THERMAL-SHOCK EXPERIMENTS ON THE HDR PRESSURE-VESSEL

Within the HDR-Safety Program cracks in the HDR pressure vessel were generated and propagated by cyclic and monotonic thermal shock loadings. After various test stages the damaged zones of the RPV were removed and examined both fractographically and metallographically. These post-test examinations showed, that during the cyclic thermal shock test series crack growth has occurred, which could be assessed to the safe side by the ASME-Standard. The long time thermal shocks instead yielded no stable crack growth. The reason for this is the crack depth used for the pre-test assessments, as was found by nondestructive examinations and which was nearly twice as high as found in the post-test fractographical examinations.