ML20237J018

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Rev 1 to Emergency Instruction ES-3.3, Post-Steam Generator Tube Rupture Cooldown by Ruptured Steam Generator Depressurization
ML20237J018
Person / Time
Site: Sequoyah  Tennessee Valley Authority icon.png
Issue date: 08/21/1985
From: Patterson B, Strickland G
TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20237H133 List: ... further results
References
ES-3.3, NUDOCS 8708170462
Download: ML20237J018 (11)
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, TENNESSEE' VALLEY AUTHORITY

-SEQUOYAH NUCLEAR PLANT .

ur EMERGENCY INSTRUCTION ..

ES-3.3 POST-SGTR COOLDOWN BY RUPTURED S/G DEPRESSURIZATION ..

t Revision l ,

PREPARED BY: M. StricJcland RESPONSIBLE SECTION* Operation /

REVISED BY: G. I d' SUBMITTED BY: A Af/// o .

Reiipon ibl'e

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  • e'ction Supervisor

. PORC REVIEW DATE: N 2I N APPROVED BY:  % w[ fMr 5%

Pladt Manager DATE APPROVED: kUb 2I N Reason for revision (include all Instruction Change Form Nos.):

Revised to delete reference to SI-48, and to clarify note.

4 The last page of this instruction is number: 9

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B708170462 37001137 PDR ADOCK O P

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M SEQUOYAH NUCLEAR PLANT C PLANT INSTRUCTION REVISION LOG -

i EMERGENCY INSTRUCTION ES-3.3 ,.

REVISION Date Pages REASON FOR REVISION (INCLUDE COMMIT-LEVEL Approved Affected MENTS AND ALL ICF FORM NUMBERS) 0 10/04/84 ALL 1 AijG 2j 1985 3,9 Revised to delete reference to SI-48, and to clarify note.

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. ES-3.3 Unit 1 or 2 Page 1 of 9 Rev. O I

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POST SGTR COOLDOWN BY RUPTURED S/G DEPRESSURIZATION A. PURPOSE This guideline provides actions to cooldown and depressurize the plant to cold shutdown ' conditions following a steam generator tube rupture.

This recovery method depressurizes the ruptured S/G by using condenser dumps, blowdown, or S/G PORV.

B. SYMPTOMS None ,,

C. TRANSITION FROM OTIIER INSTRUCTIONS ES-3.1, SI Termination Following SGTR I

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SQNP ES-3.3 Unit 1 or 2 Page 2 of 9 Rev. O I

I POST SGTR COOLDOWN BY RUPTURED S/G DEPRESSURIZATION

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STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED CAUTION: This instruction should not be used unless ES-3.2, Post SGTR Cooldown Using Backfill, is inadequate. _ _ _

Management approval and 10CFR20 offsite dose evaluation must be completed prior to performing this instruction. 1 1 Establish Pzr Press Control

a. Pzr bubble established
b. Pzr liquid at saturation temp
1) Control pzr heaters as necessary

( c, Maintain RCS press at

  • , { k ruptured S/G press 2 Check If Cold Leg Accumulators Should Be Isolated
a. WHEN RCS press < 1000 psig AND STABLE, THEN:
1) Restore power to isolation valves i
2) Close cold leg accumulator 2) IF isolation valve can isolation valves NOT be closed, THEN vent any unisolated accumulator l

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'. ' SQNP ES-3.3 Unit 1 or 2 Page 3 of 9 Rev. 1 POST SGTR COOLDOWN BY RUPTURED S/G DEPRESSURIZATION STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED 3 Check Shutdown Margin During Cooldown

a. Periodically sample RCS boron concentration
b. During cooldown, borate RCS due to dilution from .

ruptured S/G 4 Initiate RCS Cooldown ,

To 350 F

$ a. Start SI-127

b. Cooldown as quickly as

{g possible but do -: exceed

  1. (' '  !

,. T-cold cooldown of 100 F in any 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />

c. Dump steam to condenser c. IF condenser NOT from intact S/Gs iivailable, THEN use intact S/G PORVs
d. Maintain intact S/G d. IF any S/G level levels s 33% Iiicreases in an uncontrolled manner, THEN go to
e. Refer to GOI-3C as required
f. Refer to ES-0.2 as . required C p

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1 SQNP ES-3.3 Unit 1 or 2 Page 4 of 9 Rev. O f ,

POST SGTR COOLDOWN BY RUPTURED S/G DEPRESSURIZATION ~

en STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBThlNED C AUTION : RCS press and ruptured S/G press must be . maintained less than ruptured S/G PORV setpoint (1040 psig).

t 5 Maintain Pzr Level Between 20% And 80% [50% And 80%

FOR ADVERSE CNTMTl .

