On May 18, 1974, India detonates a 12-kiloton nuclear explosive in the Rajasthan desert, using plutonium from a research reactor donated by Canada in 1956. The explosion prompts fierce criticism of Canada's nuclear exports, and a wall of excuses from officials in both Canada and India. Canadian officials say they couldn't stop it. India denies it was even a bomb.

• The nuclear device was built using plutonium obtained from the 40-megawatt Cirus research reactor, a gift from Canada. It was donated under the Commonweath "Colombo Plan" aid program, which sought to promote economic and social development in South and Southeast Asia.
• The gift helped pave the way for future reactor sales: Canada sold India two Candu reactors (in 1963 and 1966), and they now have a number of Candu clones.

• The Cirus reactor was modeled on the Chalk River NRX reactor. It was donated on the condition that it only be used for peaceful purposes – so India claimed their 1974 explosion was "peaceful" and would help them in industries such as mining.

• India referred to the device as the "Peaceful Nuclear Explosive" or PNE. It was also called "Smiling Buddha."

• The 1974 explosion was criticized around the world, and most nations (including Canada) stopped lending India technical assistance. India soon built a plutonium separation plant to help refine plutonium from its nuclear waste, and developed its own nuclear reactors based on the Cirus design. That gave India a legal source of plutonium with which to make bombs.

• Canada sold a 125-megawatt reactor to Pakistan in 1959 and a Candu in 1964. After India's nuclear test in 1974, Canada wanted Pakistan to promise never to build a bomb using plutonium from Canadian reactors, but Pakistan, which went to war with India in 1965, refused. Pakistani Prime Minister Zulfiqar Ali Bhutto declared that Pakistan would build the bomb "even if we have to eat grass or leaves or to remain hungry."

• The Treaty on the Non-Proliferation of Nuclear Weapons (NPT) was introduced in 1968 and became international law in 1970. It was signed by 187 nations promising to stop the spread of nuclear weapons to nations that did not have them, and to promote disarmament among those that did. At the time Cuba, India, Israel and Pakistan refused to sign the treaty. In 2002, Cuba signed the treaty, but in 2003 the Democratic People's Republic of Korea (North Korea) withdrew.

• On May 11 and 13, 1998, India detonated underground nuclear bombs, admitting to the world that it now had the bomb. By the end of the month, Pakistan responded with test blasts of their own.

Medium: Radio
Program: As It Happens
Broadcast Date: May 20, 1974
Host: Harry Brown, Interviewer: Barbara Frum
Guest(s): Donald G. Hurst, Samar Sen
Duration: 7:49