ML20155C265
| ML20155C265 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 10/29/1998 |
| From: | Alexion T NRC |
| To: | NRC (Affiliation Not Assigned) |
| References | |
| NUDOCS 9811020168 | |
| Download: ML20155C265 (15) | |
Text
,.
October 29, 1998 l
MEMORANDUM TO: PD IV-1 File FROM:
Tom Alexion ORIGINAL SIGNED BY
SUBJECT:
STEAM GENERATOR INSPECTION RESULTS, OCTOBER 1998, SOUTH TEXAS PROJECT, UNIT 2 The NRC staff had a conference call with the licensee on October 15,1998, to discuss the results of the steam generator inspections. The licensee provided the information in to facilitate the October 15,1998, conference call. On October 20,1998, the licensee provided an update to the information provided on October 15,1998. That information is Attachment 2. The purpose of this memorandum is to place the attachments in the Public Document Room.
Docket No. 50-499 Attachments: As stated DISTRIBUTION:
Docket File (50-499)
PUBLIC DOCUMENT NAME: G:\\STPFINAL\\ST101598.MEM To receive a copy of this document, indicate in the box C= Copy w/o attachment / enclosure E= Copy with attachment / enclosure N = No copy D:Ph k Tale 3M CHawes DAN JHarbo_n(
f OFFICE PSPO4TT E
LA:PD41 E
NAME DATE
[D f y /98
/0 /O 4 /98 h
/98 OFFICIAL F4ECORD COPY o{
l 9811020168 981029 G
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PDR ADOCK 05000499 gg, l
NRC PHONE DISCUSSION - 2RE06 STEAM GENERATOR TUBE INSPECTION RESULTS 3
OCTOBER 1998 1.
Primary to Secondary leakage prior to shutdown.
STP 2RE06 - Leak rate prior to shutdown was a fraction of a gallon per day.
2.
Results of secondary side hydro.
STP 2RE06 - STP does not routinely perfomi secondary side hydros during steam generatorinspections. Eddy current testing of tubes and visualinspection of previously installed plugs are employed to ensure primary-to-secondary integrity, in this outage, one previously installed mechanical plug was found with an excessive amount of boron crystals, indicating a possible lack of pressure integrity. The tube had been plugged for a small DSI/SAI in 2RE05, so if the plug was leaking during the cycle, it would not have directly resulted in a primary-to secondary leak. Installation records for j
this plug were reviewed, and no anomalies were noted. A welded plug was installed below this plug.
4 3.
For each SG, provide a general description of areas examined, include expansion j
criteria and specify type of probe used in each area.
I STP 2RE06 -This was the first STP Unit 2 inspection where the voltage-based repair l
criteria was applied. The Inspection Plan was the same for all SGs:
l 100% bobbin fulllength j
= 100% H/L Top-of-tubesheet by RPC 100% Row 1 & 2 U-bend by + Point j
. Minimum sample of 20% of Freespan dings by + Point - Expansion to 100% in voltage j
steps.
I 4.
For analyzed EC results, describe bobbin indications (those not examined with RPC) and RPC/Plus Point /Cecco indications. Include the following information:
location, number, degradation mode, disposition, and voltages / depths / lengths of l
the most significant indications.
I
{
STP 2RE06 -The only bobbin indications not examined with RPC are as follows:
DSis less than 1 volt (per voltage based repair criteria) l Unsampled cing:: under 5 volt & MBMs that are unchanged from the baseline i
AVB/Preheater wear indications i
i i
E ATTACHMENT 1 1
I
4.
(STP 2RE06 Centinued)
Inspection results are as follows:
PROBABLE DEGRADATION MODES FOR TUBES TO BE PLUGGED NO C PROB. DEG MODE SG 2A SG 2B SG 2C SG 2D -
TOTAL TSP ODSCC*'*
- 16 5
10 7
38 Free Span ODSCC 3
1 3
2 9
Loose Part Wear"v'*3 2*'**
2
~
Miscellaneous ** *
- 1 mie*
1 me=4 2
TOTAL:
19 7
16 9
51 NOTE 1 - Plugging lists have been issued for SGs 2C & 2D; data for SGs 2A & 2B is preliminary.
NOTE 2 - Confirmed DSis greater than one volt (APC lower voltage repair limit).
NOTE 3 - Adjacent tubes with volumetric indications at top-of-tubesheet; no part present.
NOTE 4 -This was a U-bend indication (possible MBM) which has changed since the baseline.
No circumferential cracks identified.
No defects identified in Row 1 & 2 U-bend examination i
No indications identified in the + Point free span ding sample which were not identified by bobbin.
l Some preliminary unchecked information relevant to voltage-based repair criteria application (all SGs):
~1197 tube with DSI indications were left in service with bobbin voltage below the lower voltage repair limit (1.0 volt).
No PWSCC @ TSPs, no cire cracks @ TSPs, no axialindications extending outside l
the TSP have been detected.
Conditional Burst Probability & EONC Leakage calculations not completed yet (required prior to mode 4). No difficulties expected in meeting voltage-based repair criteria limits.
5.
Describe repair / plugging plans.
STP 2RE06 - All defects are/will be plugged, no sleeving this outage. See inspection Results Table above. Plugging is complete in SG 20 & SG 2D.
