ML20237J007
| ML20237J007 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 08/21/1985 |
| From: | Patterson B, Strickland G TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML20237H133 | List:
|
| References | |
| ES-3.2, NUDOCS 8708170458 | |
| Download: ML20237J007 (8) | |
Text
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s.
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
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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.
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et 1
0274L/mbs
SQNP ES-3. 2 Unit 1 or 2 Page 1 of G Rev. O F
I
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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
'..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
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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
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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
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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
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{
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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