ML13322A858

Plant Hot Shutdown to Cold Conditions, Revision 14

ML13322A858
Person / Time
Site:	San Onofre
Issue date:	05/13/1980
From:	Brunet R, Curran J Southern California Edison Co
To:
Shared Package
ML13322A854	List: ML13322A853 ML13322A855 ML13322A857 ML13322A858 ML13322A860 ML13322A863 ML13322A873 ML13322A892
References
S-3-1.5, NUDOCS 8008060310
Download: ML13322A858 (8)

Text

SAN ONOFRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION 5-3-1.5 Revision 14 MAY 13 58O.

PLANT HOT SHUTDOWN TO COLD CONDITIONS

1.

OBJECTIVE This instruction describes a safe and efficient method of cooling down and depressurizing the reactor cycle from the hot shutdown to a cold or refueling.condition in which the reactor coolant temperature is maintained less than 150*F.

II.

CONDITIONSS A. The plant is in the hot shutdown condition. One shutdown group shall be wi thdrawn to the "cocked" position except for the conditions listed under "Precautions," Item III-A.

B. Primary Makeup Water and Boric Acid Systems have sufficient storage to comnpensate for reactor coolant shrinkage.

Ill.

PRECAUTIONS A. One shutdown group of control rods must be 320 steDs withdrawn whenever positive reactivity is being inserted by boron dilution, xenon decay or cooldown.

The following two exceptions to this rule may oe applied:

1. The Reactor Coolant System has been borated to at least the hot, xenon free, boron concentration and is being maintained at hot shutdown conditions.

2. The Reactor.Coolant System has been borated to the cold shutdown boron concentration and the primary plant is being cooled down.

B. The pressurizer spray valves shall be operated as necessary to main tain the pressurizer boron concentration within +150 ppm to -50 ppm of the main coolant boron concentration to minimize the amount of reactivity tied up in this manner..

C. The cooldovn. rate of the Reactor Coolant System shall not exceed 1000F/hr.

NOTE: The maximum allowable cooldown rate is subject to change during plant life as the observed or expected shift in design transition temperature (DTT) increases (refer to heatup and cooldown curve).

D. To limit the consequences of a steam line break establish 4% AK/K shutdown, hot, xenon free, all rods in, prior to removing the safety Injection system from service.

T1.L C

SAN ONOFiRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION S-3-1.5 Revisjnn ae-MAY 1 3 102 E. -Component cooling to the reactor coolant pumps must be supplied any time a reactor coolant pump is operating and must not be terminated to an idle pump until the reactor cycle has been cooled to the cold condition (< 200 0F).

F. Do not maintain the pressurizer level above 80% unless required for system cooldown or startup operations.

G. The containment spray system, the refueling water storage tank, the associated valves and interlocks shall remain operable per Tech. Spec.

3.3 while above 200*F in the reactor coolant system.

H. During the solid water phase of cooldown, reactor coolant pumps must be run continuously. Should abnormal or unusual conditions cause securing of all reactor coolant pumps, restart is permitted only after evaluating RCS temperature gradients.

In addition, at the completion of cooldown the reactor coolant pump shall be run sufficient additional time to insure that all reactor coolant systems and steam generator metal temperatures have equalized with reactor coolant liquid temperatures.

I. Tests or maintenance activities that might affect reactor coolant system pressure shall not be performed during solid system operation.

IV. CHECK-OFF LIST See PSSO-119 V.

INSTRUCTIONS Important Steps Key Points

1.

If the Reactor Coolant System is to be opened for repair or refueling, initiate degassing of the reactor coolant in accordance with Instruction S-3-1.12, Reactor Dissolved Gas Concentration Control.

2. Borate the Reactor Coolant System

2. a. The reactor coolant to the cold shutdown concentration system must be borated in accordance with Operating to the cold shutdown Instructions S-3-2.5 and S-3-1.3..

concentration and verified by sample analysis before a controlled cooldown is initiated.