6.
Discuss previous history; "look backs" performed.
STP 2RE06 - Look backs performed on all freespan DNis (dings with possible flaw indications) & freespan NQls (non-quantifiable indications), to confirm no change from the baseline.
i i
4 l
4040 *d 8628 246 2iS ON!SN331"I W313nN
- 2:0i 866T-ST-130
7.
Discuss new inspection findings.
STP 2RE06 - No new degradation mechanisms identified.
8.
Describe in-situ pressure test plans and results, if available; include tube selection criteria.
STP 2RE06-In-situ test plans were developed consistent with EPRI guidelines. No pressure tests performed.
9.
Describe tube pull plans and preliminary results,if available; include tube selection criteria.
STP 2RE06 -Tube selection criteria is per Generic Letter 95-05. Two tubes are to be pulled from SG 2A. Tube sections removed willinclude all intersections up to the fourth tube support plate. The selected tubes include the largest dominant single axial crack found at tube-to-tube support plate intersections in this outage (4.03 volts bobbin) at the second tube support plate in SG 2A.
TUBE PULL
SUMMARY
Tube TTS FDB TSP 1 TSP 2 TSP 3 TSP 4 R18C100 NOD NDD DSI DSI NDD NDD (1.25 V)
(4.03 V) l R19C83 NDD NDD DSI DSI NDD NDD (2.76 V)
(0.24 V)
Tube R19083 is from the high incidence area of Unit 1 top of tubesheet cire, cracking.
All of the DSis listed confirmed as dominant single axial cracks by RPC.
Both of these tubes are very close to the locations of tubes pulled previously in Unit 1.
10.
Assessment of tube integrity for previous operating cycle.
STP 2RE06 - As of this moming's analysis no tube defects have been found that l
challenge tube structural integrity.
11.
Assessment of tube integrity for next operating cycle.
STP 2RE06 - No conditions are expected that would impede full cycle operation.
12.
Provide schedule for steam generator-related activities during remainder of current outage.
STP 2RE06 - Data acquisition and analysis is complete at this time.
Plugging lists will be complete by 10/15.
Plugging will be complete by 10/16.
Tube pulls will be complete by 10/16 Manways will be installed 10/18 (@ midloop).
Mode 4 projected on 10/20.
40&O'd -@M@ M E3 GFBPX5LM6S N
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BACKGROUND INFORMATION ON STP UNIT 2:
Commercial Operation: 6/89 EFPY at 2RE06: 6.7 EFPY Model: Westinghouse Model E
)
Tube Material: Alloy 600, mill annealed Tube Support Plates: Stainless Steel, w/ drilled holes Tubesheet expansion: hydraulic Tw-2.93 EFPY at 623'F; 620'F since.
ID has been shot peened: hot leg after first cycle & cold leg after second cycle.
U bend heat treatment R1 & R2 prior to initial operation.
Previous plugging history:
602 tubes plugged in 2RE05 (voltage-based repair criteria NOT implemented)
Total tubes plugged per SG prior to 2RE06:
2A - 146 2B - 186 20 - 170 2D - 180 TOTAL: 682 l
l l
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I 1
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._ 40fSO'd, e628 246 ETS. ____
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_.SE 01, 0661-ST-1DO
South Texas Preiset Unit 2 As of 0300 en 10/15/98 2RE06 Eddy Current Daily Status Report SG-A SG-B SG-C SG-D TOTAL COLD LEG BOBBIN PROGRAM
- 1. PLANNED TESTS 4499 4678
'4474 4464 18115
- 2. ACQUIRED TESTS 4499 4678 4474 4464 18115
- 3. RESOLVED TESTS 4499 4678 4474 4464 18115 HOT LEG BOBBIN PROGRAM
- 1. PLANNED TESTS 459 239 459 457 1614
- 2. ACQUIRED TESTS 459 239 459 457 1614
- 3. RESOLVED TESTS 459 239 459 457 1614 HOT LEG TUBESHEET RPC PROGRAM
- 1. PLANNED TESTS 4718 4678 4694 4684 18774
- 2. ACQUIRED TESTS 4718 4678 4694 4684 18774
- 3. RESOLVED TESTS 4718 4678 4694 4684 18774 U BEND RPC PROGRAM
- 1. PLANNED TESTS 240 239 239 237 955
- 2. ACQUIRED TESTS 240 239 239 237 955
- 3. RESOLVED TESTS 240 239 239 237 955 I
HOT LEG SPECIAL INTEREST RPC PROGRAM
- 1. PLANNED TESTS 37 42 42 31 152
- 2. ACQUIRED TESTS 37 42 42 31 152
- 3. RESOLVED TESTS 37 42 42 31 152 i
l COLD LEG SPECIAL INTEREST RPC PROGRAM l.
