ML031820264
| ML031820264 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 05/19/2003 |
| From: | Douglas B Duke Energy Corp |
| To: | Olshan L NRC/NRR/DLPM/LPD2 |
| References | |
| TAC MB8978 | |
| Download: ML031820264 (12) | |
Text
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Leonard Olshan - Discussion-------Points
Tube Inspection Call I1-1--. - -- -, ...... ......... - I---.- -- -- - .1-1-1.1 for- ------
SG------ Page Pag- I1---
I Dsuso Leonard Qishan.11111- I.- PonsfrS Tuensec-o C-l From: *Robert C Douglaso <rcdougla~duke-energy~com>
To: <Ino~nrc.gov>
Date: 5/19/03 11:49AM
Subject:
Discussion Points for SG Tube Inspection Call The attached PDF file provides Duke's handout for the call.
Bob Douglas 864-885-3073 - Desk 864-885-3401 - FAX (See attached file: SFX4DC.pdf)
CC: 'Larry E Nicholson' <lenicholson~duke-energy.com>
Enclosure 2
OCONEE UNIT 3 STEAM GENERATOR TUBE INSPECTION DISCUSSION POINTS
- 1. Discuss whether any primary to secondary leakage existed in this unit prior to shutdown.
Response: Primary to secondary leakage at time of shutdown was less than 2 gpd and had not changed during the cycle.
- 2. Discuss the results of secondary side pressure tests.
Response: No secondary side pressure tests were conducted.
- 3. For each steam generator, provide a description of areas examined, including the expansion criteria utilized and type of probe used in each area. Also, be prepared to discuss your inspection of the tube within the tubesheet, particularly the portion of the tube below the expansion/transition region.
Response: Scope of the Inspection Is shown on the attachment A. The expanded region of the tube Is inspected with qualified Plus-Pt from the roll transition to the tube end.
- 4. Discuss any exceptions taken to the industry guidelines.
Response: One exception to SG Examination Guidelines, Rev 5 concerning the volumetric inspection of 1-690 rolled plugs. ONS-3 S!Gs are scheduled for replacement at EOC-21 In fail of 2004 and I-690 rolled plugs will not exceed 10.2 EFPY. 1-690 rolled plugs have been inservice for significantly longer periods with no degradation observed. Visual exams have been completed for all plugs with no Indications of leakage or movement.
- 5. Provide a summary of the number of indications identified to-date of each degradation mode and steam generator tube location (e.g., tube support plate, top-of-tubesheet, etc.). Also provide information, such as voltages, and estimated depths and lengths of the most significant indications.
DRAFT I
Response: Below is the number of tubes plugged for categories shown:
3A OTSG 3B OTSG Capture Locations 19 9 Tube Defects IGA 13 41 Wear 0 0 Freespan SCCAIGA 330 100 Roll Transition PWSCC 15 32 Impingement 22 6 Dent SCC 1 1 Misc. 10 6 Dentlol Combination 4 7 Sleeve 1 1 Total Plugged 3EOC-20 415 203 Total Cumulative Plugged 1580 1018 10.2% 6.6%
Details of the depth, length and voltage will be provided In future report of inspection findings.
- 6. Describe repair/plugging plans for the SG tubes that meet the repair/plugging criteria.
Response. All tubes meeting the plugging criteria are being repaired by plugging with exception of Indications in the original rolled transition In upper tube sheet which can be repaired with reroll repair approved for ONS. Reroll repairs have been performed as follows:
SIG 3A: 19 tubes reroll repaired that were left In service SIG 3B: 27 tubes reroll repaired that were left In service
- 7. Discuss the previous history of SG tube inspection results, including any "look backs" performed. Specifically for significant indications or indications where look backs are used in support of dispositioning (e.g., manufacturing burnish marks).
Response: All bobbin Indications will have Plus-Pt exam and will be dispositioned based on this result. Previous data Is not used directly in dispositioning process for ONS units.
