CRACK GROWTH SENSOR AND CRACK GROWTH QUANTITY MEASURING SYSTEM USED FOR ENVIRONMENTAL EVALUATION OR THE LIKE

摘要

A crack growth sensor placed in an environment such as in a nuclear reactor to have crack growth promoted therein, wherein a sensor element that undergoes crack growth is in the form of, for example, a hollow cylinder or plate, constructed such that the sensor element is subjected to a tensile load axially applied thereto at its axially opposite ends or a torsion load applied thereto. This sensor element is formed with a crack initiation point, for example, a slit, groove or pinhole, where stress concentration occurs owing to the tensile load or torsion load. For example, a core or/and a spring having a compression load applied thereto are inserted in a cylinder that serves as the sensor element and the reaction to the compression load thereon is supported by caps attached to the opposite ends of the cylinder, thereby causing stress concentration that promotes crack growth to occur at the crack initiation point in the sensor element.