The question of publication of information on atomic energy is reviewed in the light of changing conditions, including the evidence of an atomic explosion in Russia. At meetings of representatives of the U.S., UK and Canada, recommendations are made to more widely declassify fundamental scientific information while maintaining restrictions on publication of technological data that might be of assistance to a potential enemy. The three governments subsequently consider these recommendations. (Source: AECB)

A plutonium recovery laboratory begins operating at Chalk River Laboratories to extract plutonium isotopes from enriched fuels used in research reactors. (Source: AECB)

Eldorado begins to sell cobalt-60. (Source: Eldorado , Robert Bothwell, p. 226)

Dr. Harold Johns operates the first betatron in Canada at the University of Saskatchewan. A patient is treated for cancer with a 24-MeV betatron at the University, marking the first-ever concerted clinical use of this equipment. The machine, which delivers high-dose radiation with minimal damage to overlying skin, treats 301 patients over the next 17 years. (Source: University of Saskatchewan)

The Gilbert U-238 Atomic Energy Lab was the most elaborate atomic energy educational set ever produced, but it was only available from 1951 to 1952. Its relatively high price for the time ($50.00) and its sophistication were the explanation Gilbert gave for the set's short lifespan. Today, it is so highly prized by collectors that a complete set can go for more than 100 times the original price.

Dr. John Robson publishes his verification of the radioactive nature of the neutron along with the first accurate measurement of its half-life (12.8 +/- 2.5 minutes). These findings are made using the National Research Experimental (NRX) reactor at the National Research Council's Atomic Energy Project at Chalk River, Ontario. (Source: Physics Review , No. 83, pp. 349–358 (1951)

Animated classic presenting what an atom is, how energy is released from certain kinds of atoms, the peacetime uses of atomic energy and the by-products of nuclear fission. Producer: John Sutherland Productions Sponsor: General Electric Company

In the Joule Memorial Lecture of 1951, Sir John Cockcroft, the first director of Chalk River's nuclear laboratories, says of UK reactor development: "We do not expect to produce a cheaper source of power than that derived from coal – it is likely, in fact, to be somewhat more expensive. What we are aiming at is to increase the total power available.” He concludes by saying, "The essential thing is now to get on and build some power reactors." (Source: Canadian Nuclear Society)

Eldorado expands its line of radioisotopes. (Source: Isotopes and Innovation , Paul Litt, p. 50)

The government authorizes construction of an additional reactor at Chalk River; engineering design of the reactor begins. The AECB reports, "While the details of design must remain secret, it may be said that the new reactor will use heavy water as a moderator. It will be more powerful and have a higher neutron flux density than the National Research Experimental [NRX] reactor pile, and will be adapted to extend greatly the range of possible research, as well as to increase production of plutonium and radioisotopes." (Source: AECB)

Canada’s first beam therapy units, which treat cancer using cobalt-60, are installed at the University of Saskatchewan and in London, Ontario. The units were built by Dr. Harold Johns at the University of Saskatchewan and Roy Errington of Eldorado Mining and Refining. (Source: Canadian Nuclear Association)

The world’s first cancer treatment using Eldorado’s cobalt-60 machine is applied. The treatment – called cobalt radiotherapy – is used on a patient at Victoria Hospital in London, Ontario. (Source: Canadian Nuclear Association )

Cobalt radiotherapy is applied to a patient using Harold Johns's machine in Saskatoon, Saskatchewan. (Source: Isotopes and Innovation , Paul Litt)

Atomic Energy of Canada Ltd. acquires Eldorado's Commercial Products Division. (Source: Nucleus: The History of Atomic Energy of Canada Limited , Robert Bothwell, p. 146)

Atomic Energy of Canada Ltd. begins operating a wastewater evaporator to process and treat liquid waste from fuel reprocessing at the National Research Experimental (NRX) reactor. The system remains active until 1968. Stored waste from earlier fuel processing is concentrated through evaporation from 1958 to 1967. (Source: Canada Enters the Nuclear Age , Atomic Energy of Canada Ltd.)

