ML20066C818

Rev a to IOP-7,Cooldown to Cold Shutdown,Main Condenser Not Available

ML20066C818
Person / Time
Site:	05000605
Issue date:	01/09/1991
From:	Torres W GENERAL ELECTRIC CO.
To:
Shared Package
ML20066C783	List: ML20066C781 ML20066C799 ML20066C803 ML20066C806 ML20066C809 ML20066C811 ML20066C813 ML20066C815 ML20066C817 ML20066C818 ML20066C820 ML20066C823 ML20066C826
References
23A6169AG, 23A6169AG-RA, NUDOCS 9101110240
Download: ML20066C818 (10)

Text

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REv A REVISION STATUS SHEET DOCUMENT TITLE LOP-7, COOLDOWN TO COLD SHUTDOWN. MAIN CONDENSER NOT AVAILABLE TYPE: OPERATINL PROCEDURE LEGEND OR DESCRIPTION OF GROUPS FMF: K6/7  !

MPL ITEM NO: ABc3020 REVISIONS -l l

A PRELIMINARY ISSUE PER gas ERM - DMH-3234 765 4

' PRINTS TO MADE BY APPROVALS DEPT -: LOCATION W B TORRES C K TANG - GE NUCLEAR ENERGY SANJOSE-CHKD BY - ISSUED F E WILHEMI O A BAYUS 9101110240 910109 PDR ADOCK 05000605 A PDR

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@) GE Nuclear Energy 23A6160AG SH No 2 REV A TABLE OF CONTENTS RaQA

1. SCOPE / APPLICABILITY 3

2. DISCUSSION ,3 ,

3. PRECAUTIONS AND LIMITATIONS 3

4. PREREQUISITES 5

5. PROCEDURE 5-5.1 Preparation for Cooldown 6-5.2 Maln Steam System Isolation and Reactor Depressurization - 7-5,3 Shutdown Cooling 7-5.4 - Reactor Pressure Decreases to Atmospheric 8 5.5 Maintaining Cold Shutdown 9

6. REFERENCES 10 4

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O GE Nuclear Energy 23A6169AG SH NO.- 3 REV A 1.0 SCOPE / APPLICABILITY.

This procedure provides the detailed instructions for performing and sequencing the various steps required to achieve and maintain cold shutdown conditions when the mein condenser is not available, utilizing the Reactor Saf aty Relief Valves ano *.i e RHH Shutdown Cooling Mode for depressurization and cooldown.

2.0 DISCUSSION This procedure provides the means for organizing the diverse activities associated with conducting a unit cooldown to a cold shutdown condition with the main condenser not available. The cooldown process consists of depressurization using primarily the Reactor Safety Relief Valves, controlling suppression pool temperature using the RHR Suppression Pool Coollng Mode, and cooldown of the reactor using the RHR Shutdown Cooling Mode.

Cold Shutdown condition is defined as follows:' Reactor Mode Switch in the SHUTDOWN position, and reactor coolant temperature s 93 'C.

The depressurization and cooldown actions may be conducted subsequent to the completion of LOP 5, " Unit Shutdown to Unit Off-Une, Main Condenser Available".

3.0 PRECAUTIONS AND LIMITATIONS' 3.1 - Do not exceed a cocidown rate of 55 'C per hour as averaged over any one hour period.

3.2 Limit the cooldown rate such that the rate of positive reactivity insertion added by cooldown does not exceed the capability of the control rods to insert negative reactMty to maintain the reactor -

subcritical.

3.3 Maintain reactor water level in the normal operating range of 425.5 cm to 448.5 cm on the Narrow Range water level Instruments through out the cooldown.'

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3.0 PRECAUTIONS AND LIMITATIONS (continued) 3.4 When reactor coolant temperature is maintained at less than 100 'C, maintain reactor water chemistry within the following limits:

Chlorides < 10 ppb -

Conductivity at 25 *C < .1.0 pS/cm pH at 25 'O 5.9 - 8.3 i Silica (SiO2) - < 100 ppb Sulfate < 10 ppb TotalIron (Fe) < 10.0 ppb total Copper (Cu) < 0.5 ppb All other metals. < . 4.5 ppb 3.5 Maintain Control Rod Drive' Hydraulic System cooling water-chemistry within the following limits:

Chlorides < ,10.0 ppb .

