Throughout the 1960s–2000s AECL marketed and built CANDU facilities in India, South Korea, Argentina, Romania, and the People's Republic of China.

In addition, AECL manufactures nuclear medicine radioisotopes for supply to Nordion[1] in Ottawa, Ontario, and is the world's largest supplier of molybdenum-99 for diagnostic tests, and cobalt-60 for cancer therapy.

[2][3][4][5] Poor sales and cost overruns (CA$1.2 billion in the last five years) were reasons for the divestment though SNC-Lavalin expects to reverse that trend by focusing on new generation reactors.

Hundreds of military personnel from Canada and the U.S. (including naval officer and later U.S. President, LT James "Jimmy" Carter) were employed in the cleanup and disposal of the reactor debris.

The NRU is a world-renowned research facility, producing about 60% of the world's supply of molybdenum-99, the principle isotope used for nuclear medical diagnosis.

A damaged uranium fuel rod caught fire and was torn in two as it was being removed from the core, due to inadequate cooling.

The fire was extinguished, but not before releasing a sizeable quantity of radioactive combustion products that contaminated the interior of the reactor building and, to a lesser degree, an area of the surrounding laboratory site.

Later work on developing a SLOWPOKE reactor, thorium fuel cycle, and a proposal for safe storage of radioactive waste were carried out at this site.

AECL built a larger CANDU prototype (200 MWe) at Douglas Point on Lake Huron, first going critical on November 15, 1966.

Douglas Point experienced significant problems with leakage of heavy water, which were eventually solved by much-improved valve design.

Other important design refinements worked out at Douglas Point opened the way for upscaling to commercial power CANDU reactors in subsequent years.

Between 1985 and 1987, a series of design flaws in AECL's Therac-25 medical accelerator caused massive overdoses of radiation[18] on 6 different occasions, resulting in five deaths.

In 1987 the machine was found defective by the Food and Drug Administration (FDA) and eventually recalled by AECL despite their multiple denials that the problems existed.

[20] With a contract signed in 1991, AECL, in partnership with MDS Nordion, began construction of the MAPLE dedicated isotope-production facility.

The first reactor was started but experienced malfunctions in its safety rods, and a positive nuclear power feedback coefficient was recorded.

[citation needed] After running over the Schedule by more than 8 years and more than doubling the initial budget, AECL cancelled the project in 2008 because the design was flawed.

[21] Energy Alberta Corporation announced August 27, 2007, that they had filed application for a license to build a new nuclear plant at Lac Cardinal (30 km west of the town of Peace River.

The application would see an initial twin AECL Advanced CANDU Reactor (ACR) plant go online in 2017, producing 2.2 gigawatt (electric).

The Ontario government has since suspended the acquisition process citing the cost and uncertainty surrounding the companies future ownership (discussed below).

[25] Medical isotope production using the 1957-built NRU reactor experienced two forced outages due to safety concerns (December 2007)[26][27] and a heavy water leak (May 14, 2009).

[28] The production from the NRU reactor represented a significant fraction of the worlds medical isotope supply and the disruptions caused a worldwide shortage.

Concerns raised about the deal include a lack of commitment by SNC-Lavalin to keeping the design division intact (its size makes it more capable of providing ongoing safety support).