'Warm pre-stress effect' WPS - consideration when assessing integrity

摘要

It has been known for some time that the failure in the transition area and lower shelf of fracture toughness is not only determined by the amount of load but also by the load history, i.e. the so-called "load path". The generally higher breaking load after previous load at higher temperatures, the warm pre-load is called warm pre-stress (WPS) in comparison to EIC tests (load at test temperature). With the procedure described it is possible to use the warm pre-stress effect for quantifying cooling-down transients in LWR reactors, i.e. to quantity the safety margin against initiation expressed in reloading.