Conductivlty' at 25 'O < 0.25 pS/cm Silica (SiO2) < 20.0 ppb Sulfate .< .10.0 ppb '

pH 6.2 - 8.0 Total tron' < 10.0 ppb Total Copper (Cu) < 1.0 ppb All othat metals.-  : < - 4.0 ppb -

Organic Impurttles

.(Equivalent AK ( S/cm)) L< 0.2 a

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• Does not include an incremental conductivtty value of 0.8 pS/cm at 25 *C due to carbon dioxide from air in the water stored in tanks open to the atrnosphere.

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V GE Nuclear Energy 23A6169AG sH No. 5 ;

AEV A 4.0 PREREQUISITES 4.1 The reactor is shutdown, or suberitical and procu. ding to full shutdown and mode switch is in STARTUP/ HOT STANDBY position.

4.2 At least the following systems are available for reducing reactor pressure and to achieve the cooldown:

a. RHR System for operation in the Suppression Pool Cooling and Shutdown Cooling Modes.

b. Reactor Safety / Relief valves for depressurization.

c. Reactor Building Cooling Water System to provide cooling water to the RHR heat exchangers,

d. Suppression Pool water level at the normal range (later] and average temperature less than [later) to provide a heat sink for depressurization.

5.0 PROCEDURE

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• NO TE * *

• This procedure begins with the assumption that the plant is at normal operating temperature and pressure, reactor shutdown or currently in progress. As speciSc to the initial conditions of pressure and temperature, this procedure may be entered wherever appropriate. This procedure may be terminated whenever the desired conditions are achieved.

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0 GE Nuclear Energy 23A6169AG REV A SH NO 6 5.1 Preparation for Cooldown 5.1.1 Initiate the recording of cooldown trend of at least the following parameters:

Cooldown Rate Bottom Head Drain Temperature (later) -

- Coolant Temperatures (later) 5.1.2 Verify the appropriate CRT displays have been selected per SOP-(later), " Performance Monitoring System".

5.2 Main Steam System Isolation and Reactor depressurization 5.2.1 Start the RCIC System to provide high pressure makeup to the reactor vessel and to assist RPV depressurization.

5.2.2 Initiate two loops of the RHR system in the Suppression Pool Cooling mode per SOP E11. " Residual Heat Removal System".

5.2.3 Use the following sequence of Safety Relief valve opening to control reactor pressure: [ sequence later) 5.2.4 Shutdown the motor driven feedpump, per SOP-[later),- g

" Condensate and Feedwater System". Malntain MDRFP in i "40Standby"2,until kg/cm reactor pressure has decreased below 5.2.5 If main condenser vacuum is to be maintained, startup the Startup SJAEs and shutdown the main SJAEs per SOP-[later),

" Condenser Evacuation System", and shift the turbine gland sealing steam to the Auxiliary Boller.

5.2.6 Align the Feedwater and Condensate System in the Long Cycle or Short Cycle Cleanup mode per SOP-[later),

" Condensate and Feedwater System".

5.2.7 Close the inboard MSIVs (B21 F071s) one at a time by placing its control switch to TEST CLOSE position.

5.2.8 Close the main steam line drain line containment isolation valves (B21 F141 and F142).

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O GE Nuclear Energy 23A6169AG SH NO . 7 AEV A 5.2 Main Steam System isolation and Reactor copressurization (continuem 5.2.9 When steam pressure downstream of the MSIVs has decreased to

later), similarly close the outboard MSIVs (B21 F072s).

5.2.10 Continue to use the designated Safety Relief valves to depressurize the reactor and maintain the specified cooldown rate UNTIL reactor pressure has decreased to a pressure where the shutdown cooling interlock has cleared. Placo remaining loop of RHR C/ stem in the Suppression Cooling mode if necessary to control suppression pool temperature.