- 1. PLANNED TESTS 13 36 29 24 102
- 2. ACQUIRED TESTS 13 36 29 24 102 3 RESOLVED TESTS 13 36 29 24 102 f
HOT LEG DING PROGRAM
- 1. PLANNED TESTS 31 34 28 37 130
- 2. ACQUIRED TESTS 31 34 28 37
- 130,
- 3. RESOLVED TESTS 31 34 28 37 130 COLD LEG DING PROGRAM
- 1. PLANNED TESTS 38 26 29 33 126
- 2. ACQUIRED TESTS 38 26 29 33 126
- 3. RESOLVED TESTS 38 26 29 33 126 i
Page 1 of 2 t
40/90*d 8628_246 ETS BMt@@W1 f3bTt539 fS;ML_fyg % Asp
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Scutn iexas t'rojict unit e as vi v4vv en sui swco 2RE06 Eddy Current Daily Status Report SG-A SG-B SG-C SG-D TOTAL HOT LEG U-BEND DING PROGRAM
- 1. PLANNED TESTS 18 10 10 10 48
- 2. ACQUIRED TESTS 18 10 10 10 48
- 3. RESOLVED TESTS 18 10 10 10 48 COLD LEG U-BEND DING PROGRAM
- 1. PLANNED TESTS 7
4 10 10 31
- 2. ACQUIRED TESTS 7
4 10 10 31
- 3. RESOLVED TESTS 7
4 10 10 31 BOBBIN PROGRAM - BOTH LEGS
- 1. TUBES W/INDS 1-19% TW 10 13 11 17 51
- 2. TUBES W/INDS 20-39% TW 2
5 4
2 13
- 3. TUBES W/INDS > = 40% TW 0
0 0
0 0
- 4. TUBES W/DSI < = 1.0 VOLTS 152 400 359 286 1197
- 5. TUBES W/DSI 1.0 - 3.30 VOLTS 21 3
10 7
41
- 6. TUBES W/DSI > 3.30 VOLTS 1
0 0
0 1
- 7. TUBES W/OTHER l-CODE INDS 21 45 33 18 117 HOT LEG TUBESHEET RPC
- 1. TUBES W/ AXIAL INDS O
O
_0 0
0
- 2. TUBES WITH CIRC & MMI INDS O
O O
O O
- 3. TUBES WITH VOLUMETRIC INDS 0
1 2
0 3
HOT LEG SPECIAL INTEREST RPC
- 1. TUBES W/ AXIAL INDS 16 5
10 8
39
- 2. TUBES WITH CIRC & MMIINDS O
O O
O O
- 3. TUBES WITH VOLUMETRIC INDS O
O O
O O
COLD LEG SPECIAL INTEREST RPC
- 1. TUBES W/ AXIAL INDS 3
1 3
0 7
- 2. TUBES WITH CIRC & MMI INDS O
O O
O O
l
- 3. TUBES WITH VOLUMETRIC INDS O
O 1
2 3
l
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i
}
Distribution:
Chet McIntyre, STPNOC Kevin Miller, Westinghouse j
Copy to Data Management files I
(
e Page 2 of 2
-e e e
_ - - w e, _,. m ee
Tom Alexion /lan Bameo
.l Attached is an update of the handout which was faxed for the phone call on 10/15/98. Below is a summary of the changes, which are marked with change bars. Please distribute to the others that were in the call. If you have any further questions, let me know and we'll arrange another call. Thank you.
A ro-2d-9 4 Chet McIntyre Summary of Changes:
Question 1 Response - Added information on calculated leak rate during preceding cycle, as requested. Included attachment Question 4 Response, Probable Degradation Modes Table - Changed classification of one tube from Miscellaneous to Loose Part Wear. Previously, Note 4 was incorrectly applied to this tube.
Note 5 was added to explain the new classification. Also added the cold leg indication discussed in the 10/16 phone call, with corresponding Note 6.
Question 4 Response, NOTE 1 - Updated to reflect completion of final plugging list.
Question 4 Response, NOTE 3 - Added clarification that the two adjacent tubes are peripheral tubes. This was mentioned in the phone call.
Question 4 Response, bullets following the Notes - Added statement that no DSis were found at Flow Distributon Baffles (FDBs) & statement that no DSis were found on the cold leg. This was discussed in the phone call.
Question 4 Response, bullets following the Notes - Deleted the note about preliminary, unghecked information; Added statement to the effect that final DSI counts would be included in the 90 day report. They are not expected to vary significantly from the number given here.
Question 5 Response - Updated to reflect completion of plugging.
Question 9 Response - Amended the Tube Puli Summary Table and the preceding paragraph to correct a misstatement. The fourth tube support plate intersection is NOT included.
Question 9 Response. Amended the second bullet following the Tube Pull Summary Table to correct a misstatemeni Only three of the fcur DSis @ pulled intersections actually confirmed, not all four as previously stated.
Question 10 Response - Updated to reflect current outage status.
Question 12 Response - Updated to reflect current outage status.
Updated the attached "2RE06 Eddy Current Daily Status Report" to the FINAL version (dated 10/17/98).
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NRC PHONE DISCUSSION -2RE06 STEAM GENERATOR TUBE INSPECTION RESULTS OCTOBER 1998 l
1.
Primary to Secondary leakage prior to shutdown.
STP 2RE06 - Leak rate prior to shutdown was a fraction of a gallon per day. Calculated leak rate with with stable tritium concentration in the primary was ~0.25 gpd, but never exceeded ~0.8 gpd during the cycle. See attached graph.
l 2.
Results of secondary side hydro.