SAN ONOFRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION S-3-1.5 Revision 14 MAY 1 3 1M Page 3 Important Steps Key Points NOTE:. The reactor shutdown will

b. A minimum of one normally be 3% with all rods reactor coolant pump Inserted.

When the reactor must be in operation coolant system is to be during any boron concen opened, a shutdown margin tration change.

Pump

> 5% will be maintained and A or B must be used for 7 10% with the reactor head spray flow for equal Temoved.

izing boron concentra tions.

NOTE: If a Chemical Technician is

c.

During this operation, not on duty, operators will the pressurizer liquid establish a main coolant level is allowed to sample line flush for 15 increase above the no minutes and then draw a sample load programmed level.

properly.labeled for analysis Place FCV-1112 on manual as soon as Chemical Technician and set the flow for arrives on site.

approximately 110 gpm until the boron additior is complete or the pressurizer level indi cation is near the upper limit. If possible, do not allow letdown diversion to radwaste or volume control system

3. Prepare additional batches of boric to makeup.

acid to refill the boric acid storage tank.

4. Set the reactor coolant makeup control

4. a. Verify that a normal level for automatic makeup at the refueling in the volume control tank or cold shutdown boron concentration, is maintained during the whichever is applicable.

cooldown.

b. Verify proper boron concentration at blend device outlet.

5. Periodically sample the reactor coolant 5. a. Confirm that the intended and pressurizer liquid.

boron concentration change is accomplished.

b. Check the reduction in coolant activity.

c. Check the dissolved hydrogen concentration.

SAN ON0FRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION S-3-1.5 Revision 14 -

MAY 1 3 50 Page 4 Important Steps Key Points

6. Switch off all pressurizer heaters.

6. a. Use reading sheet included Pressurizer liquid and RCS liquid in check-off sheet form temperature and pressure readings will PSSO 119.

be taken every 30 minutes until cold shutdown condition is reached, unless recorder TR-430, Pr ssurizer Temperature is in service.

7. Begin cooldown of the Reactor

7. a. Slowly adjust the steam Coolant System. Place steam dump control to increase dump controller 418A on manual the dumping rate.

control and if possible maintain steam dump to condenser only.

b. Do not exceed a cooldown rate as shown on the pres sure tumperature curve.

Caution:

If cooldown exceeds 50F/hr contraction of the reactor coolant may exceed the automatic makeup capacity.

8. Begin cooldown of the pressurizer

8. a. Transfer spray valves and depressurization of the Pressurizer PC-430C and PC-430H to and Reactor Coolant System.

manual control.

b. Slowly open a spray valve and maintain the reactor coolant pressure within the limits shown on the pressure-temperature curve.

c. The spray flow must be controlled to limit the rate of pressurizer cooldown to 195*F/hr.

d. The temperature differen:

between the pressurizer and reactor coolant shoul not exceed a maximum of 200*F between TI-430C and TI-430B, or TR-402 depending on which reactc coolant pump is operating

SAN ONOFRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION S-3-1.5 Revision 14 -

MAY 1 3 1980 Page 5 Important Steps Key Points

9. Stop all reactor coolant pumps

9. a. Pump B must be operated except B to reduce heating of for spray flow. If Pump the Reactor Coolant System.

B is not available, pumps A and C will be used.

10. Add additional boric acid as

10. a. Sample the pressurizer required if refueling concentra-liquid and reactor coolar tion is to be achieved.

for boron concentration.

11.

Manually block the safety injection actuation circuit when the alert to block safety injection alarm is received or when pressure is approximately 1750 psig.

(See Precaution D)

12. As cooldown progresses, maintain

12. a. Promotes better cooling the pressurizer liquid as high of the metal in the upper as possible.

steam space.

b. Do not collapse the bubble at this time.

Maintain approximately 90% level.

13. As the letdown flow decreases, open

13. Letdown flow may be varied additional letdown orifices to as required by system maintain desired letdown flow.

operating conditions.

14. Open reactor coolant pump seal bypass flow Valve CV-276 when any one of the three seal leak-off flows is (1) gpm on a running pump and the pres sure is 1500 psig.

