Cascaded control of power input and welding temperature during sealing of spent nuclear fuel canisters
The friction stir welding procedure to seal copper canisters requires variable power input throughout the 45 minute long weld cycle to keep the welding temperature within the process window. This is due to variable thermal boundary conditions throughout the weld cycle which, together with fast disturbances in the spindle torque, requires control of both the power input and the welding temperature
