ML17192A673

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Emergency Procedure DGA-3,Revision 4, Loss of Coolant (Break Outside Drywall)
ML17192A673
Person / Time
Site: Dresden Constellation icon.png
Issue date: 01/12/1980
From:
COMMONWEALTH EDISON CO.
To:
Shared Package
ML17192A611 List:
References
DGA-3, NUDOCS 8005080496
Download: ML17192A673 (9)
v • d • e


Text

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A.

SYMPTOMS LOS_S OF COOLANT (BREAK OUTSIDE DRYWELL)

1.

902(3)-3 Alarms

a.

MAIN STEAM LINE HIGH RADIATION

b.

RX BLDG VENT CH~EL A(B) HI RADIATION

  • ,i_..
c.

HPCI COND STORAGE TANK 2/3 LOW LEVEL

d.

TORUS LEVEL HI/LOW

e.

ISOLATION CONDENSER-VENT HI RADIATION

f.

RX BLDG.CH A OR CH.B HIGH RADIATION

g.

ISOLATION CONDENSER HIGH TEMP

h.

TURBINE BLDG HI RADIATION

i.

ISOLATION CONDENSER LEVEL HI/LO

j.

AREA HIGH TEMP

k.

REACTOR LOW WATER LEVEL

1.

ISOLATION CONDENSER LINE BREAK

m.

REACTOR VESSEL LOW PRESSURE

2.

903(3)-4 Alarms 80 o&osotrr~

DGA-3 Revision 4 January 12, 1980

a.

RX BLDG FLOOR DRAIN SUMP A(B) HIGH LEVEL

b.

TURBINE BLDG EQUI.P DRAIN SUMP HIGH LEVEL

d.

RX BLDG EQUIP DRAIN TANK HIGH LEVEL

e.

RX BLDG EQUIP DRAIN.TANK HIGH TEMP

f.

VALVE LEAK DETECTOR SYS HIGH TEMP

3.

903(3)-5 Alarms

'I

a.

CHANNEL A(B).MAIN STM LINE LOW PRESS

b.

CHANNEL A/B CONDENSER LOW VACUUM 1 of 9 APPROVED

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12'80 0.0.S.R~

,...---,--~

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c.

CHANNEL A(B) MAr'N STM ISOL. HI RADIATION

d.

CHANNEL A(B) REACTOR LO LO LEVEL

e.

CHANNEL A/B REACTOR LOW LEVEL

f.

CHANNEL A/B MAIN'STM LINE HI RADIATION

g.

MAIN STEAM LINE LEAKAGE

h.

CHANNEL A(B) MAIN STM LINE HIGH FLOW DGA-3 Revision 4

i.

CHANNEL A(B) REACTOR VESSEL HI WATER LEVEL

j.

CHANNEL A(B) MAIN STM TFNNEL HIGH TEMP

k.

CHANNEL A(B) REACTOR SCRAM

1.

REACTOR VESSEL HIGH LEVEL

m.

CONDENSER LOW VACUUM

n.

REACTOR VESSEL LOW LEVEL

4.

902(3)-6 Alarms

a.

HEATER HIGH LEVEL'

b.

MST SEP DRAIN TANK HIGH LEVEL

c.

HEATER FLASH TANK HIGH LEVEL

d.

COND BOOSTER PUMP SUCTION LOW PRESS

e.

CONDENSATE PUMP DiSCH LOW PRESS

f.

RFP SUCTION LOW PRESSURE

g.

CONDENSER LOW LEVEL

5.

902(3)-7 Alarms AIR EJECTOR 2A(2B) STM LOW PRESS B.

AUTOMATIC ACTION

a.

Reactor Scram

  • 2 of 9 APPROVED JAN 12'80 D.O.S.R.

_,,,..... ~--

r'

    • e DGA.'..3 Revision 4
b.

Turb.ine Trip

c.

Group I, -II and III Isolations

d.

RFP Trip

e.

HPCI Initi~tion

f.

LPCI and Core Spray Iriitiation

g.

Rx Bldg Vent Fans Trip

h.

SBGT System Start

i.

Emergency DG 2(3) and 2/3 Start

j.

