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).
A detailed analysis of the Non Destructive Examination (NDE) data collected to date continues. Results of this analysis have been provided to the vendors to support their tooling development. The NDE team has undertaken high-resolution scans of the vessel using the Mark I tool. The deployment of the new Mark II tool is scheduled for mid August. It will allow us to complete the investigation of areas that were otherwise not accessible.
Work continues with specialized vendors on proving repair tooling designs and fabrication of the equipment. Based on the results from the data collected through NDE, AECL has selected “weld build-up” as the preferred repair technique. This technique builds up the thickness of the metal by fusing weld rod material to the surface. Mechanical repair may also be used if required for specific conditions.
Qualification testing of the repair tools will be required following manufacture. Testing of the repair process and special tools will be carried out on the full height mock-up assembled in the former NRX reactor. The mock-up will be used to train employees on the specialized repair tools.
Evidence collected to date continues to support AECL’s belief that the necessary vessel repairs can be made and that NRU will be 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.
AECL continues to work very closely with the Canadian Nuclear Safety Commission (CNSC), and CNSC safety inspectors are directly involved at the Chalk River site. There is no threat to workers, the public, the environment or nuclear safety related to this event. More information on the repair and status updates on the NRU is available at http://www.nrucanada.ca/