CNSC Approves Isotope Production at Darlington Nuclear Station

The Canadian Nuclear Safety Commission (CNSC) has amended Ontario Power Generation’s (OPG) operating licence for the Darlington Nuclear Generating Station to permit the production of the radioactive medical isotopes lutetium-177 (Lu-177) and yttrium-90 (Y-90) using equipment on Unit 2. The decision was announced on May 26, 2025, and follows a written public hearing process that included submissions from OPG, CNSC staff, and seven intervenors. The amended licence will remain valid until November 30, 2025.

According to the CNSC, Lu-177 and Y-90 are radioactive isotopes used in nuclear medicine, most prominently for targeted radionuclide therapy for certain types of cancer. The CNSC stated that the licence amendment enables OPG to produce these isotopes at the Darlington facility in Clarington, Ontario.

The CNSC indicated that it reached its decision after reviewing written submissions from OPG, CNSC staff, and intervenors and concluded that OPG is qualified to conduct the authorized activities. A regulatory hold point, as proposed by CNSC staff and accepted by the Commission, was established as part of the amendment. This hold point requires verification of safety measures, including commissioning tests, before isotope production can begin.

According to the CNSC, the record of decision and all related submissions will be posted on its website when available. Individuals may also request the record of decision from the CNSC Commission Registry.