15. Continue to cooldown by periodically resetting the steam dump control.

16. At 500 psig, establish two positive

16. a. Refer to 0.1. S-3-2.21.

barriers between the feedwater and reactor coolant system.

17. When system pressure decreases to 400 psi, arm the OMS by operating CS-3A and CS-6 to the enable position.

18. When the reactor coolant pressure decreases to 400 psig, start preliminary alignment of the Residual Heat Removal Sstem. See Operating Instruction

rSAN ONOFRE NUCLEAR GENE& ING STATION OPERALLG INSTRUCTION P-3-1.5 R~V1I~f 14 lGPage 6

Rpyosion 14 -

NuM Important Steps Key Point

19.

Break vacuum from thy condenser

.19. a. Open the condenser vacuum when no longer needed.

breaker.

b. Stop the condenser vacuum pumps and/or secure steam to the air ejectors.

c. Stop both gland seal condenser exhauster blowers.

d. When the condenser is at atmospheric pressure, shut off the steam to the Turbine Gland Seal System.

20.

Place the residual heat removal loop in service in accordance with Operating Instruction S-3-2.12.

21.

When the residual heat removal

21.

a. Place FC-1112 on manual loop is in service, increase the and increase the charging pressurizer level and collapse flow. Do not allow pressure the bubble as indicated by LI-435.

to exceed 400 psig.

22.

The reactor coolant system is filled

22.

and solid, therefore;

a. Assign a reactor operator to monitor

a. Operator monitoring is not required the RCS pressure.

when the OMS is operational.

b. Do not close MOV813 and 814, residual

b. To provide relief paths to RV20b heat removal inlets or LCV1112, CV202, and normal letdown by PCV1lO5.

203 and 204, normal letdown, except as required for RCS hydrostatic tests.

f23.

Continue to operate reactor coolant

23. Do oot reduce pressure pump "B" during the cooldown to below RC pump NPSH requireqr obtain a uniform cooldown rate ofe Oents.

all coolant loops and provide spray requirements to cool the pressurizer.

24.

When the main steam pressure reaches approximately atmospheric, apply a nitrogen blanket to the main steam lines and close the trap free blow valves as required.

25.

Raise the water level in the steam.

25*

As steam generator levels generators to approximately 120% of increase, measure rate of indicated level.

change to calculate time to reach 120% level.

SAN ONOFRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION S-3-1.5 Revision 14 -

Ay 1 g

Page 7 Important Steps Key Points

26.

Stop the last reactor coolant pump

26. a. Open ai arpya when the final cold shutdown CV-30 4 closc a in temperature is reached. Hang caution CV-30 and s

v tags on the RCP control switches indicating the RCS temperature at the time the last pump was stopped.

b Au t c har line flcontrollte esred-11 ol Restart of the RCP's will only be conn te deire cool affected after determining that RV-206 is available as a relief flow path and carefully assessing ci l

RCS temperature gradients or the auxiliary spray line evaluating the potential for having until the pressurizer developed temperature gradients.

temperature is approximately 1500F, indicated by TI-430A.

27.

The Reactor Coolant System may be maintained at pressure as follows:

a. Manually adjust FC-1112 to obtain a set charging flow.

b. Control the pressure automatically with the letdown system pressure controller PC-11050.

28.

When the desired shutdown temperature 28.8. Residual heat removal is achieved and the reactor coolant pump.

pumps have been taken out of service, some auxiliary coolant system com-

b. Component cooling pumip.

ponents may be taken out of service dependent upon Cooling System heat

c. Residual heat exchanger.

load.

d. Component cooling heat exchanger.

SAN ONOFRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION S-3-1.5 Revision 14 Pag 8 MAY 1 3 1980 VI.

FINAL CONDITIONS The unit is in the cold shutdown condition.

R. R. BRUNET SUPERINTENDENT, UNIT 1 APPROVED:

J. M. CURRAN PLANT MANAGER AJS/yc