<P> The timing of the tests depended on the local weather conditions, with the wind being the critical factor . The tests were underground, but due to a number of shaft seal failures that had occurred during tests conducted by the United States, the Soviet Union, and the United Kingdom, the sealing of the shaft could not be guaranteed to be leak - proof . By early afternoon, the winds had died down and the test sequence was initiated . Dr. K. Santhanam of the DRDO, in charge of the test site preparations, gave the two keys that activated the test countdown to Dr. M. Vasudev, the range safety officer, who was responsible for verifying that all test indicators were normal . After checking the indicators, Vasudev handed one key each to a representative of BARC and the DRDO, who unlocked the countdown system together . At 3: 45 pm the three devices were detonated . </P> <P> Five nuclear devices were Made during Operation Shakti . All devices were weapon - grade plutonium and they were: </P> <Ul> <Li> Shakti I--A thermonuclear device yielding 45 kt, but designed for up to 200 kt . </Li> <Li> Shakti II--A plutonium implosion design yielding 15 kt and intended as a warhead that could be delivered by bomber or missile . It was an improvement of the device detonated in the 1974 Smiling Buddha (Pokhran - I) test of 1974, developed using simulations on the PARAM supercomputer . </Li> <Li> Shakti III--An experimental linear implosion design that used "non-weapon grade" plutonium, but which likely omitted the material required for fusion, yielding 0.3 kt . </Li> <Li> Shakti IV - A 0.5 kt experimental device . </Li> <Li> Shakti V--A 0.2 kt experimental device . </Li> </Ul> <Li> Shakti I--A thermonuclear device yielding 45 kt, but designed for up to 200 kt . </Li>

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