Application of PAA in EPR Nuclear Power Units

Chen Wen,Wang Zhiwu,Qing Chen,Chen Shijun,Chen Jiefei,Chen Yu,Jiang Hong,Zhang Tao

Table6 TU_jkCalculation methods of different unavailabilitytypes[7]

No.	Unavailability type	Failure unavailability time	Failure unavailability probabilistic
1 Category: direct shutdown	1a: automated shutdown	TU_jk = t_{100→0%PNshutdown}+ t_condition+ t_preparation+ MTTR+ t_{re-identification}+ t_reach100%PN	X_jk = λ_jk × TU_jk
	1b: hand-operated shutdown	TU_jk = t_{100→0%PNhand-operated}+ t_condition+ t_preparation+ MTTR + t_{re-identification}+ t_reach100%PN
	1c: hand-operated shutdown after power reduction	TU_jk = α·t_diagnosis+ t_{100→0%PNnormal}+ t_condition+ t_preparation+ MTTR + t_{re-identification} + t_reach100%PN
2 Second category: power reduction	2a: maintenance during power reduction	TU_jk = α·(MTTR + t_{re-identification})
2 Second category: power reduction	2b: power reduction to next shutdown	TU_jk =α·t_diagnosis+t_{100→0%PNnormal}+ t_condition+ t_preparation+MTTR + t_{re-identification}+t_reach100%PN
3 Third category: OTS requirements	3a: failures that cannot be repaired in RP mode of operational equipment	TU_jk = t_{100→0%PNnormal}+ t_condition+ t_preparation+ MTTR + t_{re-identification}+ t_reach100%PN
3 Third category: OTS requirements	3b: stand-by component failure	TU_jk_{= 1} ≤ t_{100→0%PNnormal} + t_condition + MTTR_i + t_{re-identification} + t_reach100%PN