NRU Status Report No. 33 - AECL provides update on NRU activities

CHALK RIVER, ON, Dec. 9 /CNW/ - 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).

AECL has successfully completed a test weld on the surface of the NRU vessel wall that simulates the repair welds. The test was conducted remotely by operating the welding equipment from a position of approximately 30 feet above the location of the test site. Welding specialists, working with vendor-supplied equipment, controlled the weld build-up process using remote visual feedback displayed on monitors located on the reactor deck.

Based on the test weld, a series of non-destructive examinations is underway and a "scoop" sample of the test weld has been taken. This sample will provide necessary information to determine the quality of the weld build-up. Metallurgical and material specialists are reviewing the data before initiating the actual vessel repair.

With the completion of the first test weld, AECL has now achieved 13 of the 19 milestones in its NRU Return-to-Service Plan.

In addition to the progress on welding, AECL was also able to confirm that nitric acid formation in the J-Rod Annulus is the primary cause of corrosion. This understanding has provided the necessary information to help AECL take specific measures to reduce the reoccurrence of this kind of corrosion during the future operation of NRU.

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.

For further information: Dale Coffin, Director, Corporate Communications, AECL, 1-866-886-2325