DERIVATION OF TRANSVERSE TENSILE PROPERTIES OF ALLOY 690 STEAM GENERATOR TUBES USING RING-TENSILE SPECIMEN AND FINITE ELEMENT ANALYSIS

摘要

Transverse tensile properties of the Alloy 690 steam generator tube used in Korean PWR(pressurized water reactor) nuclear power plant is one of the main properties to analyze creep rupture caused by the hoop stress in the severe accident conditions. Transverse tensile properties of steam generator tubes cannot be obtained directly machined from the tubes and it is also difficult to make miniaturized flat tensile specimens due to their geometry limitations. The ring-tensile specimens are widely used to measure the tensile properties in the circumferential direction, but membrane and bending stresses are mixed in the ring-tensile specimen during the test due to the shape of ring-tensile specimens. Therefore, obtaining the transverse tensile properties need the inverse analysis using finite element analysis and optimization process. In this study, ring-tensile tests were carried out using 3-piece loading mandrel. The stress-strain curve of ring-tensile specimen in transverse direction is derived by comparing the load-displacement curves of the finite element analysis with those of test. The load-displacement curves from tests agree well with the finite element results. Use of finite element analysis and optimization process as used in this work is effective to predict the transverse tensile properties of ring-tensile specimen.