Method and apparatus for tube expansion

An apparatus for radially expanding a tubular member concentrically located within a tube of a nuclear steam generator and having an annular space therebetween, comprising a first end cap, a second end cap spaced from the first end cap, a post rigidly connected between said end caps, means for fixedly connecting the caps relative to each other and the post in a spaced relationship, an expandable bladder connected to and extended between the caps and around the post to define a closed space therewith, a solid propellant contained within the closed space, the bladder being a flexible and resilient material, the end caps being insertable within the tubular member with the first end cap and the second end cap being radially spaced from the tubular member, the bladder being rapidly expandable from a position out of contact with the tubular member into contact with the tubular member responsive to the explosive generation of gas within the closed space upon ignition of the propellant and contractable out of contact with the tubular member responsive to venting of the gas from the closed space, means for igniting the propellant to generate gas and radially expand said bladder and the tubular member to effect contact between the tubular member and the tube, and means for venting the gas.