Fifty years of progress in reactor safety

This paper chronicles the major watershed occurrences in the evaluation of current reactor safety principles and concepts. The author covers such issues as the development of siting criteria in the early 1960s, development and design of engineered safety features and emergency cooling systems (ECCS), core meltdown scenarios, anticipated transients without scram (ATWS) issues, WASH-1400 Reactor Safety study employing probabilistic risk assessment (PRA) approaches, early PRAs conducted, development of safety goals in the 1980s, and reliability of AC power. Perhaps three of the most significant events related to operating reactors that occurred near the end of the 50-yr period were recognition of the problems of aging, completion of the NUREG-1150 study, and the development of a program on severe accident management.