Containment Depressurization Capabilities of Filtered Venting System in 1000 MWe PWR with Large Dry Containment

Table 5

Containment event tree of OPR1000.

CET Heading	Definition	Subbranch	Effect on; CFVS	Remark
RCSFAIL	RCS fail before RV fail	No fail; HL Break; SGTR	—; —; No	Bypass
MELTSTOP	Core melt progression Stopped before RV fail	Melt stop; RV rupture; CFBRB	—; —; Yes
ALPHA	ALPHA mode containment failure	No fail; Fail	—; No	Early CTMT failure
CR-EJECT	Amount of corium ejected out of cavity	High, medium, low	—
CF-EARLY	Early containment failure	No fail; Leak/Rupture	—; No	Early CTMT failure
CS-LATE	Recirculation spray failure	No fail, fail	—
EXVCOOL	Debris cooled ex-vessel	No cooled, cooled	—
CF-LATE	Late containment failure	No fail; Leak/rupture	—; Yes