DRAFT 2
- 8. Discuss, in general, new inspection findings (e.g., degradation mode or location of degradation new to this unit).
Response: No new degradation mechanism has been seen. Current active mechanisms for ONS-3:
- a. Tube Support Plate Fretting Wear (None Plugged this outage)
- b. Inpingement
- c. ODIGA In tubesheet crevice and freespan
- d. PWSCC In upper tubesheet rolls, dents, and plugs
- f. Sleeve IGA/SCC In expansion transitions
- 9. Discuss your use or reliance on inspection probes (eddy current or ultrasonic) other than bobbin and typical rotating probes, if applicable.
Response: Standard bobbin and plus point probes were used as listed In Attachment 1.
- 10. Describe in-situ pressure test plans and results, if applicable and available, including tube selection criteria.
Response: Following Is the number of tubes identified for in-situ testing. Al testing followed EPRI guidelines for hold times. Maximum pressure was approx. 4300 psig, which represents 3 times normal delta-P plus adjustments for testing.
3A OTSG 3B OTSG Number Tested 12 (axial Indications) 1 (axial Indications)
Results No Leakage No Leakage
- 11. Describe tube pull plans and preliminary results, if applicable and available; include tube selection criteria.
Response: No plans for pulling a tube were identified.
- 12. Discuss the assessment of tube integrity for the previous operating cycle (i.e.,
condition monitoring).
Response: No significant primary to secondary leakage existed or occurred during the past operating cycle. Results of In-situ testing Indicate that no tubes exceeded structural acceptance criteria at the end of this cycle.
- 13. Provide the schedule for steam generator-related activities during the remainder of the current outage.
Response: All eddy current Inspections are complete, In-situ pressure tests are completed and tube plugging is in progress.
DRAFT 3
- 14. Once Through Steam Generators - if you have Babcock and Wilcox (B&W) welded plugs installed in the steam generators, be prepared to discuss the actions taken in response to Framatome's notification of the effect of tubesheet hole dilation on the service life of B&W welded plugs.
Response: Framatome ANP analyzed the allowed heatup/cooldown cycles for each plug type. It was verified that the service life limits would not be exceeded prior to SG replacements, which are scheduled for the next refueling on each unit. All repair products used, except those listed below, are fully qualified for original 40 year operating life.
Plug Type # Plugs-ONS3 Allowed Cycles Current Cycles OEM Welded Plugs 14 205 87 Remote Welded Plugs 136 33 11 Taper Welded 43 205 67
- 15. Once Through Steam Generators - describe your inspection/plugging plans with respect to the industry identified severed tube issue (NRC Information Notice (IN) 2002-02 and IN 2002-02, Supplement 1).
Response: The severed tube Issue was addressed for ONS-3 during the previous outage EOC-19. As a result of additional Information on tubes plugged with OEM welded plugs, the tubes below are being captured by surrounding with plugged/stabilized tubes. These tubes had welded plugs Installed pre-service with the tube potentially violated and not stabilized.
SIG3A: 4 tubes SIG 3B: 3 tubes
- 16. If steam generators contain thermally treated tubing (Alloy 600 or 690), discuss actions taken (if any) based on Seabrook's recent findings (Reference Information Notice (IN) 2002-21)?
Response: All the tubing on ONS-3 Is 1-600 sensitized tubing In straight lengths and would not be subject to degradation similar to Seabrook.
DRAFT 4
Attachment A: OCONEE NUCLEAR STATION STEAM GENERATOR INSPECTION AND MAINTENANCE WORKSCOPE Unit: 3 EOC: 20 Quantities ACTIVITY S/G A SIG B BASIS / COMMENTS PROBES
___ C/I H/L C/L __ _
1.0 ECT Tube Examinations 1.1 Bobbin (full length) 14,294 14,716 100% in-service tubes 0.510 dia Mid-1.2 RPC Special Interest 2, 12 1,773 All bobbin indications 0.460, and 0.400 All dings. diameter Plus-Pt 1.3 RPC Lane & Wedge 222 212 100% tubes surrounding the 0.460 dia. Plus-Pt.