Dr. E.W.R. Steacie is appointed as an ex officio member of the AECB and serves until August 28, 1963. (Source: A History of the Atomic Energy Control Board, Gordon H.E. Sims)

Atomic Energy of Canada Ltd. (AECL) separates from the National Research Council and becomes a Crown Corporation because of its increasingly commercial activities associated with the research reactors at Chalk River headed by AECB President C.J. Mackenzie. (Source: Nucleus: The History of Atomic Energy of Canada Limited , Robert Bothwell, p. 144)

The core of the National Research Experimental reactor at Chalk River Laboratories undergoes a partial meltdown, as the result of an accident involving rupture of some tubes in the calandria, resulting in significant damage that puts it out of service for 14 months. Future U.S. President Jimmy Carter, then a U.S. Navy serviceman, is part of the clean-up crew.(Source: Canadian Nuclear Society)

Eldorado Mining and Refining Ltd. stops its radium refining activities in Port Hope, Ontario. It dismantles its refinery and removes facilities from the site. (Source: Port Hope Area Initiative)

Eldorado Mining and Refining Ltd. begins operating the Beaverlodge Mine in northern Saskatchewan, the first uranium mining operation in Canada after Port Radium, Northwest Territories. (Sources: Eldorado , Robert Bothwell, pp. 302-304; A History of the Atomic Energy Control Board, Gordon H.E. Sims, p. 222)

At the Chalk River Project, the AECB reports, “considerable progress has been achieved during the year in the acquisition of new basic knowledge of nuclear science in its many phases, as well as in the chemical separation operations and isotope production processes.” (Source: AECB)

Atomic Energy of Canada Ltd. begins a power reactor feasibility study to determine an outline specification for a small prototype power reactor and forms a study team with representatives from the Hydro Electric Power Commission of Ontario. (Source: Canadian Nuclear Society)

The AECB Annual Report 1953–1954 notes, "It is now generally recognized that electric power can be obtained from atomic energy. It also appears probable, even on the basis of present knowledge, that atomic energy may soon be made to compete economically with other sources of power, and great interest is therefore being shown in atomic energy power developments. The Right Honourable C.D. Howe, in February 1953, intimated that the participation of Canadian producers and distributors of electric power in the discussion of these developments would be welcome." (Source: AECB)

Atomic Energy of Canada Ltd.’s Theratron B is tried for the first time at Francis Delafield Hospital in New York City. (Source: Isotopes and Innovation , Paul Litt, pp. 85–86)

In its Annual Report , the AECB explains, “Growing out of the Eisenhower proposals of December, 1953, for an international agency to promote the peaceful uses of atomic energy, a resolution for the establishment of such an agency was unanimously adopted by the General Assembly of the United Nations, and discussions on the constitution of the agency have been proceeding. The General Assembly has also approved of the holding of an international conference on the peaceful uses of atomic energy, which is to be held in Geneva in August, 1955, and to which 84 nations have been invited to send representatives.” (Source: AECB)

Changes to the Atomic Energy Control Act separate Atomic Energy of Canada Ltd. and Eldorado from reporting responsibilites to the AECB, thus lessening the AECB's influence over the respective organizations. (Source: A History of the Atomic Energy Control Board , Gordon H.E. Sims)

Atomic Energy of Canada Ltd. concludes its small prototype nuclear power reactor design study and requests proposals from industry and utilities for construction and operation. The prototype station will be called Nuclear Power Demonstration.

Amendments to the Atomic Energy Control Act remove the operational responsibilities of Atomic Energy of Canada Ltd. (AECL) from the Atomic Energy Control Board (AECB). AECL, created two years prior in order to operate the Chalk River Laboratories nuclear research facilities, now reports directly to a federal Cabinet Minister instead of the AECB. (Source: AECB)

Dr. W.B. Lewis fosters collaboration between Atomic Energy of Canada Ltd., Ontario Hydro and Canadian General Electric that leads to the development of the CANDU reactors that are still in use around the world today. However, the term CANDU would not be used until the 1960s. (Source: Canadian Nuclear Association)

The National Research Experimental (NRX) reactor in Chalk River resumes operations following implementation of design improvements to both prevent another similar failure that caused the partial meltdown in 1952 and to boost power output from 30 to 40 megawatts.

