PP-1V WL-1V CW-206V PR-2V PR-9V PP-2V SA-1V CW-207V PR-3V WL-20V PP-3V SA-4V CW-208V SS-21V PP-4V SA-45V CW-209V SS-22V PP-6V CW-201V CW-210V SL-8V (PP-7V CW-202V PD-20V PE-1V Close (PP-8V CW-203V PD-21V PE-2V Slowly (PP-57V CW-205V PD-39V PE-3V
When it has been determined that the containment isolation system malfunctioned, the cause of the malfunction should be corrected and then plant operation resumed.
The main consequences of a containment isolation system trip is the loss of primary system letdown flow and the loss of CW flow to components inside the containment vessel. Serious consequences resulting from this are prevented by stopping the charge pumps to stop makeup to the primary system and by shutting off the primary pumps and starting the emergency cooling system.
The table on the following pages lists the valves affected by the containment isolation system and the effect of a system trip on each valve.
Diaphragm Solenoid Valve Valve Effect on Plant CC-1V Isolate PXP-CC7 when containment pressure reaches 10 pisg. CC-19V] CC-26V] Simultaneous closing of both valves will close vent lines from all the diaphragm operated valves in the containment vessel. PP-7V CC-18V Shut-off valve for air supply to positioner. PP-7V closes slowly as air bleeds off. CC-5V Signal air shut-off to positioner. CC-24V Shut-off valve for positioner vent. PP-8V CC-17V Shut-off valve for air supply to positioner. PP-8V closes slowly as air bleeds off. CC-6V Shut-off valve for signal air to positioner. CC-25V Shut-off valve for positioner vent. PP-1V] CC-2V Shut-off valve for air supply to diaphragm PP-3V] operator. PP-1V and PP-3V close. PP-2V] CC-3V Shut-off valve for air supply to diaphragm PP-4V] operator PP-2V and PP-4V close. PP-6V CC-4V Signal air shut-off valve. PP-6V closes. PP-2V CC-9V Signal air shut-off. Loss of pilot actutated pressure relief valve. PR-2V closes. PR-9V CC-11V Air supply shut-off valve. PR-9V closes. PE-1V] CC-7V ] Signal air shut-off. PE-1V, PE-2V and PE-3V clsoe. PE-2V] CC-8V ] PE-3V] CC-27V] WL-1V CC-16V Air supply shut-off. WL-1V closes. SA-1V CC-12V Air supply shut-off valve. SA-1V closes.
Valves Which Close Effect on Plant CW-207V] Close cooling water from the primary pumps. CW-208V] CW-209V] CW-210V] CW-205V] Close cooling water from the containment cooling coils. CW-206V] CW-201V] Close cooling water from the purification letdown coolers. CW-202V] CW-203V Close cooling water from the reactor shield tank. PD-20V Close drain from containment drain tank. PD-21V Close drain from bottom of containment. PD-39V Close overflow drain from ECT. SS-21V] Close continuous blowdown lines from boilers. SS-22V] SL-8V Close vent line from containment. CC-29V] Close hydrogen detection system for the containment vessel. CC-30V] SA-45V Close sampling line from purification letdown system. PP-1V, 3V] Close purification valves around letdown coolers. PP-2V, 4V] PP-57V Close purification letdown line. CC-401V] Hydraulic system isolation valves CLOSED. CC-405V] No immediate effect. Possible loss of oil CC-406V] from drain header connection if condition CC-404V] exists for extended period.