_sleeved region 2 rows around 1.4 RPC Rolls - UTS 14,026 14,475 100% in service tubes less 0.460 dia. Plus-Pt.
_ __________________ _ ______ ______ _______ _______ sleeved 1.5 RPC Rolls - at 0 0 100% Re-rolled InManufacture 0.460 dia. Plus-Pt.
Manufacture 1.6 RPC Re-roll UTS 135 260. 100 % of re-rolled locations 0.460 dia. Plus-Pt.
1.7 RPC Kidney Area 2070 2132 100 % from top of tubesheet plus 2 Inch
__________________ ______ ______ ______ Minus 12 inches below the LTS DRAFT 5
2.0 Plug & Sleeve Exams - - - I I I I 2.1 RPC Rolled Plugs - I 15 66 11 44 1-600 100% H/L and C/L 1600 _
RPC Rolled Plugs - I 1690 see exception 690 2.2 RPC Thimble Plugs - 29 -40% of total In 3A _
2.3 Bobbin - Sleeves 268 241 _ 100% In-service sleeves 0.410 dia. bobbin 2.4 RPC - Sleeves 268 241 100% in-service sleeves at roll 0.400 dia. Plus-Pt.
_ _ _ _ _ ___ jo ints 3.0 ECT Testing of
____ Repairs 3.1 Current Outage Re- 22 28 100% Bobbin profilometry and rolls _ RPC 3.2 Current Outage 0 0 No sleeves installed Sleeves 4.0 Visual Exams 4.1 Rolled Plugs 1088 1097 748 756 100% for leakage and damage 4.2 Welded Plugs 53 46 49 45 100% for leakage and damage 4.3 Sleeve Plugs 24 N/A 18 N/A 100% for Indications of leakage 4.4 Ribbed Plugs 0 22 0 14 100% for Indications of leakage 4.5 Explosive Plugs N/A N/A N/A N/A 1l00% for indications of leakage _ _l_
4.6 Thimble Plugs 165 1____ 11 815 815 TOTAL plug visuals 1165 1165 1815 85 ____________ ________
DRAFT 6
4.7 Internals Inspection BWOG Internals Degradation l__________ _ - _ Assessment this RFO 4.8 Internal FDW header Not required for Unit 3 this insp. l outage 4.9 Tube/TSP/TS None Inspection l 4.10 Skewed Tube Complete in previous outage Verification _
5.0 Plug Repalrs -
5.1 Ribbed Plugs N/A N/A N/A N/A 5.2 Rolled Plug removal 0 0 0 1 1-600 based on ECT 5.3 Welded Plugs 0 0 0 0 None Required 5.4 Explosive Plugs 0 0 0 0 None Required_
5.5 Thimble Plugs 0 0 0 0 None Required 6.0 Tube Repairs _
6.1 Rolled Plugs ._
new 415 415 203 203 Includes tubes to 'capture' Replacements 0 0 0 1
=__ sleeve plugs 5 N/A 3 N/A Stabilizers 35 4 20 2 6.2 Re-Rolls 22 28 6.3 Sleeves I._ -- None Installed DRAFT 7
6.4 Tube End Repair As req'd for plug/stabilizer Insertion & in-situ 7.0 Other Tests (non-ECT) 7.11.
At shutdown . None due to leakage < 2gpd Prior to start-up INone required 7.2 In-situ Pressure Test 12 1 All axial indications, no leakage 8.0 Primary MaIntIPM -
8.1 Manways- V V Y .
removal/reinstall.