An amendment is made to the Atomic Energy Control Act to provide for the integration of the AECB under a Minister of the Government’s research and raw materials activities. The staff of the AECB is also brought under the Public Service Superannuation Act . The amendment receives royal assent June 26, 1954. (Source: AECB)

Atomic Energy of Canada Ltd.'s Commercial Products Division moves to new headquarters at Tunney’s Pasture in Ottawa. (Source: Isotopes and Innovation , Paul Litt)

The first sailing of a nuclear-powered ship (the USS Nautilus ) takes place. Atomic Energy of Canada Ltd.'s Chalk River Nuclear Laboratories had been involved in testing the fuel (UO2) for the U.S. reactors, and the Commercial Products Division (CPD) provided the radium-beryllium neutron sources required to start the reactors. (Source: Submarine Force Museum)

The Agreement for Co-operation Concerning Civil Uses of Atomic Energy Between the Government of Canada and the Government of the United States of America is signed. The agreement enables the exchange of classified and unclassified atomic energy information. It comes into effect in July 1955. (Source: Lexum)

The first International Conference on the Peaceful Use of Atomic Energy is held by the United Nations in Geneva. A unanimous resolution is adopted to establish an international agency to promote the peaceful uses of atomic energy. (Source: International Atomic Energy Agency)

A commercial version of the National Research Experimental (NRX) reactor, the CIRUS, is sold to the Indian government with the intent of peaceful use. India eventually uses the reactor to obtain plutonium for a nuclear test known as Operation Smiling Buddha. (Source: Nucleus : The History of Atomic Energy of Canada Limited , Robert Bothwell, pp. 355, 429)

The AECB establishes the Reactor Safety Advisory Committee. Its purpose is to consider the health and safety aspects of proposed nuclear projects and to then make recommendations to the AECB. (Source: A History of the Atomic Energy Control Board, Gordon H.E. Sims, pp. 117, 120)

Ground is broken at the Nuclear Power Demonstration Plant in Des Joachims, Ontario, with the Right Honourable C.D. Howe and the Honourable Leslie M. Frost turning the first sod. (Source: Canadian Nuclear Society)

Atomic Energy of Canada Ltd.'s Commercial Products Division (CPD) introduces the Gammacell irradiator at the New York Atom Fair. (Source: Isotopes and Innovation, Paul Litt)

The Honourable Gordon Churchill, Minister responsible for nuclear matters, 1957–1962

The plutonium recovery laboratory at Chalk River Laboratories shuts down and most of the processing equipment is flushed, decontaminated and removed. Further cleanup and dismantling is carried out in the 1980s. (Source: CNSC)

The Gunnar and Pronto uranium mines open. (Source: Saskatchewan Research Council)

A 10kWt pool-type reactor is built at Chalk River Laboratories. The pool test reactor operates on 93% enriched uranium aluminum plate-type fuel and is used for burnup measurement of fissile samples from the National Research Experimental (NRX) reactor. (Source: Atomic Energy of Canada Ltd.)

The AECB makes it a condition for exploration and mining permits that provincial mine safety regulations be followed. (Records indicate that this was simply declaratory as provincial mine safety laws were already being followed in uranium mines.)

The UN Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) is established to study the amount of radiation people receive from various sources.

The AECB authorizes the construction of a small research reactor at McMaster University in Hamilton, Ontario. This is the first non-government reactor project in Canada. In 1956, to assist in reviewing this and other similar applications that were expected, the AECB had established a Reactor Safety Advisory Committee consisting of federal, provincial and university experts, chaired by Dr. G.C. Laurence.

The International Atomic Energy Agency is established to promote the peaceful use of nuclear energy and to establish and administer safeguards against the proliferation of nuclear weapons. (Source: AECB)

The National Research Universal (NRU) reactor begins operating at Chalk River Laboratories. Its high neutron flux and versatility make it one of the world’s finest reactors and a showcase for Canadian technology on the international stage. Eventually the NRU becomes the world's first reactor to refuel while operating at full power. (Source: Canadian Nuclear Society)

Atomic Energy of Canada Ltd.'s Commercial Products Division (CPD) develops Theratron Jr., the first of 140 such radiation therapy machines sold worldwide.

Canada becomes an associate member of the newly created Nuclear Energy Agency (NEA) of the Organisation for Economic Co-operation and Development (OECD).

A fuel rupture and fire occur in the National Research Universal reactor building at Chalk River Laboratories. A major cleanup effort involving many civilian and military personnel is required. Follow-up health monitoring of these workers reveals no adverse impacts. (Source: Canadian Nuclear Association)

Prime Minister John Diefenbaker describes the basic principles behind “Continuity of Government,” a framework for the protection and support of key government elements in case of a massive nuclear attack on North America.