Isolation Condenser Isolation

k.

HPCI System Isolation:.

C.

IMMEDIATE ACTIONS

1.

'CAllTION A steam env~ronment may damage safety-related equ~pment, cause erratic indi-cations or result in inadvertent trips or initiatiqns.

Such results must be evaluated for safety significance.

DO NOT dispatch personnel to an area of a suspected pipe break without consideration of adverse environments.

CAllTION Any AllTO ACTIONS which should initiate I

must.be verified, preferably by at least two independent indications. Verifica-tion means that if the AllTO ACTION does not occur, the action should be accomplished manually.

DO NOT manually initiate a system unless the AllTO function.has failed.

DO NOT block or* defeat a system logic unless adequate core cooling is assured.*

Maintain feedwater flow to the reactor.

MONITOR reactor water level using mul t;~ple level indications.

3 of 9

...__....,.....---~---. -.,

  • w a:

.... ¥-.w:----*

APPROVED JAN 12'80 D.O.S.R.

\\..

CAUTION IF there is a failure to completely isolate a suspected break on either automatic or manual signal, then MANUALLY SCRAM the reactor.

DGA-3 Revision 4

2.

VERIFY Automatic Isolation of appropriate or affected systems.

3.

IF a reactor scram occurs, follow the Scram procedure (DGP 2-3).

CAUTION IF opened manually for pressure control, Pressure Relief Valves should be rotated to distribute heat uniformly to the torus.

4.

IF a Group I Isolation occurs, MONITOR reactor pressure by multiple indications.

Control reactor pressure with Iso-lation Condenser, if ~vailable, or Pressure Relief Valves.

5.

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

6.

IF high pressure systems fail to initiate or cannot maintain

level,
a.

START Core Spray or LPCI Pumps and NOTE If no ECCS is available a Condensate Pump may be used, provided the pump is capable of adding water to the vessel.

CAPTION Do NOT nanually OPEN Pressure Relief Valves until it is verified that at least one Core Spray, LPCI or Conden-sate Pump is running.

b.

MANLTALLY initiate Auto Blowdown 120 seconds after level reaches -59".

4 of 9 APP?0\\1ED JAN 12~80 o.o.s.R.

I I

r.

CAUTION DGA-3 Revision 4 IF Yarway r~f erence leg flashing occurs during depr~ssurization, Yarway indication may be above -59" such that LPCI and Core Spray Injection Valves do not open automatically.

7.

VERIFY that LPCI or Core Spray injection occurs when reactor pressure decreases to~350 psig as indicated by more.than one indication.

8.

EVACUATE the affected :,area.

D.

SUBSEQUENT.ACTIONS I

1.

Station an additional op'erator to monitor 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 followin~ conditions occur:

3.
a.

Reactor water lev;el indications are co.nt inuing to decrease with ECGS operating.

b.

Reactor water le~~l is sustained at a level below the top of the ac'tive fuel as indicated by available level indications'.

c.

Reactor water level indication is unavailable.

d.

Less than design ~low is indicated on Feedwater or ECC Systems when 1design flow is requiren.

IF desired and IF level approaches the high level trip set-points for Feedwater a'nd/or HPCI, take manual confrol of these systems to maintain level and to prevent trips of Feedwater and HPCI Systems.

4.

VERIFY SBGT System STARTS.

5.

IF the break has been successfully isolated and reactor opera-tion is unaffected, continue normal operation per the appli-1

'6.

cable Technical Specifications.

IF the Main Condenser is available and plant shutdown is necessary, follow the procedure for Normal Shutdown from Power (DGP 2-1).

5 of 9 APPROVED JAN 12'80 D.O.S.R.

l

7.

DGA-3 Revision 4 IF the Main Condenser is not available and shutdown is necessary, cooldown us~ng the Isolation Condenser.

8.

IF Relief Valves have been actuated, continually MONITOR and RECORD torus water* temperature every 5 minutes.

RECORD data on Figure 1 and file it.in the operating surveillance file.

9.

IF the torus temperature reaches 120°F during isolation conditions, DEPRESSURIZE the reactor to below 150 psig at normal cooldown rates.

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

10.

