Chalk River Information Bulletin

(2009 May 18) Atomic Energy of Canada Limited (AECL) reported on Friday, May 15th that the NRU reactor was safely shut down on Thursday, May 14th due to a loss of electrical power that occurred in parts of eastern Ontario and western Quebec.

During routine monitoring in the early morning hours of May 15th, a small leak of heavy water was detected within the NRU reactor facility. The leak rate is estimated to be at about 5 kg/hr. The heavy water is fully contained and is being stored in specially designed drums.

The location of the heavy water leak has been identified at the base of the reactor vessel in a location where there is corrosion on the outside wall of the vessel.  Repair options are currently under consideration and activities are being planned. As a result, AECL anticipates that the NRU reactor will remain out of service for more than one month.

Due to high airflow in the area, a small portion of the leakage evaporates and results in a monitored tritium release through the NRU ventilation system. Although the airborne release is well below regulatory limits, the release has reached action levels for tritium.  While this level does not pose a threat to the public or our workers, this is the level at which AECL reports to stakeholders and the Canadian Nuclear Safety Commission (CNSC).

AECL expects to meet its production requirements for medical isotopes for the coming week. However, based on the current delivery schedule, production will be unable to meet demand beginning Saturday (May 23rd) of this week.  AECL has notified Health Canada, and MDS Nordion of the current situation.

AECL confirms that there is no threat to workers, the public, the environment or nuclear safety related to this event.  The CNSC was first notified on Friday, May 15th and AECL will continue to provide updates to the CNSC and stakeholders when new information becomes available.

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For more information contact:

Dale Coffin
Director, Corporate Communications
AECL, 1-866-886-2325