Chalk River Information Bulletin

(2009 July 22) The following information bulletin is in accordance with Atomic Energy of Canada Limited's (AECL) ongoing commitment to voluntary public disclosure of events related to the Chalk River Laboratories.

Analysis of the data collected from Non Destructive Examinations (NDE) of the interior of the vessel continues. Approximately 500,000 data points were gathered during the initial phase of NDE inspection of 80 per cent of the vessel.

The NDE team is currently completing fabrication of the new Mark II NDE inspection probe. The new probe will be used to inspect areas of the vessel that are otherwise inaccessible. Following training on the use of the probe, the team will resume the vessel inspection process.

AECL continues to work with its specialized vendors on proving repair concepts, and cleaning techniques. Cleaning of the annulus surrounding the vessel has commenced.

The vessel has now been completely drained of heavy water and the leak has stopped.

In the reporting period (July 08 to July 15) prior to draining the vessel, monitoring data confirmed that the action level for tritium release to the atmosphere was exceeded. AECL reported these monitoring results to the CNSC on Friday, July 17.

Evidence collected to date continues to support AECL’s belief that the necessary vessel repairs can be made and that NRU will be returned to service. The minimum duration of the outage continues to be founded on the best evidence available, including the most up-to-date analysis of the inspection data, progress on repair strategies, and critical path requirements for restart after an extended shutdown.

Further guidance on a return to service date will be provided as more data is collected and analyzed, and the decision is made about the repair technique and extent of required repairs.

AECL continues to work very closely with the Canadian Nuclear Safety Commission (CNSC), and CNSC safety inspectors are directly involved at the Chalk River site.

There is no threat to workers, the public, the environment or nuclear safety related to this event. More information on the repair and status updates on the NRU is available at http://www.nrucanada.ca

For more information contact:

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