ANALISIS SKENARIO KEGAGALAN SISTEM UNTUK MENENTUKAN PROBABILITAS KECELAKAAN PARAH AP1000

Abstract

Fukushima accident has shown that severe accident could be occurred, therefore it is important to analyze safety level of nuclear power plants. Based on the recommendations of IAEA expert mission after the Fukushima accident, necessary effort to minimize severe accident by optimizing cooling process. On the safety concept of nuclear facility especially power reactor has been applied defence in depth (DiD) concept. These concept consists of five defense levels which is to prevent and to reduce fission product release to the public and the environment when the power reactor accident happen. On the reactor has been designed system or action that have function to overcome with each those levels. The objective of this paper is to determine severe accident probability by system failure scenario on the cooling process in the reactor. The AP1000 is chosen as the reference plant to be evaluated, because currently this reactor is being built in many countries. The scenario is carried out by combining several system failures included in DiD level 2 and 3. System failure is evaluated by fault tree analysis using SAPHIRE code version 6.76. The analysis results show that the failure probability of system in the DiD level 2 and 3 AP1000 is still below the IAEA criteria limit that is less than 10^-2, as well as the probability of severe accident is 6.17 x 10^-10. Based on this analysis, it can be concluded that the safety level of AP1000 is high enough, because through system failure scenario is obtained the probability of severe accident is very small.