STP 2RE06 - STP does not routinely perform secondary side hydros during steam generator inspections. Eddy current testing of tubes and visualinspection of previously installed plugs are employed to ensure primary-to-secondary integrity.
in this cutage, one previously installed mechanical plug was found with an excessive amount of boron crystals, indicating a possible lack of pressure integrity. The tube had r
been plugged for a small DSI/SAI in 2RE05, so if the plug was leaking during the cycle, it would not have directly resulted in a primary-to-secondary leak. Installation records for this plug were reviewed, and no anomalies were noted. A welded plug was installed below this plug.
3.
For each SG, provide a general description of areas examined, include expansion criteria and specify type of probe used in each area.
STP 2RE06 -This was the first STP Unit 2 inspection where the voltage-based repair criteria was applied. The Inspection Plan was the same for all SGs:
100% bobbin fulllength 100% H/L Top-of-tubesheet by RPC l
100% Row 1 & 2 U-bend by + Point
. Minimum sample of 20% of Freespan dings by + Point-Expansion to 100% in voltage
- steps, l
4.
For analyzed EC results, describe bobbin indications (those not examined with l
RPC) and RPCIPlus Point /Cecco indications. Include the following information:
location, number, degradation mode, disposition, and voltages / depths / lengths of the most significant indications.
l STP 2RE06 -The only bobbin indications not examined with RPC are as follows:
DSis less than 1 volt (per voltage based repair criteria)
Unsampled dings under 5 voit & MBMs that are unchanged from the baseline l
AVB/Preheater wear indications s
l l
6040 *d 86ES Ed,6 EIS DN!SN3311 W373rN TT:PT 866I-9E-100
- _ _ _ _ _ ~ - -
n
- - ~
4.
(STP 2RE06 Continued)
Inspection results are as follows:
PROBABLE DEGRADATION MODES FOR TUBES TO BE PLUGGED"'*
PROB. DEG MODE SG 2A SG 2B SG 2C SG 2D TOTAL TSP ODSCC"W
16 5
10 7
38 Free Span ODSCC 3
1 4""'**
2 10 Loose Part Wear 1 "* ' "
- 2"* ' *
- 3 Miscellaneous 1"v'**
1 TOTAL:
19 7
17 9
52 NOTE 1 - Plugging lists have been issued for all SGs.
NOTE 2 - Confirmed DSis greater than one volt (APC lower voltage repair limit).
NOTE 3 - Adjacent peripheral tubes with volumetric indications at top-of-tubesheet; no part present.
NOTE 4 -This was a U-bend indication (possible MBM) which has changed since the l
baseline.
l NOTE 5 - Peripheral tube with shallow wear near tubesheet NOTE 6 - One of these defects is at 22C Support Plate (Preheater), but is believed to have originated in freespan above and below the plate - discussed with NRC (call coordinated by Tom Alexion) on 10/16/98.
No circumferential cracks identified.
l l
No defects identified in Row 1 & 2 U-bend examination No indications identified in the + Point free span ding sample which were not identified by bobbin.
No DSIs at flow distribution baffle (FDB) intersections.
No DSis on cold leg intersections (seen Note 6 above).
-1197 tubes with DSI indications were left in service with bobbin voltage below the lower voltage repair limit (1.0 volt). Final data to be provided in 90 day report.
?
No PWSCC @ TSPs, no cire cracks @ TSPs, no axialindications extending outside the TSP have been detected.
Conditional Burst Probability & EONC Leakage calculations not completed yet (required prior to mode 4). No difficulties expected in meeting voltage-bau d repair l
criteria limits.
{
5.
Describe repair / plugging plans.
STP 2RE06 - All defects are/will be plugged, no sleeving this outage. See Inspection Results Table above. Plugging is complete in all SGs.
l l
6.
Discuss previous history; "look backs" performed.
STP 2RE06 - Look backs performed on all freespan DNis (dings with possible flaw indications) & freespan NQIs (non-quantifiable indications), to confirm no change from l
the baselin.
1 secref esas ets Eis omssaan wrens 22:,2 essi-ez_.too
- 7.
Di cuss new inspection findings.
STP 2RE06 - No new degradation mechanisms identitied.
8.
Describe in-situ pressure test plans and results, if available; include tube selection criteria.
STP 2RE06-In-situ test plans were developed consistent with EPRI guidelines. No pressure tests performed.
9.
Describe tube pull plans and preliminary results, if available; include tube selection criteria.
i STP 2RE06 - Tube selection criteria is per Generic Letter 90-05. Two tubes are to be pulled from SG 2A. Tube sections removed willinclude all intarsections up to the fourth tube support plate. The selected tubes include the largest doirinant single axial crack j
found at tube-to-tube support plate intersections in this outage (4.03 volts bobbin) at the second tube support plate in SG 2A.
TUBE PULL
SUMMARY
Tube TTS FDB TSP 1 TSP 2 TSP 3 TSP 4 R18C100 NDD NDD DSI DSI NDD NDD (1.25 V)
(4.03 V)
R19C83 NDD NDD DSI DSI NDD NDD (2.76 V)
(0.24 V)
Tube R19083 is from the high incidence area of Unit 1 top of tubesheet cire. cracking.
All of the DSis listed confirmed as dominant single axial cracks by RPC.
Both of these tubes are very close to the locations of tubes pulled previously in Unit 1.
10.
Assessment of tube integrity for previous operating cycle.
