ML19323A953

Emergency Procedure DGA-5,Revision 4, Low Reactor Water Level.

ML19323A953
Person / Time
Site:	Dresden
Issue date:	01/26/1980
From:	COMMONWEALTH EDISON CO.
To:
Shared Package
ML17192A611	List: ML17192A610 ML17192A671 ML17192A672 ML17192A673 ML17192A674 ML17192A675 ML17192A676 ML17192A677 ML17192A678 ML17192A679 ML17192A680 ML17192A681 ML17192A682 ML19323A953
References
DGA-5, NUDOCS 8005080499
Download: ML19323A953 (7)

Text

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., 80 eso8o IDdA 5 Jan. 980 LOW REACTOR WATER LEVEL A. SYMPTOMS

1. Alams ,

a .- FX VESSEL LOW LEVEL 902-5 (903-5).

b. REACTOR FEED PUtiP SUCTION LOW PRESSURE 902-6'(903-6).

c. RFP AUTO TRIP 902-6 (903-6).

d. RFP DISCHARGE LCW PRESSURE 902-6 (903-6).

e. FEE 0 WATER CONTROL VALVE AIR FAILURE 902-5 (903-5).

f. FEECUATER ELECT CONTROL SIGNAL FAILURE 902-5 (903-5).

.g. GROUP 2 ISOL CH TRIP 902-5 (903-5).

h. GROUP 3 ISOL CH TRIP 902-5 (903-5).

2. Feedwater flow less than steam flow with reactor vessel level below nomal and decreasing.

3. Feedwater Regulator Valve failed closed.

4. Inadvertent closure of Isolation Valves in Feedwater Systen.

8. AUT01ATIC ACTI0t!S

1. Reactor scram at +8" indicated.

2. Reactor Feed Punps in RUN00T.

3. Group 2 and 3 Isolations 0 +8" indicated.

4. ECCS initiation 0 -59 inches.

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C. IttttEDIATE OPERATOR ACTIONS NOTE LOCAL ttANUAL control of Feedwater Regulating Valves cay be attenpted at any tice. The pace of the transient will be the detemining factor.

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DGA 5 Revision 4

1. IF Feedwater Regulating Valve has

a. Failed in AUTO -

(1) Take MANUAL control and establish normal water level using more than ene level indication.

(2) IF valve does not respond in PANUAL and level is continuing to decrease, PLACE the other Feedwater Regulating Valve in service and isolate the failed Feedwater Regulating Valve.

(3) IF neither Feedwater Regulating Valve responds in AUTO, take LOCAL MANUAL control of the valve in se rvice.

CAUTION IF reactor scrams or feedwater controls cust be abandoned, ensure the level Setpoint is returned to normal .

NOTE 9

In lieu of the following step, it is possible to adjust recirculation flow until water level settles out at a constant level within the operating range. However, considera-tion cust be given to operating power level, fuel limits, etc. , be fore per-forming such a naneuver.

b. Locked Out -

(1) Reduce Level Setpoint to match level .

(2) Attempt to RESET.

(3) IF valve resets, restore Level Setpoint and level to normal .

(4) IF valve will NOT RESET, restore Level Setpoint to normal, PLACE the other Feedwater Regulating Valve in service and isolate the failed Feedwater Regulating Valve.

(5) IF nef ther Feedwater Regulating Valve responds, l take LOCAL MANUAL con ~ trol of the valve in service. 1

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DGA 5 Revision 4

c. CLOSED -

(1) PLACE the other Feedwater Regulating Valve in se rvice.

(2) Take ffANUAL control of the operable Feedwater Regulating Valve and attempt to restore level.

(3) Isolate the failed Feedwater Regulating Valve.

2. IF Reactor Feed Pumps have tripped

a. Due to low suction pressure -

1 (1) VERIFY Standby Condensate Pump has AUTO started.

(2) VERIFY Standby Reactor Feed Pump has AUTO started.

(3) Correct cause of low suction pressure.

b. Due to other than low suction pressure -

(1) VERIFY that Standby Reactor Feed Pump has AUTO started.

(2) PLACE the control switch for the tripped pump in Pull-To-lock.

(3) Detennine the cause of the trip.

3. Secure blowdown through the Reactor Water Cleanup System.

4. IF reactor water level reaches +8", VERIFY reactor scram.

Follow the Scram procedure (DGP 2-3).

