Cold spray copper coating application to the weld closure zone of used nuclear fuel containers

Since 2011, NWMO has been developing copper coatings for the purpose of providing corrosion protection to steel used nuclear fuel containers. Through a series of initiatives in cold spray, electrodeposition and weld cladding methods, copper coatings ranging in thicknesses of 3 to 10 mm have been applied to a series of steel substrates. Components have progressed from small coupons to full sized parts. NWMO has determined that both electrodeposition and cold spray processes will be used to copper coat the UFC. Electrodeposition will be used for copper coating the 'factory' supplied UFC components (shell, lid). This process is a well-established, straightforward industrial technique well suited to the UFC geometry under conventional fabrication conditions. The cold spray process is to be used for coating the closure weld upon final assembly; this process is well suited to automated, robotic application in a radioactive environment. In the most recent investigation, cold spray copper has been applied across mockup and actual weld zones to complete the coating of used fuel containers. Within this work, cold spray coating parameters must be sufficiently rugged to produce high quality coatings across a region including electrodeposited copper on both edges (transition zone), container steel and welded steel. (author)