METHOD FOR ANNEALING WELDED ZONE OF NOZZLE STUB AND HEATING DEVICE FOR ANNEALING

摘要

PPROBLEM TO BE SOLVED: To eliminate thermal stress strain in the weld zone of a large-sized apparatus (for example, an evaporator), at which the nozzle stub has been welded, by reliably annealing the weld zone at a uniform temperature. PSOLUTION: A drain hole 50 is formed in a drum 11 of an evaporator of a nuclear power plant, and the nozzle stub 60 is welded to the outer wall side of the drain hole 50 to form a weld zone 70. In order to eliminate the thermal stress strain in the weld zone 70 and the peripheral regions, the annealing is performed by: heating the portions from the outer wall side by using an outside heater 80; and simultaneously heating the portions from the inside by inserting the rod type heating device 100 for annealing into the drain hole 50 and using the heating device 100 for annealing. The heating device 100 for annealing includes a heater part 101 which is a heating part, and a plugging member 102 at the top. The plugging member 102 prevents the heat enhanced by heating from dissipating by air convection to improve heating efficiency. PCOPYRIGHT: (C)2008,JPO&INPIT