Commence torus cooling as necessary to maintain torus water temperature less than l70°F.

11.

Notify the Shift Supervisor of systems started manually.

12.

Carry out High Radiation procedure DGA-13" CAUTION Determine 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 tQ resetting an isolation.. Failure to do this may cause the valve to open automatically when the isolation is reset.

14.

IF the Relief Valves are actuated and torus te~perature reaches 160°F or greater while the reactor pressure is above 150 psig, an external visual exam of the torus must be conducted before resuming power operation.

E.

DISCUSSION This procedure has been written assuming a leak outside the drywell large enough to initiate automatic isolations or automatic responses by plant systems.

With a primary containment isolation signal present, the determining parameter is drywell pressure.

If drywell pressure 6 of 9 APPRnVED JAN 12'80 o.u.s.R.

.-----.....-------,-,..--*------ ~-

DGA-3 Revision 4 has reached +2 psig, then Loss of Coolant (Break Inside Drywell) (DGA-1) should be followed.

If drywell pressure has not reached +2 psig, then this procedure should be followed.

It must be understood that the reactor

.may or may not scram and may or may not isolate. If the transient is sufficently small and does not involve reactor safety considera-tions, then the operator should refer to Loss of Coolant (Slow Leak)

(DGA-2).

The goal of IMMEDIATE operator actions is to reduce the loss of primary inventory as quickly as possible.

This goal is accomplished by verifying makeup water is available to the reactor and by ensu~ing the suspected break is i~olated.

On any automatic initiation of a safety function, the operator is to assume a true initiating event has occurred, until otherwise confirmed by two or more independent process* indications.

IMMEDIATE operator actions include verification, of automatic actions and taking manual action to initiate an automatic function.. whenever an automatic action did not occur that should have occurred.

Automatic controls should not be placed in Manual mode, unless 1) misoperation in Automatic mode is confirmed :by at least two independent process parameter indications; or 2) core cooling is assured.

If any system is switched from AutolMtic to Manual mode, then frequent checks of the controlled par*ameter must be made.

The indicated water level, where provided by YARWAY instrumen-tation utilizing reference legs in the drywell, is dependent upon drywell temperature.

Very large increases in drywell temperature (an increase from 135°F to 340°F) could result in a level inaccuracy (as mu~h as 14 inches) with indicated level being higher than actual level.

During rapid reactor depressurization (with Auto Blowdown for example), and par-ticularly below 500 psig, th¢ operator should utilize GEMAC level indicators to give bac.~up information on vessel water level.

The operator should not turn off any ECCS unless there is sufficient confirming information from GEMAC level instruments that vessel water level has been restored.

The operator should not rely on the Yarways if erratic behavior, indicative of ref-erence leg flashing, has occurred until the Yarway readings are on scale and in reasonable agreement with GEMAC instruments.

The goal of.SUBSEQUENT operator actions is to bring the plant to a stable condition, where the vessel water level is steady or cycling within a satisfactory range, and containment cooling has been established.

Other objectives of SUBSEQUENT actions is to limit the release of off-site radiation by maintaining the integrity 7 of 9 APPRnVEO

,~N 12'80 D.O.S.R.

~.

e*:*

DGA-3 Revision 4

  • l of the primary and secondary;, containments, and to keep the bulk temperature below 170°F to prevent excessive loads to the pool boundary and structures duririg safety/relief valve discharges.

No emergency core cooling system should be shutoff unless there are multiple confirmiqg process parameter indications that the co.re and containment are in-a safe, stable condition.

- When manual operation of systems placed in manual is no. longer needed, restore the system t'o Automatic/Standby mode, if possible.

Any emergency core cooling s'ystem should not be shut off unless there are multiple confirmiqg process indications that the core and ~ontainment are in a saf~, st~ble condition.

8.of 9 APPR0\\/ED JAN 12'80 o.o.s.R.

APPRnVtO e

  • e DGA-3 JAN 12'80-Revision 4 D.O.S.R.

FIGURE 1 Torus Temperature and T'ime Tempera tu re was taken Time Temp.

Time Temp.

I

  • Time Temp.

Time Temp.

i I

I 9 of 9 (FINAL)

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