秦山核电厂SGTR事故及其处置研究

用ＲＥＬＡＰＳ／ＭＯＤ２程序和ＭＡＲＣＨ３程序对秦山核电厂多种假想ＳＧＴＲ事故及其所致严重事故进行了计算，分析了主要事故序列的事故进程，估算了严重事故下的熔堆时序，探讨了一些有效的事故处置措施及其干预效果。

STUDY ON SGTR ACCIDENTS AND ACCIDENT MANAGEMENTS FOR QINSHAN NPP

SGTR accident is one of the most frequent major accidents, in which operators have to intervene immediately in order to prevent the broken SG from overfilling. If the broken SG overfill leads to the safety valve stuck open, severe accident may occur.RELAP5/MOD2 and MARCH3 codes are applied to process analysis of Qinshan Nuclear Power Plant SGTR accidents and severe accidents initiated by SGTR. Time sequences for core melting are estimated. Some accident managements and their effects are discussed. The analysis results by the codes show that the following accident sequences may lead to coremelt, such as SGTR with broken SG safety valve stuck open, SGTR with loss of AKW, more ruptured tubes SGTR with failure of safety injection system, and SGTR with failure of both SI and AFW.The experiences of accident managements show that the coremelt can be prevented by means of depressurizing RCS by feed - bleed of intact SG, by openning pressurizer PORVs manually, or by primary system bleed with secondary system feed. The probability for SGTR events leading to coremelt can be considerably reduced by the above managements.