NL-20-0417, Refueling Outage 1R29 Steam Generator Tube Inspection Report
| ML20108F618 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 04/17/2020 |
| From: | Gayheart C Southern Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-20-0417 | |
| Download: ML20108F618 (7) | |
Text
~ Southern Nuclear April17, 2020 Docket No.:
50-348 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Cheryl A. Gayheart Regulatory Affairs Director Joseph M. Farley Nuclear Plant-Unit 1 3535 Colonnade Parkway Birmingham, AL 35243 205 992 5316 cagayhea@southemco. com NL-20-0417 Refueling Outage 1 R29 Steam Generator Tube Inspection Report Ladies and Gentlemen:
In accordance with the requirements of Joseph M. Farley Nuclear Plant Technical Specification 5.6.1 0, Southern Nuclear Operating Company submits the enclosed report of the steam generator tube inspections performed during the twenty-ninth outage on Unit 1 (1 R29).
This letter contains no NRC commitments. If you have any questions, please contact Jamie Coleman at 205.992.6611.
Cheryl A.
ayh art Regulatory Affairs Director CAG/dsp/sm
Enclosure:
1 R29 Steam Generator Tube Inspection Report cc:
Regional Administrator, Region II NRR Project Manager-Farley Nuclear Plant Senior Resident Inspector-Farley Nuclear Plant RTYPE: CFA04.054
Joseph M. Farley Nuclear Plant - Unit 1 Refueling Outage 1 R29 Steam Generator Tube Inspection Report Enclosure 1 R29 Steam Generator Tube Inspection Report
Enclosure to NL-20-0417 1 R29 Steam Generator Tube Inspection Report JOSEPH M. FARLEY NUCLEAR PLANT -UNIT 1 1R29 STEAM GENERATOR TUBE INSPECTION REPORT The Joseph M. Farley Nuclear Plant (Farley)- Unit 1 Refueling Outage 29 (1R29) was conducted after steam generator (SG) service equivalent to 4.05 effective full power years (EFPY) from the previous SG eddy current inspections. No tube leakage was reported during this operating interval comprised of cycles 27, 28, and 29. No tubes were plugged during Farley 1R29. Based on SG eddy current and visual inspection data, there are two existing degradation mechanisms in the Farley Unit 1 Replacement Steam Generators (RSGs). The existing degradation mechanisms are:
Mechanical Wear at Anti-Vibration Bar (AVB) Tube Supports Mechanical Wear at Tube Support Plate (TSP) Intersections A.
The Scope of Inspections Performed on Each Steam Generator:
The inspection program, as required by EPRI PWR SG Examination Guidelines, addressed the potential and existing degradation mechanisms for Farley Unit 1 RSGs. The defined scope for Farley Unit 1 implemented during refueling outage 1R29 included the following:
- 1. Bobbin Exams (all 3 SGs) 100% full length tube-end to tube-end except Row 1 U-bends
- 2. Array Probe Examinations (all3 SGs)
Tubesheet periphery 3-tubes deep, tube-end to first support No-tube lane Rows 1-3, tube-end to first support Select tubes from tube-end-hot (TEH) to the top support on the cold leg (07C) for SGA only acquired for potential deposit mapping analyses Sample of hot leg inner bundle tubes ( ~9% ), tube end to first support hot (01H)
All bulge (BLG) in SGC and all BLG in SGA and SGB between the tube-end
+ 10 inch to the top of tube sheet (TTS)
All new A VB and TSP wear ~ 10% through wall (TW)
All dents and dings~ 2.0 Volts Affected and bounding tubes for foreign objects identified
- 3. + Point rotating pancake coil (RPC) (all 3 SGs) 100% Row 1 U-bend regions, seventh support hot (07H)-1.0" to seventh support cold (07C)-1.0" Sample of tubes to bridge the gap between Array and +Point' including:
o Dent/Dings (DNT/DNG) > 5 Volts o All DNT/DNG in SGC tube 42-72 E-1
Enclosure to NL-20-0417 1 R29 Steam Generator Tube Inspection Report
- 4. Primary Side Visual Inspections (all 3 SGs)
SG channel head bowl cladding and internal surfaces in accordance with Westinghouse NSAL-12-1, which consisted of the entire channel head internal surfaces, namely the entire tubesheet, cladding, divider plate, and associated welds/components.
- 5. Secondary Side Inspections (all 3 SGs)
TTS water lancing Visual inspections and Foreign Object Search and Retrieval (FOSAR) on all foreign objects identified Post-lancing TTS visual inspections to assess material condition, structural integrity, deposit accumulation and foreign objects, including:
o Annulus region and no-tube lane o Inner bundle passes in the sludge region (every 5th column)
B.
Active Degradation Mechanisms Found:
Anti-Vibration Bar (AVB) Wear During 1R29, there were no new indications of AVB wear identified. AVB wear was identified only in SGC tube Row 38 Column 59. In this tube, five AVB wear indications were identified with bobbin depths ranging from 7% TW to 20% TW.
Based on the inspection data structural integrity requirements have been met at the 1R29 inspection. The complete listing of A VB wear indications are in Table 1.
