INTERNAL PUMP FOR NUCLEAR REACTOR AND ITS INSTALLATION METHOD

PROBLEM TO BE SOLVED: To seat a diffuser of an internal pump to an internal pump nozzle for a nuclear reactor pressure vessel without biting any clad particle. SOLUTION: The inside of a stretch tube 2 is closed by a seal device 14 as shown in Figure a and hung above the internal pump nozzle 5 of the nuclear reactor pressure vessel 1. Through the condition shown in Figure b, a diffuser boss part 4a is seated on the upper end face of the internal pump nozzle 5 as shown in Figure c. Before seating the diffuser boss part 4a, clean water is injected into a casing 7 from a nozzle 17 so that the water is discharged to a flow passage 13 between the lower end face of the diffuser boss part 4a and the upper end face of the internal pump nozzle 5 via a flow passage 12 formed between the outer circumference face of the stretch tube 6 and the inner circumference face of the internal pump nozzle 5. In this way, cladding existing between the lower end face of the diffuser boss part 4a and the upper end face of the internal pump nozzle 5 is washed out, and biting of the cladding is prevented when the diffuse boss part 4a is seated onto the internal pump nozzle 5. COPYRIGHT: (C)2005,JPO&NCIPI