8.2 Nozzle dams- Y Y installation 9.0 Secondary - N N N N MaintUPM 9.1 Sludge Lancing N N N N 9.2 Internals Inspection N N N N 9.31FOSAR N N N N _
- 9. FDW Riser leak N N N N repairs I DRAFT8 8
Pane 1 4 Leynard - ONS-3 steam generators Qishan NRC question-- ON§,-jAtaTgenerators Leunard O1shjp,-,Nf1q,_question -Page- I From: "Robert C Douglas" <rcdougla~duke-energy.com>
To: <Ino~nrc.gov>
Date: 5/20/03 2:40PM
Subject:
NRC question - ONS-3 steam generators The info requested by Emmett in our 5/19 call is provided below.
Bob Douglas 864-885-3073 - Desk 864-885-3401 - FAX
Forwarded by Robert C Douglas/Gen/DukePower on 05/20/2003 02:30 PM James H Batton To: Robert C Douglas/GenrDukePower aDukePower, William 05/20/2003 02:17 M Sample/Gen/DukePower@ DukePower PM cc: Judy E SmithlGenlDukePower@DukePower
Subject:
NRC question - ONS-3 steam generators Bob, Below is Blake Lowery's response to Emmett Murphy's 5/19 conference call question regarding the circ indication in the Lower Tubesheet of 3A steam generator tube 132-81.
Please forward this response to Emmett.
I will provide a copy of this response to Jerry Blake, Region II, who is currently on site.
Jim Batton Phone: 864 885-3893
Forwarded by James H Batton/Gen/DukePower on 05/20/2003 01:52 PM Bryce B Lowery Jr I 0: James H Batton (Gen/DukePower, William M 05/20/2003 01:40 Sample/Gen/DuikePower PM cc:
Subject:
NRC question The circ indication was in an 11 volt dent. The indication PDA is 35% with a load carrying ability in excess of 4000 lbs. This is well above the worst case MSLB load of 2870 Ibs. If you assume it to leak, the MSLB leakage is calculated to be well below the maximum allowable of 1 gpm.
Leorard Olshan - Re: Fwd: Revised follOWU Page 1 From: 'Robert C Douglas' <rcdougla duke-energy.com>
To: 'Leonard Olshan' <LNO@nrc.gov>
Date: 5/22/03 1:18PM
Subject:
Re: Fwd: Revised followup The attached PDF file below provides our response.
Bob Douglas 864-885-3073 - Desk 864-885-3401 - FAX (See attached file: SFX5AC.pdf)
"Leonard Olshan'
<LNO@nrc.gov> To: <rcdouglaZduke-energy.com>
cc:
05t21/2003 10:41
Subject:
Fwd: Revised followup AM
Message from 'Emmett Murphy' <ELM nrc.gov> on Wed, 21 May 2003 10:40:32 -0400-To: "Leonard Olshan' <LNO.owf4_po.OWFN_DO@nrc.gov>
Subject:
Revised followup Lenny, I've reconsidered. My follow up questions for Oconee are limited to the following:
I would like to get a little more detail on measured depth and length of the circumferential crack in tube 132-81 and a brief explanation as to how they determined the axial load capacity at the cracked cross section.
NRC Ouestion re ECr Indication in ONS-3 SG A:
[Provide] a little more detail on measured depth and length of the circumferential crack in tube 132-81 and a brief explanation as to how they determined the axial load capacity at the cracked cross section.
Duke Response:
The indication measured 0.96 inches in circumferential extent with a range of depths from 19% to 98% throughwall.
The following is a summary of the axial force equations from the EPRI Flaw Handbookl The total axial force that can be resisted by a straight tube in an OTSG with circumferential degradation is given by the following equation, FA =(Sy+S)7tRmtFNX where FN is given by the smaller of, FN =1.02514 -2.13295 +2.241114 42 0.90909 43, or, FN =1.2128 (m ) ( ) where PDA 100 When tube rotation is effectively prevented, as for circumferential cracking well within the tubesheet crevice, the latter equation for FN is appropriate. When tube rotation is limited but not effectively prevented by the presence of lateral tube supports, as for circumferential cracking in the freespan, the first equation for FN includes a limited bending effect in addition to direct tensile loading. Both equations are based on experimental data for steam generator tubing with circumferential EDM slots.