Given his background in nuclear physics, and in his roles as the chair of the cabinet committee and as scientific advisor to the DRDO, he was closely involved in the policy discussion about India's nuclear test. In October 1972, then Prime Minister Indira Gandhi gave the go-ahead for the Smiling Buddha test. Nagchaudhuri was a member of the steering committee for the test preparations. It was in the scientific laboratories of the DRDO, headed by Nagchaudhuri, that the explosive lenses for the test were fabricated. The test was successfully conducted in May 1974.