5. IF reactor water level decreases to -59", VERIFY HPCI System initiates.

6. IF high pressure systems fail to initiate or cannot naintain level ,

a. START a Core Spray or LPCI Pump and NOTE If no ECCS is available a Condensate Pump may be used, provid?d the punp is capable of adding water to the ves sel .

b. Manually initiate Auto Blcwdown 120 seccnds af ter level reaches -59". g. , ,,,

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DGA 5 Revision 4 CAUTION IF Yarway reference leg flashing -

occurs during depressurization, Yarway indication may be above

-59" such that LPCI and Core Spray Injection Valves do not open auto-catically.

7. VERIFY that LPCI or Core Spray injection occurs when reactor pressure decreases to 350 psig as indicated by rore than  !

one indication.

D. SUBSE00ENT OPERATOR ACTIONS

1. Station an additional Operator to conitor and control reactor vessel level. Multiple level indications should be utilized.

This Operator shall be assigned no other function.

2. Refer to Procedure To Assure Adequate Core Cooling (DGA-19),

if any of the following conditions occur:

a. Reactor water level indications are continuing to decrease with ECCS operating.

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b. Peactor water level is sustained at a level below the top of the active fuel as indicated by available level indications.

c. Reactor water level indication is unavailable.

d. Less than design flow is indicated on Feedwater or ECC System when design flow is required.

3. IF desired and IF level approaches the High Level Trip setpoints for feedwater and/or HPCI, take MANUAL control of these systems to maintain level and to prevent trips of feed-water and HPCI Systems.

4. IF level has been successfully controlled such that a scram did not occur, continue normal operation and attempt to determine what initiated the transient.

5. IF a reactor scram occurred, VERIFY Group II and III Isolations have occurred.

6. IF -59" level was reached, VERIFY Group I Isolation occurred.

7. IF the Main Condenser is available and plant shutdown is necessary, follow the crocedure for Nornal Shutdown frca Power (DGP 2-1).

8. IF the Main Condenser is not available and shutdown is ON necessary, cooldown using the Isolation Condenser.

JNJ 26 '60 -

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, DGA 5 1 Revision 4 j

9. IF Relief V41ves have been actuated, continually it0t4ITOR and RECORD corus water tempera ture every 5 minutes. RECORD data on Figure 1 and file it in the operating surveillance file.

10. IF the torus tenperature reaches 120*F during isolation conditions, depressurize the reactor to below 150 psig at nomal cooldown rates.

CAUTI0t1 VERIFY 2/3 core coverage before initiating containment cooling.

11. Commence torus cooling as necessary to maintain torus water temperature less than 170*F. .

12.  ?!otify the Shift Supervisor of systems started manually.

CAUTI0tl Detemine the radiological condition of the drywell and reactor coolant before resetting an isolation.

( 13. PLACE all air operated valves associated with an isolation in the CLOSED position prior to resetting an isolation.  ;

Failure to do this may cause the valve to open autcmatically  !

when the isolation is reset.

14. IF the Relief Valves are actuated and torus tenperature reaches 160*F or greater while the reactor pressure is above 150 psig, an external visual exam of the torus nust be conducted before resuning power operation.

E. DISCUSSION i

This procedure assuces the failure of a Feedwa ter Regulating Valve, a Reactor Feed Pump or the Feedwater Control System. 1 The failures are covered under the IMffEDIATE actions in order l of rore probable to least probable (i.e., feedwater valve pro-blems versus LPCI initiation). Time for action is presuced to exist between the first indication or alara and any Low Level Trips. )

I The IMMEDIATE actions are to restore level. If at any tine during the transient, +2 psig drywell pressure is reached, the loss of Coolant (Break Inside Drywell) (CGA-1) should be followed. Once a reactor scram occurs on Law level, the procedural steps in this procedure are censistent with the actions for Loss of Coolant (Break Outside Drywell) (DGA-3).

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. - DGA 5 Revision 4

. The loss of all feedwater will result in a low water level scram in about 7 seconds when operating at full power. On a reactor scran, an automatic setdown of reactor water level'setpoint to one-half of its original value (approximately 15 inches) takes place. An alarn, F.W. LEVEL SETPOINT AUTO-RUNB ACX will actuate on Panel 902(3)-5.

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