STP 2RE06 - As of this moming's analysis no tube defects have been found that challenge tube structural integrity.
11.
Assessment of tube integrity for next operating cycle.
STP 2RE06 - No conditions are expected that would impede full cycle operation.
12.
Provide schedule for steam generator-related activities during remainder of current outage.
STP 2RE06 - Data acquisition and analysis is complete at this time.
Plugging lists will be complete by 10/16.
Plugging will be complete by 10/16.
Tube pulls will be complete by 10/16 Manways will be installed 10/18 (@ midloop).
Mode 4 projected on 10/20.
40/PO*d 8628 E46 ZIS ONISN3317 W37 DON SE:01 8661-51-100
BACKGROUND INFORMATION ON STP UNIT 2:
CommercialOperation: 6/89 EFPY at 2RE06: 6.7 EFPY Model: Westinghouse Model E Tube Material: Alloy 600, mill ar.nealed 1
Tube Support Plates: Stainless Steel, w/ drilled holes Tubesheet expansion: hydraulic Tw -2.93 EFPY at 623*F; 620'F since.
l ID has been shot peened: hot leg after first cycle & cold leg after second cycle.
i U bend heat treatment R1 & R2 prior to initial operation.
Previous plugging history:
602 tubes plugged in 2RE05 (voltage-based repair criteria NOT implemented) l Total tubes plugged per SG prior to 2RE06:
2A-146 l
2B - 186 2C - 170 2D - 180 TOTAL: 682 l
l I
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40/$0*d 8628 E46 EIS ON!SN3311 W373nN SE:0I 866I-ST-l'T)
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S:uth Taxis Prd2ct Unit 2 As cf 0300 en 10/15/98 2RE06 Eddy Currsnt Dilly Status R; port 1.
SG-A SG-B SG-C SG-D TOTAL COLD LEG BOBBIN PROGRAM
- 1. PLANNED TESTS 4499 4678 4474 4464 18115
- 2. ACQUIRED TESTS 4499 4678 4474 4464 18115 l
- 3. RESOLVED TESTS 4499 4678 4474 4464 18115_
HOT LEG BOBBIN PROGRAM
- 1. PLANNED TESTS 459 239 459 457 1614
- 2. ACQUIRED TESTS 459 239 459 457 1614
- 3. RESOLVED TESTS 459 239 459 457 1614 HOT LEG TUBESHEET RPC PROGRAM
- 1. PLANNED TESTS 4718 4678 4694 4684 18774
- 2. ACQUIRED TESTS 4718 4_678 4694 4684 18774
- 3. RESOLVED TESTS 4718 4678 4694 4684 18774 U. BEND RPC PROGRAM
- 1. PLANNED TESTS 240 239 239 237 955
- 2. ACQUIRED TESTS 240 239 239 237 955 l3. RESOLVED TESTS 240 239 239 237 955 HOT LEG SPECIAL INTEREST RPC PROGRAM
- 1. PLANNED TESTS 37 42 42 31 152
- 2. ACQUIRED TESTS 37 42 42 31 152
- 13. RESOLVED TESTS 37 42 42 31 152 COLD LEG SPECIAL INTEREST RPC PROGRAM
- 1. PLANNED TESTS 13 36 29 24 102
- 2. ACQUIRED TESTS 13 36 29 24 102
- 3. RESOLVED TESTS 13 36 29 24 102 HOT LEG DING PROGRAM
- 1. PLANNED TESTS 31 34 28 37 130
- 2. ACQUIRED TESTS 31 34 28 37 130 3 RESOLVED TESTS 31 34 28 37 130 COLD LEG DING PROGRAM
- 1. PLANNED TESTS 38 26 29 33 126 j
- 2. ACQUIRED TESTS 38 26 29 33 126 1
- 3. RESOLVED TESTS 38 26 29 33 126 l
l l
Page 1 of 2 40/90*d 8628 246 EIS DNISN33!l NO31DnN SE:0T 866T-SI-130
40*d 10101 Scuth scxts Pr: Ject unit e as vi vovv en avisores 1
2RE06 Eddy Curtsnt Dilly Ststus Rep:rt SG A SG-B SG-C SG-D TOTAL HOT LEG U-BEND DING PROGRAM
- 1. PLANNED TESTS 18 10 10 10 48
- 2. ACQUIRED TESTS 18 10 10 10 48
- 3. RESOLVED TESTS 18 10 10 1 10 48 COLD LEG U-BEND DING PROGRAM
- 1. PLANNED TESTS 7
4 10 10 31
- 2. ACQUIRED TESTS 7
4 10 10 31
- 3. RESOLVED TESTS 7
4 10 10 31 BOBBIN PROGRAM - BOTH LEGS
- 1. TUBES W/INDS 1-19% TW 10 13 11 17 51
- 2. TUBES W/INDS 20-39% TW 2
5 4
2 13
- 3. TUBES W/INDS > = 40% TW 0
0 0
0 0
- 4. TUBES W/DSI < = 1.0 VOLTS 152 400 359 286 1197
- 5. TUBES W/DSI 1.0 - 3.30 VOLTS 21 3
10 7
41
- 6. TUBES W/DSl > 3.30 VOLTS 1
0 0
0 1
- 7. TUBES W/OTHER l-CODE INDS 21 45 33 18 117 HOT LEG TUBESHEET RPC
- 1. TUBES W/ AXIAL INDS 0
0 0
0 0
- 2. TUBES WITH CIRC & MMI INDS 0
0 0
0 0
- 3. TUBES WITH VOLUMETRIC INDS O
1 2
0 3
HOT LEG SPECIAL INTEREST RPC
- 1. TUBES W/ AXIAL INDS 16 5
10 8
39
- 2. TUBES WITH CIRC & MMIINDS 0
0 0
0 0
- 3. TUBES WITH VOLUMETRIC INDS 0
0 0
0 0
COLD LEG SPECIAL INTEREST RPC
- 1. TUBES W/ AXIAL INDS 3
1 3
0 7
- 2. TUBES WITH CIRC & MMIINDS O
O O
O O
- 3. TUBES WITH VOLUMETRIC INDS 0
0 1
2 3
Distribution:
Chet McIntyre, STPNOC Kevin Miller, Westinghouse Copy to Data Management files Page 2 of 2 40/40*d 8628 246 ETS DNISN3")!1 8037DnN SE:0T 8661-SI-100
Tom Alexion /lan Bames l
Attached is an update of the handout which was faxed for the phone call on 10/15/98. Belowis i
a summary of the changes, which are marked with change bars. Please distribute to the others that were in the call. If you have any further questions, let me know and we'll arrange another call. Thank you.
