Framatome Gmbh

Jean P Dworaczek

Daniel Grypczynski

To repair the internal thread (2b) of a large diameter orifice, an added thread is screwed into the orifice in a form wound on a threaded part of the surface of a drum screwed into an internally threaded centering ring engaged in the entry part (2a) of the orifice (2). The thread is laid against the internal thread (2b) and fastened in place by installing a pin passing through the thread and engaged in the wall of the orifice (2). The process is used for repairing the internal threads of orifices (2) machined in the flange of a pressurized-water nuclear reactor vessel, allowing the vessel cover to be bolted down sealingly.

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Le Breuil, France

Jean P Dworaczek