Deformation Measurements on Pipework Components Up to 650 deg C for Service Life Monitoring

摘要

Thermal material strain is causing restraint stresses and, as a result, considerable structural stresses in pipework systems with high operating temperatures. In this case deformation is taken up by the bends which bend relatively easily compared to the straight piping. The design requirements specified for the fast sodium cooled reactor (SNR-300) have the effect that the temperature-strain controlled stresses are not the most important load parameter. Original SNR-300 pipe bends are tested in an experiment close to reality to demonstrate the operating efficiency of the main coolant pipework and to verify the design. Using a newly developed global strain measuring device for monitoring the service life, it is possible to establish the residual life of a pipe bend. This knowledge should improve plant safety and offer advantages with regard to costs. Apart from the usual operating parameters, internal pressure, temperature and time, relevant for the full use of the service life of a pipe bend the deformations imposed on the pipe bend by restraint of the adjacent pipework are of decisive importance. These data can be verified by local strain measurements until failure of the test pipe bend in conjunction with inelastic calculations. (ERA citation 12:009120)