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  
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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I 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

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REVISED BY:

G.

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SUBMITTED BY:

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Reiipon ibl'e e'ction Supervisor

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PORC REVIEW DATE:

N 2I N APPROVED BY:

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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 370011 PDR ADOCK O 37 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 Revised to delete reference to SI-48, 1

AijG 2j 1985 3,9 and to clarify note.

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SQNP 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

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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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7 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

f.

Refer to ES-0.2 as. required C

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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

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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:

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1) Upper head may. void
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 l

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SQNP 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

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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

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SQNP ES-3.3 Unit 1 or 2 Page 6 of 9 Rev. 0 f

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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, THEN use one pzr PORV

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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 I(

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level < 25%,

level > 25%

THEN; 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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i SQNP 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 tap (elev. + 711'5") and S/G wide range level lower tap Cy-

  1. ~

(elev.

  • 704'8"), the pzr level and S/G. wide range level may

)f-be required to be downscale when ruptured S/G is drained.

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