Commission amends Ontario Power Generation’s operating licence for the Darlington Nuclear Generating Station to authorize the production of lutetium-177 and yttrium-90

May 26 2025 – Ottawa

Today, the Canadian Nuclear Safety Commission (CNSC) announced the Commission’s decision to amend Ontario Power Generation’s (OPG) power reactor operating licence for the Darlington Nuclear Generating Station (NGS) to authorize the production of lutetium-177 (Lu-177) and yttrium-90 (Y-90) using the existing target delivery system on Darlington NGS Unit 2. This decision follows a public hearing in writing with interventions. The amended licence remains valid until November 30, 2025.

The Darlington NGS is located in the Municipality of Clarington, Ontario, within the traditional lands and waters of the Michi Saagiig Anishinaabeg, the Gunshot Treaty (1787–88), the Williams Treaties (1923), and the Williams Treaties Settlement Agreement (2018). 

In making its decision, the Commission considered written submissions from OPG, CNSC staff and 7 intervenors. After reviewing all submissions, the Commission concluded that OPG is qualified to carry on the activities that the amended licence will authorize.

The record of decision is available upon request by contacting the Commission Registry at interventions@cnsc-ccsn.gc.ca. It will also be posted in both official languages on the CNSC website at cnsc-ccsn.gc.ca at a later date. All submissions are also available on the CNSC website.

The CNSC regulates the use of nuclear energy and materials to protect health, safety, security and the environment; to implement Canada’s international commitments on the peaceful use of nuclear energy; and to disseminate objective scientific, technical and regulatory information to the public. The Commission is a quasi-judicial administrative tribunal set up at arm’s length from government, independent from any political, government or private sector influence.

Quick facts

• Lu-177 and Y-90 are radioactive isotopes that are used in nuclear medicine, most prominently for targeted radionuclide therapy of certain types of cancer. 
• The Commission is satisfied with the regulatory hold point proposed by CNSC staff to verify aspects of the safety case, including confirmation via commissioning tests, prior to declaring the new isotope production available for service.

Related links

• CNSC oversight of nuclear power plants
• CNSC oversight of the Darlington Nuclear Generating Station

Contact

Media Relations 
Canadian Nuclear Safety Commission 
Tel: 613-996-6860

Email: media@cnsc-ccsn.gc.ca