PURPOSE: To absorb thermal expansion of a track and to increase strength against external force by pinning a supporting body for a pressure vessel and the circumferential track by means of many pieces of connecting bars disposed at prescribed intervals and with inclination.
CONSTITUTION: In a track for ultrasonic flaw detection of the circumferential weld zones in the bottom end parts of a pressure vessel for nuclear reactors, a circumferential track 5 installed in accordance with the weld line and a supporting body 3 for the pressure vessel are connected by means of many pieces of connecting bars 8. So as to deal with the thermal expansion of the track, the bars 8 are connected to the track 5 and the body 3 by means of rotatable pins 9, 10 at prescribed angles with respect to a radial direction and at prescribed intervals. Since the circumferential track 5 which is easy to install and support absorbs thermal expansion and is firmly fixed, the track has increased strength against external force such as earthquakes.
ASANO KUNITAKA
NARUSE AKISUKE
HITACHI ENG CO LTD