ML20237J007

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Rev 1 to Emergency Instruction ES-3.2, Post-Steam Generator Tube Rupture Cooldown Using Backfill
ML20237J007
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-3.2, NUDOCS 8708170458
Download: ML20237J007 (8)
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Text

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TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT EMERGENCY INSTRUCTION l

ES-3.2 POST-SGTR COOLDOWN USING BACKFILL 4..

Revision 1 PREPARED BY:

StricklanO RESPONSIBLE SECTION:

Operatip

[

REVISED BY:

G.

kl d

SUBMITTED BY:

48/N

'hn l#

Re'sjion's le S'6 tion Supervisor

.PORC REVIEW DATE:

~AU 21Gb5 APPROVED BY:

% W( c$th Pldht ' Manager

.AUG 21 E85 DATE APPROVED:

Reason for revision (include all Instruction Change Form Nos.):

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

I 4

C.

The lart page of this instruction is number:

6 8700170450 870811 DR ADOCK O y7

SEQUOYAH NUCLEAR PLANT PLANT INSTRUCTION REVISION LOG EMERGENCY INSTRUCTION ES-3.2 REVISION Date

~

Pages REASON FOR REVISION (INCLUDE COMMIT-LEVEL _

Approved Affected MENTS AND ALL ICF FORM NUMBERS)

O_

10/04/84 ALL

^

gjg g g jgg Revised to delete reference to SI-48, 1

3,6 and to clarify note.

w l(

et 1

0274L/mbs

SQNP ES-3. 2 Unit 1 or 2 Page 1 of G Rev. O F

I

(

POST-SGTR COOLDOWN USING B ACKFILL 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 draining it through the ruptured S/G tube into the RCS.

B.

SYMPTOMS None C.

TRANSITION FROM OTHER INSTRUCTIONS ES-3.1, SI Termination Following SGTR

.c _ _ _ _ _ _ _ _ - _ _ _ _ _ _ -

SQNP ES-3.2 Unit 1 or 2 Page 2 of 6 Rev. O F

POST-SGTR COOLDOWN USING B ACKFILL STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED 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 ruptured S/G press

.c 2

Check If Cold Leg Accumulators Should Be Isolated a.

WHEN RCS press < 1000 psig AND STABLE, T11EN :

1) Restore power to isolation valves
2) Close cold leg accumulator
2) IF, isolation valve can isolation valves NOT be closed, TIIEN vent any unisolated accumulator 3

Check Shutdown Margin During Cooldown a.

Periodically sample RCS boron concentration b.

During cooldown, borate RCS due to dilution from ruptured S/G. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ -

SQNP ES-3. 2 Unit 1 or 2 Page 3 of 6 Rev. 1 lf k

POST-SGTR COOLDOWN USING BACKFILL

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STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED 4

Initiate RCS Cooldown To 200 F

^

a.

Start SI-127 b.

Cooldown a's quickly as possible but do not exceed -

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 available, THEN use intact S/G PORVs d.

Maintain intact S/G d.

IF any S/G 1evel levels s 33%

Increases in an uncontroHed manner, THEN go to

  • E-3, J

STEAM GENERATOR

'..e TUBE RUPTURE e.

Refer to GOI-3C as required f.

Refer to ES-0.2 as required 5

Adjust Pzr Level l

a.

Establish pzr level between j

20% and 30% [50% and 60%

FOR ADVERSE CNTMT]

1) Adjust charging and letdown as necessary
2) Control pzr heaters as necessary

SQNP ES-3.2 Unit 1 or 2 Page 4 of 6 Rev. O POST-SGTR COOLDOWN USING B ACKFILL 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.

O Established Ruptured S/G Level > 25%

a.

Control ruptured S/G a.

IF ruptured S/G level between 25% and 50%

level > 50%,

T11EN stop AFW to ruptured S/G 7

Start Backfilling Ruptured

(

S/G Into RCS

.e l k a

Slowly depressurize RCS a.

IF letdown is in service, below ruptured S/G press THEN use aux spray using normal pzr sprays IF letdown NOT in service, 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 l l

I SQNP ES-3.2 Unit 1 or 2 Page 5 of 6 Rev. O F\\

I POST-SGTR COOLDOWN USING B ACKFILL

(

STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED 8

Check If RCS Depressurization Should Continue a.

Pzr level < 80%

a.

IF_ pzr level > 80%,

TIIEN:

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

< 80% before continuing RCS depressurization b.

Ruptured S/G b.

I_F ruptured S/G level > 25%

level < 25%,

~

g THEN;

1) Equalize RCS press and ruptured S/G press
2) Restore ruptured S/G 1evel > 25%

before continuing RCS depressurization c.

RCS subcooling > 40 F c.

IF RCS subcooling not

)

met, l

THEN ' reestablish RCS

)

subcooling before continuing depressurization I ----------.___________o

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a SQNP ES-3.2 Unit 1 or 2 Page 6 of 6 Rev. 1 ll

\\

k-POST-SGTR COOLDOWN USING BACKFILL STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED i

9 Check IF RHR Can Be Placed Tn Service a.

Check the following:

1) RCS temp 5 350 F
2) RCS press 3 380 psig b.

Place RHR in service per SOI-74.1 A c.

Use RHR and intact S/G for cooldown 10 Check If RCPs Must Be Stopped

(

{

a.

WHEN conditions for running

.A. #

~ RCPs can NOT be maintained, THEN stop RCPs 11 Continue RCS Cooldown To 200 F 12 Continue Backfilling Ruptured S/G Into RCS 13 Evaluate Long Term Plant Status a.

Maintain cold shutdown b.

Consult with plant staff p

Note:

In order to isolate the ruptured S/G from RCS, the ruptured C

hG S/G and pzr level must be below the break elevation.

Because F

the S/G tube sheet (elev.

  • 703') is below the pzr level lower 4

tap (elev. s 711'5") and S/G wide range level lower tap 4

(elev. N 704'8"), the pzr level and S/G wide range level may be required to be downscale when ruptured S/G is drained.

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