| 摘要 |
PROBLEM TO BE SOLVED: To realize quick positioning, movement and highly efficient accurate ultrasonic flaw detection by mounting travel guide means on the opposite ends of a horizontal base part moving in the vertical direction such that the travel guide means can abut against the intermediate drum part of a shroud and the inner wall of a pressure vessel. SOLUTION: An ultrasonic flaw detector 1 is lowered into an environmental space between a reactor pressure vessel 31 and the upper drum 13a of a shroud. A vertical direction probe translation mechanism 19 and a telescopic structure 18 are then operated to bring an ultrasonic flaw detection probe 26 at the vertical part 4 into contact with the upper drum 13a of a shroud and the side face of an intermediate ring 13b of the shroud. Furthermore, an ultrasonic flaw detection probe 41 at the horizontal part 5 is brought into contact with the lower surface of the intermediate ring 13b. Subsequently, the vertical direction probe translation mechanism 19 is operated to move a probe tool 20 up and down in order to inspect the welded part between the upper drum 13a and the side face part of the intermediate ring 13b. Furthermore, a probe tool 30 is moved horizontally by a horizontal direction probe translation mechanism 29 in order to inspect the intermediate ring 13b and the welded part. |