I W
10 %
Chet McIntyre
(
Summary of Changes:
Question 1 Response - Added information on calculated leak rate during preceding cycle, as requested. included attachment Question 4 Response, Probable Degradation Modes Table - Changed classification of one tube from Miscellaneous to Loose Part Wear. Previously, Note 4 was incorrectly applied to this tube.
Note 5 was added to explain the new classification. Also added the cold leg indication discussed in the 10/16 phone call, with corresponding Note 6.
Question 4 Response, NOTE 1 - Updated to reflect completion of final plugging list.
Question 4 Response, NOTE 3 - Added clarification that the two adjacent tubes are peripheral tubes. This was mentioned in the phone call.
Question 4 Response, bullets following the Notes - Added statement that no DSis were found at Flow Distribution Baffles (FDBs) & statement that no DSis were found on the cold leg. This was discussed in the phone call.
Question 4 Response, bullets following the Notes - Deleted the note about preliminary, l
unchecked information; Added statement to the effect that final DSI counts would be included in the 90 day report. They are not expected to vary significanty frem the number given here.
Question 5 Response - Updated to reflect completion of plugging.
Question 9 Response - Amended the Tube Pull Summary Table and the preceding paragraph to correct a misstatement. The fourth tube support plate intersection is NOT included.
Question 9 Response - Am' ended the second bullet following the Tube Pull Summary Table to correct a misstatement. Only three of the four DSis @ pulled intersections actually confirmed, not all four as previously stated.
Question 10 Response - Updated to reflect current outage status.
Question 12 Response - Updated to reflect current outage status.
Updated the attached *2RE06 Eddy Current Daily Status Report" to the FINAL version (dated i
10/17/98).
t ATTAC& LENT 2 60/E0*d 86E8 Ed,6 ETS ONISN3311 hiu37DnN TT:PT 866T-02-DO
NRC PHONE DISCUSSION - 2RE06 STEAM GENERATOR TUBE INSPECTION RESULTS OCTOBER 1998 1.
Primary to Secondary leakage prior to shutdown.
STP 2RE06 - Leak rate prior to shutdown was a fraction of a gallon per day. Ca' ulated leak rate with with stable tritium concentration in the primary was ~0.25 gpd, but never exceeded ~0.8 gpd during the cycle. See attached graph.
2.
Results of secondary side hydro.
STP 2RE06 - STP does not routinely perform secondary side hydros during steam generator inspections. Eddy current testing of tubes and visualinspection of previously Installed plugs are employed to ensure primary-to-secondary integrity.
In this outage, one previously installed mechanical plug was found with an excessive amount of boron crystals, indicating a possible lack of pressure integrity. The tube had t
been plugged for a small DSI/ sal in 2RE05, so if the plug was leaking during the cycle, it l
would not have directly resulted in a primary-to-secondary leak. Installation records for this plug were reviewed, and no anomalies were noted. A welded plug was installed below this plug.
3.
For each SG, provide a general description of areas examined, include expansion criteria and specify type of probe used in each area.
STP 2RE06 - This was the first STP Unit 2 inspection where the voltage-based repair criteria was applied. The inspection Plan we.s the same for all SGs:
100% bobbin fulllength i
100% H/L Top-of-tubesheet by RPC 100% Row 1 & 2 U-bend by + Point
. Minimum sample of 20% of Freespan dings by + Point-Expansion to 100% in voltage steps.
4.
For analyzed EC results, describe bobbin indications (those not examined with RPC) and RPCIPlus Point /Cecco indications. Include the following information:
location, number, degradation mode, disposition, and voltagesidepths/ lengths of the most significant indications.
STP 2RE06 -The only bobbin indications not examined with RPC are as follows:
DSis less than 1 volt (per voltage-based repair criteria)
Unsampled dings under 5 voit & MBMs that are unchanged from the basellne AVB/Preheater wear indications s
s 60/E0*d B628 Ed,6 EiS ONISN331'1 W3 OnN TT:P1 8661-03-1JO
4.
