Analysis of Several Cases of MSGTR Events in Korea Next Generation Reactor

摘要

A multiple steam generator tube rupture (MSGTR) event has never occurred in the history of commercial nuclearrnreactor operation while single steam generator tube rupture (SGTR) event is reported to occur every two years. As there is nornhistory of MSGTR event, the understandings of transients and consequences of this event are not so much. In this study, arnpostulated MSGTR event in Korea Next Generation Reactor (KNGR) is analyzed using thermal-hydraulic system code. ThernKNGR is a two-loop, 1000 MWe, PWR supposed to be built in 2009. RELAP5/MOD3 is used in this study.rnEffects of rupture location in a tube and selection of steam generator affected are tested. An analysis is carried outrnfor five rupture locations in a tube. Main steam safety valve (MSSV) lift time is found to be the smallest when tubes arernruptured near hot-leg side tube sheet while largest when tube top is ruptured. The MSSV lift time for rupture at tube-top isrnevaluated as 24.5% larger than that for rupture at hot-leg side tube sheet. In order to test how selection of steam generatorrndamaged affects MSSV lift time, four cases are analyzed. The results show that the cases that both of two steam generators arernaffected allow longer time for operator action compared with the case that a single steam generator is affected.