mumbai combined, fell off a B-52 bomber near Goldsboro, South Carolina, USA. They were unarmed at the time of the accident, that is the initial programme of arming them, initiated by the pilots, had not yet taken place. However, when one of the bombs was recovered, five of six locks had been deployed because the weapon, which had descended by parachute, had met all the other conditions of descent.

While design features ensure against accidental detonation, the country's political leadership has to ensure that they can be delivered only by their rightful command. Since India has announced a "no first use" doctrine, Indian weapons are likely to be used in retaliation, that is, after an enemy attack. Given India's poor communications network, the most likely technique used will be through written orders sealed beforehand and can only be accessed in certain circumstances say, the destruction of Delhi, by designated military and civilian officers who will order designated air force squadrons to do the needful. Newer weapons may be provided with an electronic key, the so-called Permissive Action Links or pals.

Simply put, they are electronic combination locks that are integral to the weapons. These locks have a limited-try feature. Should any unauthorised person tamper with the weapons, one or more components will be destroyed or will malfunction, making the weapon useless. The process of arming the weapon cannot begin till it is unlocked by the use of one or several coded keys. The keys can be given to one or more field commanders or senior officials who will in turn activate them only if they get certain coded instructions through means whose authenticity would be beyond any doubt.

India's arsenal is likely to grow to some 150 warheads dispersed across the country. These weapons will have to be stored over years and on occasion be transported for maintenance to one or two facilities in the country. There will be a need, at times, to move them from one location to another to secure them against surprise attacks. This requires elaborate safety drills to ensure against accidents that can endanger Indian towns and cities and, equally important, against terrorist attacks.

Any national political leadership would want nuclear weapons that are always available for use but at the same time protected against accidental and unauthorised use. The safety and security of nuclear weapons therefore are issues that concern not just the DRDO and the Department of Atomic Energy alone. Prime Minister A.B. Vajpayee and his officials have gone out of their way to assure the world that India has a limited arsenal which it will never activate first against anyone. Perhaps it is also time to reassure the world about how safe the procedures for the storage and transportation of the weapons are and of the insurance they will never be used without legitimate orders.

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