Even prior to independence, Indian leaders were ambitious for nuclear capability both for the purpose of energy and defense. The Indian nuclear program can be roughly divided into three stages. The first stage includes Nehru’s emphasis on a large scale nuclear program for which a national commission was established.
In the mid sixties the nuclear program was only meant for energy but in 1974, India carried out a peaceful nuclear explosion test which can be considered as the second stage of the program. Simultaneously India increased its capability to build a nuclear arsenal as well as a missile program to deliver them.
On May 11, 1998, India carried out tests of three devices at the Pokhran followed by two more tests on May 13, 1998. The program was termed as “Operation Shakti”. By these tests India became one of the few nuclear power nations in the world. Apart from this, India is continuously engaged in the extraction of energy from nuclear power reactors located at various places in the country. This fulfills the huge energy demand of the country.
Over the last few decades, apart from nuclear reactors, India also developed facilities for mining Uranium, fabricating fuel, manufacturing heavy water, reprocessing spent fuel to extract Plutonium and more recently, enriching Uranium. Investment in this wide range of activities was often uneconomical. But it was justified on the grounds of self-sufficiency, a theme popular in post-colonial India. As the matter of nuclear weapon is concerned India has no 'first use' policy.
Find here the links for important Indian Nuclear Technology research institutes, centers and organizations: