External Affairs Minister Dr S Jaishankar has expressed grief over the demise of an Indian nuclear scientist Krishnamurthy Santhanam. In a tweet, Dr Jaishankar said, K.Santhanam was  deeply associated with Defence Research and Development Organization, Department of Atomic Energy and Institute for Defence Studies and Analyses. He said, Krishnamurthy Santhanam was a key figure in the Pokhran -2, 1998 tests. Dr Jaishankar said he educated a generation in the Ministry of External Affairs on technology regimes and export controls.<span style="color: #500050;"><br />'' <br />'' </span>Defence Minister Rajnath Singh has said that he is deeply anguished by the demise of Dr. K. Santhanam. In a tweet, Mr Singh said, he will be remembered for his remarkable efforts and contribution in the field of Science and Technology in India. He said, Dr. Santhanam was associated with institutions like DRDO, DAE and IDSA. Defence Minister said, his role in successful 1998 nuclear tests was noteworthy