In preparation of the upcoming weld build-up repair, cleaning of the NRU reactor vessel is progressing
- By April Murelio -
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).
Cleaning the NRU Reactor
In preparation of the upcoming weld build-up repair, cleaning of the NRU reactor vessel is progressing. Cleaning completed to date has successfully removed the 'gibbsite layer' (a normal wall surface build-up that occurs during reactor operation) that was located in the area to be repaired. Additional cleaning activities for final weld surface preparation are in development.
A more detailed explanation of the cleaning activities and the tool used to conduct the work is available in a video update released today on www.NRUCanada.ca. In the video, viewers are taken to the shop floor to see how AECL and Promation Nuclear worked together to design and manufacture the cleaning tools.
Repairing the NRU Reactor
Qualification of the welding process for the newly manufactured repair tools by the Technical Standards and Safety Authority (TSSA) is nearing completion. Two welding tests completed this week have met TSSA requirements. Further welding tool qualification and additional welding tests will be done before work to repair NRU begins. AECL employees continue to be trained on the use of the weld tooling at the vendor's facility.
Evidence collected to date continues to support AECL's view that the necessary vessel repairs can be made and that 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 (CNSC) 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.