April 8, 2013 — Atomic Energy of Canada Limited (AECL) will commence a 30-day planned shutdown for inspection and maintenance of the National Research Universal (NRU) reactor at Chalk River, Ontario, starting April 14, 2013. This planned shutdown, which AECL has advised will last until May 14, 2013, will result in an interruption in the supply of medical isotopes used in nuclear imaging procedures in the United States. Chalk River is one of the primary sources for the isotopes used in nuclear imaging radiopharmaceuticals.
This planned outage is a requirement of AECL’s operating license issued by the Canadian Nuclear Safety Commission (CNSC). This marks the third annual outage for the NRU. Inspection results to date continue to confirm that the NRU aging reactor remains fit for service.
In addition to the annual vessel inspection, work is planned during the outage to enhance the reliability and safety of NRU. A dedicated work management outage team has been established to coordinate the activities of suppliers, NRU specialists and supporting departments ensuring the safe and successful execution of the outage.
Facility users and the isotope community have been informed well in advance of this outage and have taken steps to adjust their activities.
For more information: www.aecl.ca/About/Offices/Labs.htm
November 12, 2025 
