 He retired as the Chairman Atomic Energy Commission of India (AECI) and the Secretary of Department of Atomic Energy (DAE) on April 30, 2012.Prior to his stint as DAE Chairman, he was the Director of Bhabha Atomic Research Centre (BARC) from April 30, 2004 to May 19, 2010.He is currently a DAE Homi Bhabha Chair Professor at Bhabha Atomic Research Centre, Mumbai.