Tube Support Plate (TSP) Wear TSP wear was identified in all Farley SGs. Between all three SGs, twenty-five TSP wear indications were identified, in total, with bobbin depths ranging from 3%TW to 14%TW. The bobbin inspection program performed identified two new wear indications in two different tubes and twenty-three previously identified wear indications in nineteen different tubes. Based on the inspection data structural integrity requirements have been met at the 1 R29 inspection. The complete listing of TSP wear indications is in Table 2.
C.
Nondestructive Examination Techniques Utilized for Each Degradation Mechanism Degradation Mechanism(s)
Probe EPRIETSS Bobbin 96041.1 (Rev. 6) App. I AVB Wear Array 17909.2 (Rev. 1) App. I TSP/Flow Distribution Baffle Bobbin 96004.1 (Rev. 13)
Wear E-2
Enclosure to NL-20-0417 1 R29 Steam Generator Tube Inspection Report Degradation Mechanism(s)
Probe EPRIETSS Array 11956.1 (Rev 3)
Bobbin 27091.2 (Rev. 2) 27901.1 (Rev. 1) 27902.1 (Rev. 2) 27903.1 (Rev. 1)
+Point' 27904.1 (Rev. 2) 27905.1 (Rev. 2) 27906.1 (Rev. 1) 27907.1 (Rev. 2) 17901.1 (Rev. 0)- Ax.
Foreign Object Wear 17901.3 (Rev. 0)- Cir.
17902.1 (Rev. 0)- Ax.
17902.3 (Rev. 0)- Cir.
17903.1 (Rev. 0)-Ax.
Array 17903.3 (Rev. 0)- Cir.
17904.1 (Rev. 0)- Ax.
17904.3 (Rev. 0)- Cir.
17905.1 (Rev. 0)-Ax.
17905.3 (Rev. 0)- Cir.
17906.1 (Rev. 0)- Ax.
17906.3 (Rev. 0)- Cir.
D.
Location, Orientation (if linear) and Measured sizes (if available) of Service Induced Indication Table 1: Farley 1R29 AVB Wear Indications-Bobbin SG Row Column Indication 0/o TWD c
38 59 TWD 7
c 38 59 TWD 15 c
38 59 TWD 19 c
38 59 TWD 20 c
38 59 TWD 11 TWD - Through Wall Depth I Volumetric Indication Sizing A V#- Location of A VB intersection with the tube
% TWD - Percent Through-wall Depth E-3 Location AV1 AV2 AV3 AV4 AV5
Enclosure to NL-20-0417 1 R29 Steam Generator Tube Inspection Report Table 2: Farley 1R29 TSP Wear Indications-Bobbin SG Row Column Indication 0/o TWD A
1 20 TWD A
1 20 TWD A
1 20 TWD A
1 41 TWD A
1 75 TWD A
1 75 TWD A
3 4
TWD A
46 37 TWD B
1 7
TWD B
1 22 TWD B
1 76 TWD B
2 1
TWD B
2 77 TWD B
4 2
TWD B
4 2
TWD B
4 70 TWD B
6 1
TWD B
30 55 TWD B
46 53 TWD c
1 34 TWD c
1 45 TWD c
1 74 TWD c
4 2
TWD c
10 4
TWD c
16 4
TWD TWD-Through Wall Depth I Volumetric Indication Sizing
% TWD - Percent Through-wall Depth 8
8 5
10 4
8 8
5 7
4 10 4
6 4
5 5
5 5
6 5
14 9
5 4
3 Location 04C 05C 06C 06C 05C 06C 05C 05H 06C 05C 06C 04C 05C 04C 05C 05C 05H 03H 07H 06C 05C 06C 05C 04H 05C O#C/O#H =Location at TSP intersection with the tube on the hot and cold leg E.
Number of Tubes Plugged During the Inspection Outage There were no tubes plugged during the 1R29 refueling outage.
E-4
Enclosure to NL-20-0417 1 R29 Steam Generator Tube Inspection Report F.
Total Number or Percentage of Tubes Plugged to Date Table 3: Farley Unit 1 SG Plugged Tubes SG Number of Tubes plugged in Total tubes Percent tubes 1R29 plugged plugged A
3592 0
0 0%
B 3592 0
0 0%
c 3592 0
0 0%
Total 10776 0
0 0°/o G.
The results of Condition Monitoring, including the results of Tube Pulls and In-Situ Testing.
Based on the inspection data, A VB wear and TSP wear were the only active degradation mechanism observed in 1R29. No indications of AVB and TSP wear were found to be in excess of the condition monitoring limits. No tubes exhibited degradation that required in situ pressure testing and there was no primary to secondary leakage prior to the end of the inspection interval. During the SG channel head bowl visual examination, there were no abnormal conditions identified. No secondary side tube damage was attributed to the foreign objects identified from 1R29 top oftubesheet visual inspections and FOSAR. The SG performance criteria for operating leakage and structural integrity were confirmed to have been satisfied for the preceding Farley Unit 1 RSG operating interval.
E-5