5.3 Shutdown Cooling 5.3.1 Warm one loop of RHR for shutdown cooling operation per SOP-E11, " Residual Heat Removal System". Durino warming of the RHR, control and maintain RPV pressure with RCIC to below the shutdown cooling interlock pressure.

5.3.2 When warming is complete, initiate one loop of the RHR System in the Shutdown Cooling mode per SOP E11,

" Residual Heat Removal System".

r CAUTION

• Do not permit shutdown cooling flow to decrease below the setpoint for the RHR pump minimum flow valve setpoint of [lator).

• Do not allow reactor water level to decrease below L3 as this will isolate the Shutdown Cooling mode of the RHR System.

A 5.3.3 Malntain at least [ number, later) recirculation pumps in operation running at [ speed, later). If no recirculation pumps, ,

or less than [ number,later) recirculation pumps are running at I

[ speed, later), raise the RPV water level to [later) to promote l

core flow (natural circulation). '

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O GE Nuclear Energy 23A6169AG SH NO . S REV A 5.3 Shutdown Cooling (continued) 5.3.4 Throttle RHR heat exchanger service water as necessary to maintain the specified cooldown rate, averaged over any one-hour period.

5.3.5 Secure the RHR loop (s) that are operating in the Suppression Pool Cooling mode when pool temperatures are normal.

5.3.6 initiate reactor head spray, if desired, in accordance with SOP-G31," Reactor Water Cleanup System" Section 4.3.

5.3.7 Warm and place additionalloop(s) of RHR System into the Shutdown Cooling mode as necessary for cooldown.

5.4 Reactor Pressure Decreases to Atmospheric 5.4.1 Shutdown the RCIC System prior to reachint when no longer needed for reactor wuter control,lev per{3.5 kg/cm2)

SOP E51," Reactor Core Isolation Cor,;ifig Spiem".

CAUTION Do not reduce reactor pressure vessel temperature below 21 *C [TE later) unless the head bolts are detensioned.

5.4.2 At 0 kg/cm2 and a reactor temperature of [87 'C, TE late'r),

open reactor head vent valves B21 F012 and F013, and close the head vent to main steamline valve F014.

5.4.3 Set the setpoint of the Pressure Regulator to [10 kg/cm2),

5.4.4 Place the reactor mode switch in the SHUTDOWN position.

5.4.5 Reset the RPS scram logic, i

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GE Nuclear Energy REV A 5.5 Maintaining Cold Shutdown l l 5.5.1 Mcintain reactor vessel water level on the Shutdown Range ,

instrumentation within the range of [later). When it is i necessary to reject water to Radwaste with CUW, maintain CUW filter demineralizer inlet temperature less than [54*C).

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• NO TE * * *  ;

1 During periods oflow flow through the core M water temperature in the upper part at the core cou

• be at or above saluration while the the reactor bottom head drain temperature is wellbelow saturation.

5.5.2 Maintain one loop of the RHR System operating in thu -

Shutdown Cooling Mode per SOP-E11 Adjust the RHR heat exchanger cooling water flow rate or bypass valve as necessary to maintain the reactor vessel flange and head flange temperature [ TE's later) greater than or equal to 21 'C and the reactor coolant temperature [ TE later ) less than or equal to 87 -

'C.

5.5.3 Check for thermal stratification by monitoring reactor water -

temperature [ TE-later ] and [ later ] . Verify that they are within (later 'C) of each other.

5.5.4 Initiate reactor head spray, as required, per SOP-G31, to maintain the temperature difference between the bottom head drain and [ later] to within [ later 'O ) of each other.

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6.0 REFERENCES

O.1 General Electric Service Information Letter SIL-357," Control of Renctor Vessel Temperatute/ Pressure During Shutdown".

6.2 General Electric Service Information Letter SIL-388,"RHR Valve Misalignment During Shutdown Cooling Operation".

6.3 U.S. NRC lE Circular No. 81-11. " inadequate Decay Heat Removal Durin0 Reactor Shutdown",

6.4 INPO SOER-82-2, " inadvertent Reactor Pressure Vessel Pressurization",

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