Systems and methods for application of stress corrosion cracking resistant cold spray coatings

A method of forming a coating on a hazardous waste canister (HWC) positioned in a chamber of an overpack container, the chamber of the overpack container being defined by an inner surface of the overpack container, the HWC having a perimeter wall with an outer surface positioned in opposition to the inner surface of the overpack container to define an annular gap between the outer surface of the perimeter wall and the inner surface of the overpack container, the gap extending from a bottom of the HWC to a top of the HWC, the method comprising:

• providing an application system including:
• a cold spray apparatus configured to generate a high-pressure gas flow carrying particles, the cold spray apparatus including a nozzle having an outlet from which a stream of gas and powder particles exits the cold spray apparatus;
• and
• a mobile applicator apparatus configured to carry at least the nozzle of the cold spray apparatus, the mobile applicator apparatus including a mobile base with a frame and a plurality of wheels rotatably mounted on the frame to contact and traverse the outer surface of the perimeter wall of the HWC;
• accessing the outer surface of the perimeter wall of the HWC by positioning the mobile applicator apparatus in the annular gap between the outer surface of the perimeter wall of the HWC and the inner surface of the overpack container;
• identifying a compromised region on the outer surface of the perimeter wall of the canister for material application to the outer surface of the perimeter wall;
• positioning the nozzle of the cold spray apparatus in the annular gap between the inner surface of the overpack container and the outer surface of the perimeter wall of the HWC at a first position adjacent to the compromised region of the outer surface of the perimeter wall;
• emitting, at the first position of the nozzle in the annular gap, a substantially linear flow of particles of a powder from the nozzle of the cold spray apparatus toward an area in the compromised region of the outer surface of the perimeter wall to impact the particles of the powder against the area in a manner effective to cause the particles of the powder to bond to the outer surface of the perimeter wall to produce a coating on the area of the compromised region of the outer surface of the perimeter wall;
• and
• moving the nozzle of the cold spray apparatus in the gap with respect to the outer surface of the perimeter wall from the first position to a second position adjacent to the compromised region of the outer surface of the perimeter wall;
• emitting, at the second positon of the nozzle in the annular gap, a substantially linear flow of particles of the powder from the nozzle of the cold spray apparatus toward an additional area in the compromised region of the outer surface of the perimeter wall to impact the particles of the powder against the additional area in a manner effective to cause the particles of the powder to bond to the additional area of the outer surface of the perimeter wall to produce a further coating on the additional area of the compromised region of the outer surface of the perimeter wall;
• wherein said moving of the nozzle of the cold spray apparatus is performed without moving the HWC with respect to the overpack container.