Atomic Energy of Canada Limited has taken a step towards repairing its NRU reactor, by simulating the repair at a mock-up facility. The reactor has been shut down since May when a heavy water leak was detected.

AECL said on 11 November that it has installed the first set of welding tools and equipment in the full height mock-up at Chalk River's NRX facility. The NRX mock-up allows the repair team to simulate the real repair on the NRU vessel.

Welders are practicing using the tools to repair simulated areas of corrosion located 9m below their access point, with the only available visuals of the repair site displayed on a video monitor.

Once the welders have completed simulation training on the use of the tools, the welding equipment will be disassembled and moved to the NRU reactor in preparation for the next major activity, the start of in-vessel repair.

In a statement AECL said that the “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.” Based on the evidence available the reactor, which supplies over 50% of the world’s radioisotopes, is expected to return to service during the first quarter of 2010.