MARKING DEVICE FOR MEASURING RESIDUAL STRESS OF METALLIC PIPE FOR NUCLEAR REACTOR, AND METALLIC PIPE RESIDUAL STRESS MEASURING METHOD USING THIS DEVICE

摘要

PROBLEM TO BE SOLVED: To easily and rapidly measure residual stress of a nozzle part of an upper cover of a reactor container by pressing a marker head part with a plurality of pressure elements of polygonal pyramid shape fixed thereto with specified spaces, to a pipe wall. SOLUTION: A plurality of pressure elements 1 of polygonal pyramid shape are fixed to a marker head part 2 with specified spaces. Head part drive mechanism 3 moves the marker head part 2 so as to protrude outward in the radial direction of a metallic pipe P1 and presses the pressure elements 1 to apply marks on a pipe wall Pg. An operating part 5 supports the head part drive mechanism from the outside through a rod 4 and operates it. Distance between two points can therefore be marked accurately on the inner surface of the metallic pipt P, and the distance between the marks is precisely measured by a measuring microscope or the like after the release of stress. The measured value is compared with the distance between the tips of the pressure elements 1. Residual stress can therefore be measured easily and rapidly within the limited time by remote operation.