Just ten days before the blasts, Chidambaram was playing father of the bride at his daughter's wedding. Even as dudhwalas and paper vendors shuffled about outside the wedding hall at 7:00 a.m. in Malabar Hill last month, the chairman of the Atomic Energy Commission (AEC) supervised last-minute arrangements for daughter Nitya's wedding even as he cleared two technical research papers. ``That's Chidambaram for you, a man without timings,'' says one of his Atomic Energy Commission colleagues, about the commission's workaholic chairman.

The responsibility for captaining India's nuclear test series has given this family man little time with his wife, Chella Mani, and two daughters. The green signal he received last month to thaw theIndian nuclear weapons programme has kept him on his toes. ``We always asked dad at the dinner table whether we really had the bomb,'' laughs his daughter Dr Nirmala Sridhar, who was as surprised by the nuclear tests as the rest of the country. Her father always responded to the question in the same, deadpan manner:``Oh! It's a big secret,'' he would smile in reply. The family had some inkling that a test was in the offing, when her father said he was going for a meeting in Delhi. Unusually for him, he didn't indicate when he would return.

Shorn of the aristocracy associated with past AEC heavies like Homi Sethna, Chidambaram is more the middle-class officer easily lost in a crowd. This is why he could slip into Mumbai on Thursday night and fly out to Chennai the next morning to attend his daughter's reception without being noticed.

``To say he is extremely brilliant is an understatement,'' says a scientist at the Bhabha Atomic Research Centre (BARC). It was in 1962 that Chidambaram stepped into thecrucible of the nation's nuclear programme. A top ranker at the Madras University in 1956, he bagged the Martin Forster Medal for having written the best thesis for his doctorate at the Indian Institute of Science, Bangalore.

``He was a promising young man, intelligent and eager to learn,'' recalls former AEC Chairman Dr P.K. Iyengar of the fresh PhD graduate and Solid State physicist, who although being born in Madras speaks Hindi fluently thanks to his Meerut schooling. He began as a crystallographer at the BARC -- cystallography being the study of the various physical properties of metals. In fact, to him should go the credit for having initiated neutron crystallogrpahy research in India. Today he is a member of the International Union of Crystallography, the American Crystallographic Association and the commission on neutron diffraction.

There were other areas too that he has contributed to, as for instance seismography. He headed the BARC's seismology section for a spell. But that was just one rungin the ladder. During the 1974 Pokharan blast, Chidambaram was director of the Physics group and responsible for making vital calculations after the explosion. A year later, he received the Padma Shri for guiding at least 20 students for their PhD.

He served in various capacities at the Centre -- a phase that culminated with his becoming director of the Bhabha Atomic Research Centre (BARC). Chidambaram turned out to be an innovator par excellence. In the 1970s, the dawn of the age of the big byte, he was responsible for the computerisation of the centre. Soon BARC had nearly 600 terminals, one for each of its scientists. In the '80s he ushered in the parallel processing computer, `Anupam', when the US embargoed the Cray supercomputer.

Today, juggling twin responsibilities of AEC chairman and secretary, Department of Atomic Energy (DAE), Chidambaram is the country's foremost nuclear mandarin controlling over 35,000 people in research and industrial units scattered all over the country.

When he's notshaping the country's nuclear destiny, he also takes time out to predict the future of Indian cricket. Colleagues were left stumped with the chairman's keen observations on the Indian cricket team. ``He makes shrewd guesses ranging from when Tendulkar's captaincy would end to predicting bowling attacks,'' says a colleague in the AEC.

He is also a tennis buff and can often be spotted wielding a racket at the AEC's court in Mumbai's Malabar Hill on Saturdays. A keen lover of Carnatic music and a patron of arts, Chidambaram is on the reception committee for the inauguration of the remodelled Shanmukhananda Hall, Mumbai's largest auditorium, which got burned down in a fire a few years ago.

Elusive and media shy as he is -- watch him give persistent mediapersons the slip at conferences -- Chidambaram is extremely accessible to colleagues in the establishment. Colleagues lavish praise on him for this trait and for the fact that `RC', as he is generally known, calls everyone by their first name. ``His demeanourputs you at ease, you can speak out openly before him,'' says a scientist. Another retired BARC official puts it this way, ``From workshop participants to international scientists, he has no inhibitions about interacting with anyone.''

A member and consultant of the International Atomic Energy Agency (IAEA), Vienna, he had a one-year stint as Chairman of its board of governors in 1994, a year after he was appointed the AEC chairman. His tenure at the helm of the AEC ends in November -- at around the time when US President Bill Clinton is scheduled to visit the country. But there's no cause for worry. Originally slated to retire in 1996, Chidambaram has already played out two extensions. There is no reason why he shouldn't be given another, says the nuclear fraternity.