It is curious how the nuclear test issue seems set to make or break the nuclear deal or the UPA government. Anyone who has been following US nuclear policy over the last four decades would have known that the professed US position on testing could not have been significantly different to what has been drafted into the agreement. The commotion at this juncture is indeed surprising.

Now that the debate is on, it is important to revisit the subject of nuclear testing.

The 1974 test, the so-called peaceful nuclear explosion (PNE) was of a rudimentary fission bomb. The claimed yield was about 10 to 12 kilotons. US estimates suggest the yield was around 4-6 Kt. The broadly accepted view is that the yield was below the expected 12-15 Kt. Debate on the subject had been brushed aside by the DAE scientists. But they did acknowledge that the size to yield ratio needed to be bettered and the device was not fit for use as a warhead.

Since 1982 the DAE and the DRDO had been working together in designing a nuclear device that required improvements in the symmetry (simultaneity) and its ruggedisation so that it could withstand the stresses of aircraft delivery or missile launch.

Twenty-four years later we tested again, this time in two stages. Three devices were detonated on May 11 1998 followed by another two, two days later.

The tests were meant to give our scientists ‘valuable data base — useful in the design of nuclear weapons — of different yields, different applications and different delivery systems’. They were directed to cover the full spectrum of nuclear weapons. The May 11 tests included fission and fusion (hydrogen/ thermonuclear) bombs and a sub kiloton (miniature) nuclear explosive device. The May 13 tests experimented with two more sub kiloton devices aimed at generating data for ‘improved computer simulation’.

... contd.