(STP 2RE06 Continued) n-Inspection results are as follows:
PROBABLE DEGRADATION MODES FOR TUBES TO BE PLUGGED"'*
PROB. DEG MODE SG 2A SG 2B SG 2C SG 2D TOTAL TSP ODSCC"v
16 5
10 7
38 Free Span ODSCC 3
1 4 "" ' *
- 2 10 Loose Part Wear 1""'**
2""'**
3 Miscellaneous 1"v'**
1 TOTAL:
19 7
17 9
52 NOTE 1 - Plugging lists have been issued for all SGs.
NOTE 2 - Confirmed DSis greater than one voit (APC lower voltage repair limit).
NOTE 3 - Adjacent peripheral tubes with volumetric indications at top-of-tubesheet; no part present.
NOTE 4 -This was a U-bend indication (possible MBM) which has cha"ged since the baseline.
NOTE S - Peripheral tube with shallow wear near tubesheet NOTE 6 - One of these defects is at 22C Support Plate (Preheater), but is believed to have originated in freespan above and below the plate - discussed with NRC (call coordinated by Tom Alexion) on 10/16/98.
No circumferential cracks identified.
No defects identified in Row 1 & 2 U bend examination No indications identified in the + Point free span ding sample which were not identified by bobbin.
No DSts at flow distribution baffle (FDB) intersections.
No DSis on cold leg intersections (seen Note 6 above).
=
~1197 tubes with DSI indications were left in service with bobbin voltage below the lower voltage repair limit (1.0 volt). Final data to be provided in 90 day report.
e No PWSCC @ TSPs no circ cracks @ TSPs, no axialindications extending outside the TSP have been detected.
Conditional Burst Probability & EONC Leakage calculations not completed yet e
(required prior to mode 4). No difficulties expected in meeting voltage-based repair criteria limits.
5.
Describe repairlplugging plans.
STP 2RE06 - All defects are/will be plugged, no sleeving this outage. See Inspection Results Table above. Plugging is complete in all SGs.
l 6.
Discuss previous history; "look backs" performed.
STP 2RE06 - Look backs performed on all freespan DNis (dings with possible flaw indications) & freespan NQls (non-quantifiable indications), to confirm no change from the baseline.
6040 *d 86ES E46 EIS DN!SN331"I W373nN IT:PT 8661-0E-10o
l 7.
Discuro n:w insp;cticn finding 3.
STP 2RE06 - No new degradation mechanisms identified.
8.
Describe in situ pressure test plans and results,if available; include tube selection criteria.
STP 2RE06 -In-situ test plans were developed consistent with EPRI guidelines. No pressure tests performed.
9.
Describe tube pull plans and preliminary results,if available; include tube selection criteria.
STP 2RE06 -Tube selection criteria is per Generic Letter 95-05. Two tubes are to be pulled from SG 2A. Tube sections removod willinclude all intersections up to and including the third tube support plate. The selected tubes include the largest dominant single axial crack found at tube-to-tube support plate intersections in this outage (4.03 volts bobbin) at the second tube support plate in SG 2A.
TUBE PULL
SUMMARY
Tube TTS FDB TSP 1 TSP 2 TSP 3 R18C100 NDD NDD DSI DSI NDD (1.25 V)
(4.03 V)
R19C83 NDD NDD DSI DSI NDD (2.76 V)
(0.24 V)
Tube R19C83 is from the high incidence area of Unit 1 top of tubesheet cire. cracking.
All of the DSis listed confirmed as dominant single axial cracks by RPC except the 0.24v DSI at TSP 2 in R19C83.
Both of these tubes are very close to the locations of tubes pulled previously in Unit 1.
10[
Assessment of tube integrity for previous operating cycle.
STP 2RE06 - No tube defects were found that challenged tube structuralintegrity.
l 11.
Assessment of tube integrity for next operating cycle.
STP 2RE06 - No conditions are expected that would impede full cycle operation.
12.
Provide schedule for steam generator-related activities during remainder of current outage.
STP 2RE06 - Data acquisition and analysis is complete at this time.
Plugging lists are complete.
Plugging is complete.
Tube pulls are complete.
Manways have been installed.
Mode 4 projected on 10/21.
60/S0*d 86E8 246 ETS ONISN30 n hf037DnN ET:PT B66T-02-100
~-
~
BACKGROUND INFORMATION ON STP UNIT 2:
l CommercialOperation: 6/89 l
EFPY at 2RE06: 6.7 EFPY Model: Westinghouse Model E Tube Material: Alloy 600, mill annealed Tube Support Plates: Stainless Steel, w/ drilled holes l
Tubesheetexpansion: hydraulic l
Tw - 2.93 EFPY at 623'F; 620*F since.
l lD has been shot peened: hot leg after first cycle & cold leg after second cycle.
U bend heat treatment R1 & R2 prior to initial operation.
