Emergency Operating Procedure

EOP 7 Inadvertent Trip of Containment Isolation System Revision 1 2/6/64

A. Symptoms

1. AMBER pushbutton of CONTAINMENT PRESSURE LOW RANGE pushbutton station probably will illuminate.
2. HIGH PRESSURE CONTAINMENT alarm most probably will not alarm.

3. The following valves will close; their indicating lights change from GREEN to AMBER.

	 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

4. The following annunciators will alarm immediately:

Low flow cooling water primary pump PS-P1
Low flow cooling water primary pump PS-P2
Low flow cooling water primary pump PS-P3
Low flow cooling water primary pump PS-P4
Low flow primary letdown.

B. Immediate Action

1. Evaluate alarms and indicators to determine that the containment isolation system has tripped.
2. Check containment pressure indication, and primary and secondary pressures and water levels. IF normal, depress the OPEN pushbutton for the containment isolation system valves. If valves do not open continue this procedure.
3. Primary pumps can be operated for 15 minutes at full speed or 30 minutes at half speed without cooling water flow.
4. Charge pumps should be stopped when pressurizer level has risen 15 inches (will probably take about 15 minutes). If the malfunction has not been corrected yet, scram the reactor and start the emergency cooling system.
5. Send an operator to the emergency cooling panel to operate the emergency cooling system.

C. Follow-Up Action

When it has been determined that the containment isolation system malfunctioned, the cause of the malfunction should be corrected and then plant operation resumed.

D. Discussion

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.

Table I CONTAINMENT ISOLATION SYSTEM TEST

SOLENOID SHUT-OFF VALVE FOR PNEUMATIC INSTRUMENTATION LINES

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.

Table II CONTAINMENT ISOLATION SYSTEM TEST

SYSTEM SHUT-OFF VALVES

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.