ML20040A970

Emergency Operating Procedure EP OP-23,Revision 1, Natural Circulation of Reactor Coolant. Related Correspondence

ML20040A970
Person / Time
Site:	Diablo Canyon
Issue date:	08/25/1980
From:	PACIFIC GAS & ELECTRIC CO.
To:
Shared Package
ML20040A967	List: ML20040A966 ML20040A968 ML20040A969 ML20040A970 ML20040A971 ML20040A972 ML20040A973 ML20040A974 ML20040A975
References
EP-OP-23, NUDOCS 8201230019
Download: ML20040A970 (4)

Text

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< riuMBER EP OP-23 Pacific Gas ami Electric Company REV!slON 3:D G r:EtE DATE l

8/25/20 O DEPARTMENT OF NUCLEAR PLANT OPERATIONS PAGE 1 OF 4 O! ABLO CANYON POWER PLANT UNIT NO(S) 1 CD 2 U@""9 g

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EMERGENCY OPERATIllG FROCEDURE NATURAL CIPCULATTON OF ppcTno cent ant d , TITLE Ill .1 APPROVED _

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PLANT MAN AGER SCOPE _

If forced reactor coolant flow is terminated, (all 4 RCP's tripped) tiatural Circulation of the coolant will occur OP-23when a temperature provides guidance for thegradient operatorexists be the core and the steam generators.

when Natural Circulation is required.

OP-23 assumes that off-site power is available but that all reactor coolant (PCP) are unavailable to cool the core (e.g. loss of CCW to RCP's, l pressure, RCP's failure).

SYMPTOMS

1. RTD bypass line low flow alams.

2. Reactor Coolant low flow protection bistable monitor lights on.

3. Reactor coolant flow indication decreases to near zero in all loops.

4. RCP breaker lights and motor ameters indicate breakers tripped.

Possibly RCP bus undervoltage or underfrequency.-  %

5. &/

'b AUTOMATIC ACTIONS _

Reactor trip if above P-7.

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1. JAN 15 ;gg , ;4 3

2. Turbine trip if above P-7. 0//c. ernet Steaa Dump Valve Operation. 6 bfk d

3. @

e y OSJECTIVES 1.

Recove decay heat frcm the Reactr Coolant Systea (RCS) and m state.

2. Maintain. the Reactor subtritical. '

8201250019 820114 E

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' ' NUMBER EP OP-23 DIABLO CANYON POWER PLANT UNIT NO(S) 1 AND 2 REvlsion 1 ,

TITLE NATUPAL CIRCULATION OF REACTOR COOLANT E2OF IMMEDIATE OPERATOR ACTIONS ACTIONS COMMENTS

1. Verify Reactor Trip or trip manually 1. Observe zero or negative rtartup if below P-7. rate, zero or decreasing flux levels and all rods in. Emergency

' - Borate 100 ppm for each stuck rod.

2. Verify Turbine Trip or trip manually 2. Observe stop valves closed, speed if below P-7. . decreasing and PCB's 532 and 632 open within 30 seconds.

3. Verify Steam Dump System operating. 3. Steam header pressure should be stable at approx.1000 psig. If required use the 10% atmosphere dump valves. .

4. Verify Auxiliary Feedwater to all available Steam Generators. 4. Manually start pumps if required.

SUBSEQUENT ACTIONS

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ACTIONS COMMENTS I

1. Monitor Steam Generator water levels.

a. Verify feedwater isolation at to T avg-

b. Verify auxiliary feedwater LCV's b. LCV 110,111,113 and 115 in AUf0 operating to maintain steam with toggle switches closed. ~

. generator levels in the narrow .i range.

2. Teminate any Reactor Coolant System dilution operations which may be in progress.

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3. Establish "CS conditions to enhance -

l Natur al Circulation.

a. Pressurizer pressure between 2200 a. Heater control in MANUAL. If and 2300 psig. necessary, use Aux. Spray (valve l

8145 or valve 8148) to depressurize

b. Pressurizer level above 22%.

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NUEER EP OP-23 fw----- R E V!110N l DI ABLO CANYON PCWER PLANT UNIT NO(S) 1 AND 2 DATE 8/25/80 TITLE I4ATURAL CIRCULATION OF REACTOR COOLANT PAGE 3OF 4 '

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COMMENTS ACTIONS

4. Assures 50*F subcooling at 2200 l

4. Verify core outlet temperature 'psig RCS pressure. Reduce HC507 :

(thermocouple average) is less than or eoual to 600 F. Increase (steam header pressure) setpoint {

or use t.unual valve control to  ;

steam oumo flow as necessary to increase steam flow.

Jimit core outlet temoerature. I

5. C4UTION_: Trends in parameter

5. The effectiveness of Natural Circulation values are most significant in is verified by: verifying Natural Circulation. ,

Absolute values may vary. I Core exit temperature is at least a. P-250 averages T/C data address:  !

a. U0091. May also take short form 50 F cooler than pressurizer temperature and exhibits stable or T/C core map every 10 min.

decreasing values.

Cold leg temperatures in all active b. Cold leg temps in TP.dl3,423,433

b. S/G pressure will loops are approximately eoual to and 443.

determine sat. temp.

S/G saturation temperature.

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Hot leg temperatures in all active c. High AT (>64 F) tends to inhibit

c. natural circulation 1 cops are showing a stable or decreasing trend. Hot to cold leg ,

AT should be less than 64 F.  !

d. All available Steam Generators steamino and steam header pressure  !

stabl e. L. ,

If the core exit T/C average readino 6, Open steam duma valves slowly 1 6.

increases for 3 consecutive measurement and allow time for the tempera- ll intervals, reduce steam header pressure ture to stabilize.  !

to obtain greater natural circulation flows.

Verify shutdcwn marcin is maintained 7. NOTE: If uncontrolled cooldown

7. is anticipated, inject during all phases of natural circulation, contents of Baron Injection Tank immedia tely, Monitor NIS channels to verify the a. Reset source range detectors when

a. below P-6 setpoint.

reactor receins subcritical,

b. Perfom shutdown margin calculations for anticipated final RCS conditions.- .

Boric Acid HC110, Primary Water

- c. Verify RMCS flows to blender are set c. HClli.

to provide the proper baron concentra-tion. -

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. . rautaaER EP OP-23 . f-D!.:.BLO CANYON POWER PLANT UNIT NO(S) 1 Ai10 2 REvistora 1 DATE 8/25/80 TITLE f!ATURAL CIRCULATICN OF REACTOR COOLA?iT PAGE 40F

• APPEtIDIX Z  !

i EtERGEfiCY PROCEDURE tiOTIFICAT10ti IrlSTRUCTIONS f I

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1. When this emergency procedure has been activated and upon direction from the Shift Foreman' proceed as follows: '.

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a. flotify the Plant Superintendent.and Supervisor of Operations or their !

designated alternates.

I flotify those i

b. Designate this event a riotification of Unusual Event. '

agencies given in General Appendix 2 of the Emergency Procedures I (flotification of Outside Agencies in the Event of an Emergency).

c. Within one hour notify the flRC Operations Center using the red phone in the Control Room. Gather sufficient information fromflotify all sources the prior to calling so that the phone call is meaningful.

tiRC that your call is pursuant to 10CFR Part 50.72, (flotification of Significant Events).

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