AECL Provides Update on NRU Activities Relating to Chalk River Laboratories
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 reports that the NRU reactor vessel repair activities are currently focused on preparation work in advance of the next series of weld repairs. To date, 29 per cent of the repair activities are complete.
In order to ensure that no undesirable structural effects occur to the vessel during repairs, AECL and third-party experts continue parallel stress calculations for each of the next series of weld repairs. The stress calculations consider the geometry of the repair sites, the weld procedure, and the number of layers of weld buildup to be applied. Based on the results of the analysis of the stress calculations, AECL engineers have approved the next weld repair.
Two horizontal weld machines are now qualified to proceed with weld repairs. A third horizontal weld machine is undergoing qualification. The AECL and Liburdi Automation Inc. welding teams have completed their reliability practice welds and are qualified to proceed with the next series of repairs.
Plans are being modified to optimize the schedule recognising that safety and a high quality repair must be maintained. The current schedule targets return to service by the end of March 2010. However, if there are continuing challenges with the repair process, the NRU return-to-service schedule could extend into April.
Further guidance on a return-to-service date will be provided when repairs to all sites have been undertaken. The repairs are scheduled to be completed in February.
The first medical isotopes will begin to be removed from the NRU for processing and distribution within 10 days of the reactor being returned to service.
In August 2009, The Canadian Nuclear Safety Commission (CNSC) and AECL established a "Protocol for the NRU Restart Licensing Activities". The Protocol, signed jointly by CNSC President & CEO Michael Binder and AECL President & CEO Hugh MacDiarmid, outlines the administrative framework, milestones and service standards for the licensing activities required for restarting the NRU reactor after the repair of the reactor vessel. The Protocol was revised on January 11, 2010 and replaces the previous version. A link to the revised Protocol is available at
www.NRUCanada.ca.
The 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.
Posted 21/01/2010
Atomic Energy of Canada Limited (AECL) is a leading-edge nuclear technology and services company providing services to utilities worldwide. Over 5,000 highly skilled employees enthusiastically deliver a range of nuclear services: from R&D support, construction management, design and engineering to specialized technology, waste management and decommissioning in support of CANDU reactor products.
AECL is committed to supporting its Canadian and international customers in all aspects of nuclear power technology management. The company provide on-site expertise, closely supported by our nuclear science laboratories, testing capability and engineering facilities. CANDU reactors supply about 16% of Canada's electricity and are an important component of clean-air energy programs on four continents.
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