The issue of CCF （common cause failure） in digital I ＆ C （instrumentation and control） systems is of great interest because an increasing number of such systems are implemented in nuclear power plants. For the mi...The issue of CCF （common cause failure） in digital I ＆ C （instrumentation and control） systems is of great interest because an increasing number of such systems are implemented in nuclear power plants. For the mitigation of ATWS （anticipated transients without scram） as well as CCF within the PPS （plant protection system） and the ESF-CCS （engineered safety feature-component control system）, the ADPS （advanced diverse protection system） has been developed by KEPCO E ＆ C （KEPCO Engineering and Construction） Company for new nuclear units in Korea. As compared to the DPS （diverse protection system） design of APR1400, the ADPS has a diverse safety injection function considering a LBLOCA （large break loss of coolant accident） concurrent with the CCF of the PPS and ESF-CCS. Besides the function of SIAS （safety injection actuation signal） initiation, several CCF avoidance features, such as the changes of software design classification, communication methods, equipment platform, and man-machine interfaces, are introduced to enhance the reliability of the ADPS. In addition, the ADPS has recently incorporated four redundant channels with 2-out-of-4 voting logics to enhance its fault tolerant capability. Therefore, it is expected that the ADPS can provide an enhanced reliability regarding possible CCFs in the safety-grade digital I ＆ C systems as well as the ADPS itself.展开更多
文摘The issue of CCF （common cause failure） in digital I ＆ C （instrumentation and control） systems is of great interest because an increasing number of such systems are implemented in nuclear power plants. For the mitigation of ATWS （anticipated transients without scram） as well as CCF within the PPS （plant protection system） and the ESF-CCS （engineered safety feature-component control system）, the ADPS （advanced diverse protection system） has been developed by KEPCO E ＆ C （KEPCO Engineering and Construction） Company for new nuclear units in Korea. As compared to the DPS （diverse protection system） design of APR1400, the ADPS has a diverse safety injection function considering a LBLOCA （large break loss of coolant accident） concurrent with the CCF of the PPS and ESF-CCS. Besides the function of SIAS （safety injection actuation signal） initiation, several CCF avoidance features, such as the changes of software design classification, communication methods, equipment platform, and man-machine interfaces, are introduced to enhance the reliability of the ADPS. In addition, the ADPS has recently incorporated four redundant channels with 2-out-of-4 voting logics to enhance its fault tolerant capability. Therefore, it is expected that the ADPS can provide an enhanced reliability regarding possible CCFs in the safety-grade digital I ＆ C systems as well as the ADPS itself.