a. Adjust charging as necessary
b. Open letdown orifice valves ,,

as necessary

c. Adjust letdown press control valve as necessary f 6 Maintain RCS Press At Ruptured

'# { k S/G Press

a. Control pzr heaters as necessary
b. Use pzr normal sprays b. IF letdown is in service, as necessary THEN use aux spray IF letdown NOT in service , j THEN use one pzr PORV and n6te following:
1) Upper head may . void 1
2) PRT may rupture 7 Check If RCS Cooldown Should Be Stopped
a. RCS temp ~< 350 F a. Continue RCS cooldown until RCS temp 5 350 F l
b. Stop RCS cooldown  ;

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, ES-3.3 Unit 1 or 2 Page 5 of 9 Rev. O f,

POST SGTR COOLDOWN BY RUPTURED S/G DEPRESSURIZATION -

STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED Note: When refilling ruptured S/G, if the S/G press increases to 1015 psig or decreases in an uncontrolled manner, then stop AFW flow to the ruptured S/G. Adjust RCS press to the ruptured S/G press.

8 Maintain Ruptured S/G Level > 25%

a. Control ruptured S/G level a. IF_ ruptured S/G between 25% and 50% level > 50%,

THEN stop AFW to ruptured S/G CAUTION: Ruptured S/G press may decrease rapidly when steam is

( released .

9 Depressurize Ruptured S/G And RCS To 380 psig

a. IF water is NOT in main a. IF condenser NOT steamlines , available ,

THEN depressurize ruptured THEN use S/G blowdown S/G using MSIV bypass and condenser dump valves IF S/G blowdown NOT available, THEN 'use ruptured j S/G PORV

b. Maintain RCS press at ruptured S/G press i 1

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SQNP ES-3.3 Unit 1 or 2

. Page 6 of 9 Rev. 0 f r I POST SGTR COOLDOWN BY RUPTURED S/G DEPRESSURIZATION

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STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED 10 Check IF RHR Can Be Placed In Service

a. Check the following:
1) RCS temp 5 350 F
2) RCS press 138C psig
b. Place RHR in service per SOI-74.1 A
c. Use RHR and intact S/G for cooldown
d. Stop depressurization of ruptured S/G f

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( 11 Check If RCPs Must Be Stopped

a. WHEN conditions for running RCPs can NOT be maintained, THEN stop RCPs  ;

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SQNP ES-3.3 Unit 1 or 2 Page 7 of 9 Rev. O POST SGTR COOLDOWN BY RUPTURED S/G DEPRESSURIZATION STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED 12 Continue RCS Cooldown To 200 F

a. Use RHR system
b. Dump stehm to condenser b. E condenser NOT from intact S/Gs available .

THEN use intact S/G PORVs 13 Start Backfilling Ruptured S/G Into RCS , , ,

a. Slowly depressurize RCS a. IF letdown is in service, below ruptured S/G press TIIEN use aux spray using normal pzr sprays IF letdown NOT in service,

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THEN use one pzr PORV

,, , and note following:

1) Upper head may void
2) PRT may rupture
b. Verify backflow
1) Pzr level increasing
2) Ruptured S/G level decreasing

, SQNP

, ES-3.3 Unit 1 or 2 Page 8 of 9

. Rev. O POST SGTR COOLDOWN BY RUPTURED S/G DEPRESSURIZATION

.. i STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED 14 Check If RCS Depressurization Should Continue

a. Pzr level < 80% a. IF pzr level > 80%,

' THEN:

1) Equahze RCS press and ruptured S/G press
2) Restore pzr level

< 80% before continuing RCS depressurization

b. Ruptured S/G b. IF ruptured S/G level > 25%

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level < 25%,

THEN; I(k 1) Equalize RCS press and ruptured S/G press

2) Restore ruptured S/G 1evel > 25%

before coniinuing RCS depressurization

c. RCS subcooling > 40 F c. I_F RCS subcooling not met, THEN reestablish RCS subcooling before continuing depressurization r'

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, ES-3.3 Unit 1 or 2 Page. 9 of 9 -

Rev. 1 C ,-

-POST SGTR COOLDOWN BY RUPTURED S/G DEPRESSURIZATION

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STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED ,.

15 Continue Backfilling Ruptured S/G Into RCS -

16 Evaluate Long term Plant Status *

a. Maintain cold shutdown
b. Consult with' plant staff ,

a ,*

g Note: In order to isolate the ruptured S/G from RCS, the ruptured -

p S/G and pzr level must be below the break elevation. Because -

A- the S/G tube sheet (elev. N 703') is below the pzr level lower

  1. tap (elev. + 711'5") and S/G wide range level lower tap
  1. ~ (elev.
  • 704'8"), the pzr level and S/G . wide range level may is Cy- )f- ,, be required to be downscale when ruptured S/G is drained.

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