Previous plugging history:
L 602 tubes plugged in 2RE05 (voltage-based repair criteria NOT implemented)
Total tubes plugged per SG prior to 2RE06:
l ZA-146 l
2B - 186 2C - 170 l
2D - 180 TOTAL: 682 f
i l
~
l 4
i 1
l l
60/90*d 8628 EL6 EI$
ON!SN3311 W3 OnN Et:PT 866I-03-130
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Unit Two Primary and Secondary Tritium and Leak Rate E
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0.0 81 -M AY-199B 1 - AUG-19931 -NOV-199E l -F EB-19981 -M AY-199EB 1 - AUS-1998 t
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Date
(
E RCS H (
SEC H-3 l
LK RATE S
h
South Texas Project Unit 2 As of 1435 en 10/17/es 2RE06 Eddy Current Daily Status Report FINAL SG A SG B SG C SG-D TOTAL COLD LEG BOBBIN PROGRAM
- 1. PLANNED TESTS 4499 4678 4474 4464 18115
- 2. ACQUIRED TESTS 4499 4678 4474 4464 18115
- 3. RESOLVED TESTS 4499 4678 4474 4464 18115 HOT LEG BOBBIN PROGRAM
- 1. PLANNED TESTS 459 239 459 457 1614
- 2. ACQUIRED TESTS 459 239 459 457 1614
- 3. RESOLVED TESTS 459 239 459 457 1614 HOT LEG TUBESHEET RPC PROGRAM
- 1. PLANNED TESTS 4718 4678 4694 4684 18774
- 2. ACQUIRED TESTS 4718 4678 4694 4684 18774
- 3. RESOLVED TESTS 4718 4678 4694 4684 18774 U BEND RPC PROGRAM
- 1. PLANNED TESTS 240 239 239 237 955
- 2. ACQUIRED TESTS 240 239 239 237 955 l
- 3. RESOLVED TESTS 240 239 23G 237 955 HOT LEG SPECIAL INTEREST RPC PROGRAM l
- 1. PLANNED TESTS 37 42 42 31 152
- 2. ACQUIRED TESTS 37 42 42 31 152
- 3. RESOLVED TESTS 37 42 42 31 152
~
r COLD LEG SPECIAL INTEREST RPC PROGRAM
- 1. PLANNED TESTS 13 36 29 24 102
- 2. ACQUIRED TESTS 13 36 29 24 102 36 29 24 102 l
- 3. RESOLVED TESTS 13 l
HOT LEG DING PROGRAM i
31 34 28 37 130
- 1. PLANNED TESTS 31 34 28 37 130
- 2. ACQUIRED TESTS 31 34 28 37 130
- 3. RESOLVED TESTS COLD LEG DING PROGRAM 38 26 29 33 126
- 1. PLANNED TESTS 38 26 29 33 126
- 2. ACQUIRED TESTS 38 26 29 33 126
- 3. RESOLVED TESTS n....
.4 %
60/90*d 8629 E46 EIS DN!SN30Il W TDnN
.EI:PT 8661-02-100
.60 a moi r.
South Texas Project Unit 2 As of 1435 on 10/17/98 2RE06 Eddy Current Daily Status Report FINAL SG-A SG-B SG-C SG-D TOTAL HOT LEG U BEND DING PROGRAM
- 1. PLANNED TESTS 18 10 10 10 48
- 2. ACQUIRED TESTS 18 10 10 10 48
- 3. RESOLVED TESTS 18 10 10 10 48 l
COLD LEG U-BEND DING PHOGRAM
- 1. PLANNED TESTS 7
4 10 10 31
- 2. ACQUIRED TESTS 7
4 10 10 31
- 3. RESOLVED TESTS 7
4 10 10 31 3
BOBBIN PROGRAM - BOTH LEGS
}
_1. TUBES W/INDS 1-19% TW 9
11 11 17 48 f
l
- 2. TUBES W/INDS 20-39% TW 2
5 3
2 12 l
- 3. TUBES W/INDS > = 40% TW 0
0 0
O O
i
- 4. TUBES W/DSI < = 1.0 VOLTS 152 401 359 286 1198
- 5. TUBES W/DSI 1.0 - 3.30 VOLTS 18 3
10 7
38
- 6. TUBES W/DSI > 3.30 VOLTS 1
O O
O 1
- 7. TUBES W/OTHER l CODE INDS 21 40 34 18 113 l
HOT LEG TUBEShlEET RPC
- 1. TUBES W/ AXIAL INDS 0
0 0
0 0
- 2. TUBES WITH CIRC & MMI INDS O
O O
O O
- 3. TUBES WITH VOLUMETRIC INDS O
1 2
0 3
J HOT LEG SPECIAL INTEREST RPC
- 1. TUBES W/ AXIAL INDS 16 5
10 8
39
- 2. TUBES WITH CIRC & MMI INDS 0
0 0
0 0
- 3. TUBES WITH VOLUMETRIC INDS O
O O
O O
COLD LEG SPECIAL INTEREST RPC
- 1. TUBES W/ AXIAL INDS 3
1 3
0 7
- 2. TUBES WITH CIRC & MMI INDS 0
0 0
0 0
- 3. TUBES WITH VOLUMETRIC INDS 0
0 1
2 3
Distribution:
Chet McIntyre, STPNOC Kevin Miller, Westinghouse Copy to Data Management files o
9 a# 1 60/60*d 96E9 246 ETS ONISN3317 W373nN Et:Pt 966T-02-100
..