NRU Status Report No. 32

AECL provides update on NRU activities

CHALK RIVER, ON, Dec. 2 /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).

The specialized tooling and equipment for the weld repair has now been installed at the NRU reactor. A series of test welds inside the vessel have been initiated. Based on the experience obtained through the test welds, adjustments are being made to improve visibility through the remote camera that is operating in high radiation fields. Once satisfactory weld results are achieved, the test weld will be inspected and assessed prior to initiating the actual repairs.

AECL is collaborating closely with third-party welding experts including The Welding Institute (TWI) of the UK, global specialists in materials-joining technology. These experts are assisting with the development and testing of welding techniques in this unique and challenging environment.

A preliminary report on the corrosion mechanism indicates that the nitric acid formation in the J-rod annulus is likely the only cause of the corrosion. Further examination and analysis will be carried out prior to preparing a final report.

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