Information needs and instrument availability for accident management : Application to YGN 3 and 4

This paper introduces the five-step methodology for identifying information needs and assessing instrument availability during the course of severe in nuclear power plants. The methodology is applied to the Yonggwang (YGN) 3 and 4 to shed light on accident management. It constructs three safety objective trees to prevent the reactor vessel failure, to prevent the containment failure, and to mitigate the fission product release from the containment. The study assesses information needs and instrument availability under severe conditions for preventing the reactor vessel failure of YGN 3 and 4, and recommends additional instruments that may prove to be vital importance in managing the accident. 6 refs., 6 figs., 3 tabs. (author)