HEU repatriation - Canadian Nuclear Association

HEU repatriation

As part of the Canadian nuclear industry’s support for stronger global security, industry members are eliminating their use of highly enriched uranium (HEU). This uranium product, which could be used to build nuclear weapons, has been used in Canada for nuclear research and for the production of radioisotopes used in disease diagnosis and treatment, especially for cancer.

HEU is one of three “grades” of uranium:

  • Natural uranium contains approximately 0.7% uranium-235, which is the isotope that can be used in fission. The rest is uranium-238, which cannot undergo fission. Natural uranium can be used in CANDU reactors.
  • Low-enriched uranium (LEU) has been processed so that uranium-235 makes up a larger amount (usually 3% to 5%), and can be used in almost any nuclear reactor.
  • HEU has concentrations of uranium-235 between 20% and 90%. Certain Small Modular Reactor concepts use HEU enriched to about 20% as fuel, while nuclear weapons are made with HEU enriched to about 90%, so that they are extremely reactive.

Canadian Nuclear Laboratories (CNL), which runs the national nuclear laboratory at Chalk River, Ontario, is in the process of returning some 160 kg of HEU to the United States, as part of a 2010 agreement between the United States and Canada. The uranium is safely stored in two forms: solid fuel, which CNL used in its research reactors in the 1950s and 1960s; and uranium-bearing liquids used in the production of medical isotopes.

Shipments of solid uranium to the US Savannah River Site began following the agreement. Shipments of HEU liquids began following approval of a suitable cask for transportation by Canadian and US nuclear regulators in December 2014. Under the Canada-US agreement, shipments should be complete by 2018.

Radioactive materials have been transported safely nationally and internationally for more than 50 years by road, rail, water, and air, without a single incident of radiation exposure. The processes of transporting nuclear materials are detailed by both the CNSC and the World Nuclear Transport Institute.

The United States has been disposing of weapons-grade uranium and plutonium as part of its Global Threat Reduction Initiative. Since 1996, the initiative has removed several thousand kilograms of HEU and plutonium from over 30 countries.

Removing these nuclear materials to the United States improves Canada’s nuclear security and spares future generations of Canadians from the need to manage this security risk.