Bruce A update

On Jan. 19, there was a spill of heavy water onto the floor of Unit 1 at Bruce A. Crews were completing maintenance on a moderator tank and a valve did not fully close as expected, resulting in the spill which was contained and fully collected within the powerhouse as designed. The spill was stopped immediately and the unit was taken offline.

There have been no adverse impacts to our employees, the environment or the public and the heavy water did not reach the natural environment.

An investigation to determine the cause of the event is underway and once complete, steps will be taken to implement any lessons learned.


Heavy water from the reactor contains levels of tritium and station staff follow procedures to prevent, mitigate and promptly address any spills to protect workers, the plant, public and environment. Procedures are in place to safely collect heavy water under these circumstances, which includes reducing access to the affected area, additional testing and confirmation of radiological protections, while clean-up is safely completed.