Chalk River, 2009 November 25 — 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 (CRL).

Welder training and weld equipment testing and verification in the NRU facility mock-up is now complete. Preparations are underway to disassemble the weld tooling for relocation to the top of the NRU reactor for installation. Once the equipment is in position, a test weld will be conducted. The test weld will be inspected and assessed prior to initiating the actual repairs. This is a pivotal step prior to commencing the weld repair at the actual repair sites.

Analysis and testing of the “scoop” samples taken from the wall of the reactor vessel in October is complete. Results from the analysis have been incorporated into the detailed weld plan. Analysis of the recent sample “coupon”, taken from one of the planned repair sites, continues. A team of experts in corrosion and metallurgy continue their examinations and testing of this sample in order to verify the corrosion mechanism and material properties prior to commencing weld repairs.

AECL continues to make progress on its schedule. Outage work has been demanding and technical challenges have arisen which have required that additional activities be added to the repair schedule. For example, based on the analyses of the scoop samples taken from the vessel wall, test weld and post weld non-destructive examination activities must now be added to the overall repair schedule. AECL continues to ensure that work is completed safely.

More information on the return to service of the NRU is available at NRUCanada.ca.

Evidence collected to-date continues to support AECL’s view that the necessary vessel repairs can be made and that the NRU will be safely returned to service.

Guidance on the duration of the shutdown 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. At this time, the application of the band weld build-up technique, and the number of identified repair sites indicates the NRU will return to service during the first calendar quarter of 2010. Further guidance on a return-to-service date will be provided when more information becomes available.

The Canadian Nuclear Safety Commission safety inspectors continue to provide independent regulatory oversight of AECL activities at the Chalk River site.

There is no threat to workers, the public, the environment or nuclear safety related to this event.

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Contact:

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