Mr. J.L. Gray is appointed as a member of the AECB and serves until January 12, 1973.

Mr. W.M. Gilchrist is appointed as a member of the AECB and serves until November 1974.

Significant numbers of Canadians oppose federal government plans to purchase nuclear-warhead-capable Bomarc missiles from the United States. The controversy will last until September 1963, when Prime Minister Lester Pearson announces that Canada will purchase nuclear missiles from the United States. However, after Canada ratifies the Nuclear Non-Proliferation Treaty in 1969, nuclear warheads begin to be removed from the country. (Source: Diefenbaker Canada Centre)

By 1959, the AECB's main activities have been refined to such a degree that a statement is needed in the annual report explaining its chief function as making and administering regulations on nuclear matters in the interest of national security and of health and safety for users and the public.

Draft regulations establishing a minimum standard of health and safety for the use and handling of y-emitting materials are prepared by the Department of National Health and Welfare in consultation with Atomic Energy of Canada Ltd. and the Atomic Energy Control Board.

The AECB authorizes construction of the Douglas Point reactor.

Deliveries in 1959 of uranium oxide (U3O8) in concentrates from Canadian mines total 15,909 tons, valued at $333,577,990.

Construction begins on Canada’s primary Cold War secret defence facility, colloquially known as the Diefenbunker, on the outskirts of Carp, Ontario. Today the Diefenbunker operates as a museum offering public tours of the facility. (Source: Parks Canada)

The U.S. Government announces it will not renew its uranium contracts.

A policy directed at radioisotope users requires all users of y-emitting materials to use the film monitoring service provided by the Department of National Health and Welfare.

The McMaster Nuclear Reactor, located at McMaster University in Hamilton, Ontario, begins operating. The reactor is the first university-based research reactor in the British Commonwealth. (Source: McMaster University)

Canada sells a 125-megawatt nuclear reactor to Pakistan.

The Hydroelectric Power Commission (Ontario Hydro) acquires 2,300 acres of land at Douglas Point for $50–70 per acre.

The Canadian Nuclear Association is established as a non-profit organization to represent the nuclear industry in Canada and to promote the development and growth of nuclear technologies for peaceful purposes.

Amended Regulations authorize the AECB to stipulate health and safety precautions addressing prescribed (nuclear) substances. The Regulations also introduce the concept of atomic radiation workers and establish protective procedures and acceptable levels of exposure. Inspection officers (including officers of a province if authorized by the AECB) are introduced in the amendment and given a significant role in protecting health and safety. (Source: A History of the Atomic Energy Control Board , Gordon H.E. Sims)

Canada’s government agrees to have defensive nuclear weapons based in Canada under joint Canadian–American custody and control pursuant to the North American Air Defence Agreement (NORAD Agreement). This requires the Department of National Defence to consult with the AECB to assure there are appropriate emergency procedures and measures for health, safety and security.

Canada India Research US (CIRUS) begins operations. It was from this reactor and reprocessing facilities that India was able to secure plutonium and use it to detonate India’s first nuclear bomb in 1974. (Source: Nucleus: The History of Atomic Energy of Canada Limited , Robert Bothwell, pp. 355, 429)

Construction begins on Canada's first commercial-sized (200 MW) CANDU nuclear power plant, located in Douglas Point, Ontario. Contracts for the station’s components go to 600 Canadian firms (71% of all vendors) as well as companies in the UK (17%) and U.S. (12%). As a prototype, the plant is to be owned by Atomic Energy of Canada Ltd. and operated by Ontario Hydro. Construction has been underway since June 1958 on the Nuclear Power Demonstration – a small demonstrator CANDU (22 MW) – at Rolphton, Ontario.

“The AECB writes, “Section 9 of the Atomic Energy Control Act authorizes the Board, with the approval of the Governor in Council, to make regulations for encouraging and regulating the development of atomic energy … In view of the increasing use of radioactive isotopes for industrial, research and medical purposes, of progress made toward definition of acceptable standards of permissible exposure of radiation, and of the steady increase in the release of information on atomic energy, it was felt that the regulations should be revised to reflect these changes.”

The Atomic Energy Control Regulations are amended, allowing the AECB to control the health and safety of nuclear energy industry workers and to establish a schedule of maximum levels of ionizing radiation to which these workers can be exposed. (Source: A History of the Atomic Energy Control Board , Gordon H.E. Sims)