Patent ID: 8514998
Filing Date: 2013-08-20
Classification: C21D,Y02P

Abstract:
1. An induction heating stress improvement method in a nuclear power plant including a recirculation inlet nozzle having an annular clearance, the recirculation inlet nozzle including an inner surface of piping having a fluid therein, the method comprising: providing a header tank comprising at least one cooling nozzle and a thermometer; installing the at least one cooling nozzle of a header tank within a range in a clockwise direction from one of a point at −45° from a horizontal position at 9 o'clock to a point at +45° from a horizontal position at 9 o'clock or a point at −45° from a horizontal position at 3 o'clock to a point at +45° from a horizontal position at 3 o'clock within the annular clearance of the recirculation inlet nozzle, supplying cooling water by the cooling nozzle to the inner surface of piping of the recirculation inlet nozzle, and verifying a cooling effect with respect to the inner surface of the piping by measuring a temperature of the fluid in the piping that has been raised by external heating of the recirculation inlet nozzle when applying the induction heating stress improvement method to the piping, and wherein an installation position of the thermometer is deviated from that of the cooling nozzle of the header tank in the peripheral direction by installing the thermometer within a range in a clockwise direction from a point at −45° from a position at 12 o'clock to a point at +45° from a position at 12 o'clock within the annular clearance of the recirculation inlet nozzle.