MECHANICAL PROPERTIES OF BOLTS REMOVED FROM OPERATING US PWRS PROPRIETES MECANIQUES DE VIS EXTRAITES DE REP AMERICAINS EN EXPLOITATION

摘要

As part of the baffle/former bolt replacement projects for the two lead domestic plants ultrasonic testing (UT) data and tensile testing of selected baffle-former bolts in the field were performed. The results from this testing are reported in this paper. In addition, laboratory UT testing and tensile testing of bolts sent to the hot cell facility are compared to the field test data. The conventional, subsize tensile specimen data and some toughness data are reported and compared to the field information. The NDE data for those bolts which have internal hex heads and are fabricated from 347 annealed stainless steel appears to give a conservative estimate of the existence of cracks since no cracks were found in some bolts in areas where the UT signal indicated degradation. Significant ductility remained in the bolts even when highly irradiated. The small specimen tensile data is comparable to the full bolt data with slightly less total elongation. A loss of toughness was measured on bolt shaped non-standard specimens.