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AssigneeABB Atom AB
InventorsBo Borrman, Hans Kornfeldt, Lars-Ake Kornvik, Per Sundlof, Lars Tornblom
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A method for sealing a leak between a control rod drive (CRD) stub tube (3) arranged in a reactor wall (2) and a tubular CRD housing (1) extending through the CRD stub tube (3) and the vessel wall (2). According to the invention, this sealing is obtained by deforming a suitably shaped element of memory metal below the transition temperature of the memory metal in such a way that it can be inserted, in the form of a sleeve (5) or a ring, into or around the CRD housing (1) where said housing passes through the vessel wall (2), or alternatively replace part of the CRD housing (1) at the passage through the vessel wall (2). Then when the memory metal is heated to above the transition temperature, it strives to resume its original shape which shall then have been such that the desired seal is obtained.
A method for sealing a leak between a CRD stub tube (3) arranged around a hole through a reactor vessel wall (2) and a tubular CRD housing (1) extending through the CRD stub tube (3) and the vessel wall (2), characterized in that part of the CRD housing (1) which is positioned in the hole is cut away and removed;
A method for sealing a leak between a CRD stub tube (3) arranged around a hole through a reactor vessel wall (2) and a CRD housing (1) extending through the CRD stub tube (3) and the vessel wall (2), characterized in that inside that part of the CRD housing (1) which extends through the hole in the vessel wall (2) there is provided an internal slot (7) around the internal circumference of the CRD housing (1), whereupon a second sleeve (8) of memory metal with a larger outside diameter than the largest diameter of the slot (7) at a temperature above the transition temperature of the memory metal is deformed below the transition temperature into a smaller outside diameter than the inside diameter of the CRD housing (1), whereupon the sleeve (8) is inserted into the slot and heated above the transition temperature such that the sleeve (8) sealingly presses the outer wall of the CRD housing (1) against the vessel (2).
A method for sealing a leak between a CRD stub tube (3) arranged around a hole through the reactor vessel wall (2) and a tubular CRD housing (1) extending through the CRD stub tube (3) and the vessel wall (2), characterized in that on the outside of the reactor vessel there is provided an external slot (9) in the vessel wall (2) around the CRD housing (1);
Dependencies are inferred from the claim text.