Importance

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Abstract

The plugs are used to close the main steam lines of a boiling-water reactor when the reactor is shut down for maintenance, testing and refueling. The plug utilizes an elongated rubber member which is compressed by axial compression in order to form a seal which will hold the plug in place despite the presence in the steam line of substantial isolation valve test pressures which might force the plug out. Preferably, plates covering portions of the rubber are used to provide a long-lasting solid surface to grip the inside wall of the pipe. A device is provided for the remote installation of the plug so as to minimize the exposure of workers to radioactivity in the reactor vessel. The installation device includes remotely controllable structure for compressing the rubber member of the plug. In one embodiment, the compression structure includes a set of impact wrenches for turning a nut on each of several bolts which are used to compress the rubber member of the plug. In another embodiment, pressurized hydraulic fluid is supplied from a remote pump and is used to drive pistons to compress the rubber member. The installation device is remotely attachable to and detachable from the plug.

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First Claim