ML20070V111
| ML20070V111 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 01/14/1983 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-SSINS-6820 IEB-82-03, IEB-82-3, NUDOCS 8302150065 | |
| Download: ML20070V111 (9) | |
Text
3 ead 1
6 TENNESSEE VALLEY AUTHORITY CH ATT ANOOG A. TENNESSEE 374o1 400 Chestnut Street Tower II 3 Jt" N P2: 07 January 14, 1983
'J.S.
Nuclear Regulatory Commission Region II ATTN: James P. O'Reilly, Regional Administrator 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303
Dear Mr. O'Reilly:
OIE BULLETIN 82 STRESS CORROSION CRACKING IN THICK WALL, LARGE DIAMETER, STAINLESS STEEL, RECIRCULATION SYSTE.4 PIPING AT BWR PLANTS - BROWNS FERRY NUCLEAR PLANT Enclosed is our complete response to IE Bulletin 82-03 for the Browns Ferry Nuclear Plant. The enclosed information supercedes that submitted by D. S. Kammer's letter to you dated December 9, 1982. Extension of the response beyond January 12, 1983, as committed to in my letter to you dated December 3, 1982, was discussed with F. Cantrell of your staff on January 12, 1983 If you have any questions, please call Jim Domer at FTS 858-2725.
To the best of my knowledge, I declare the statements contained herein are complete and true.
Very truly yours, TENNESSEE VALLEY AUT;IORITY l
L. M. Mills, Manager Nuclear Licensing Enclosure l
8302150065 830114 DR ADOCK 05000259 PDR 1ggl
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ENCLOSURE RESPONSE TO IE BULLETIN 82-03 BROWNS FERRY NUCLEAR PLANT 1.
The ultrasonic examinations specified by the subject IE bulletin were performed by Lambert, MacGill, Thomas, Inc.
(LMT) using procedures which have been demonstrated to NRC.
2.
Please see attached table.
3 Evaluation of and corrective actions for linear indications noted on welds VR-2-14 and VR-2-36 were presented to NRC on January 6,1983, and will be transmitted by a separate report before startup of the unit.
4.a.1 The isometric drawing for the unit 2 recirculation piping system at Browns Ferry is attached. There were 36 recirculation system welds examined in response to IE Bulletin 82-03 Recirculation System Welds Examined Weld No.
Size SRI N1 A (safe end) 28" 1 31 KR-2-17 12" 2.09 N1B (safe end) 28" 1 31 GR-2-14 12" 1.5?
GR-2-27 28" 0.87 KR-2-18 12" 2.39 KR-2-24 28" 1.04 GR-2-41 12" 1.93 GR-2-53 28" 1.11 GR-2-42 12" 1.72 GR-2-18 22" 1.07 KR-2-40 12" 2.42 KR-2-45 28" 1.44 GR-2-43 12" 1.71 KR-2-51 28" 1.08 GR-2-38 12" 2.76 GR-2-54 28" 1.17 GR-2-4 4"
N/A GR-2-51 22" 0.92 GR-2-33 4"
N/A GR-2-12 12" 2.81 KR-2-37 22" N/A i
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Weld No.
Size SRI GR-2-13 12" 1.60 KR-2-15 22" N/A N2C (safe end) 12" 1 71 GR-2-52 22" 0 98 N2G (safe end) 12" 1.52 GR-2-35 12" 2 71 KR-2-36 22" 1 95 KR-2-35 22" 2.65 KR-2-41 22" 2.0 KR-2-42 22" 1 91 KR-2-20 22" 0.93 KR-2-19 22" 0 96 KR-2-13 22" 1.85 KR-2-14 22" 1.84 4.a.2 Stress rule index was the basis for selection of N1 A, N1B, N2C, and N2G safe end welds, weld KR-2-45, and the ten 12-inch recirculation riser welds. The selection of welds KR-2-37 and GR-2-52 was at the request of NRC inspector, Jim Coley. The selection of weld KR-2-15 was based on previous e.xamination findings at other nuclear facilities. The remaining welds consist of those welds previously examined this outage in accordance with the ASME Section XI in-service inspection program. The 12-inch recirculation riser and 4-inch bypass stub tube welds were examined because of management's concern that they be examined during this outage. The manifold to sweepolet welds were added to the examination scope at management's request after an NRC-conducted examination of weld KR-2-36 revealed questionable indications. Weld GR-2-35 was added when examination of KR-2-36 revealed possible indications in the adjacent weld.
4.a.3 The piping materials are listed below:
9 Min.
Size Wall Material 28" 1.088" A358 Class from plate mt'l. A-240 TP 304 22" 2.088" A358 Class 1 from plate at'l. A-240 TP 304 12" 569" A358 Class 1 from plate mt'l. A-240 TP 304 4"
337" A376 TP 304 4.a.4 The occupational radiation exposure incurred by the examination team as a result of IE Bulletin 82-03 was approximately eight rem. The precautions taken to minimize radiation exposure were a radiation survey of the area to be worked in, radiation " hot spots" noted for the examiner's information, and/or a portable radiation monitor may be required if there are several hazardous radiation areas in the i
1 i
1
-3 proxinity. In addition, a slave unit was used for weld examinations to enable part of the examination team to remain outside the drywell.
4.b Examinatibbshereconductedusingthefollowingtechniques/and equipment:
1.
Ultrasonic Instrument - Nortec 131D 2.
Transducer - Harisonic Dual Element, 1 5/MHz, 450 shear wave 3
Calibration Blocks - flat blocks, A240 matarial,1-inch and 1.25-inch nominal thickness 4.
Reference Reflector percent nominal thickness Vee notches (Sawtooth) 5 Calibration Range - 2 full Vee-paths 6.
Reference Sensitivity - first ID notch set to 80 percent of full screen height 7
Scanning Sensitivity - 2x (6db) 8.
Evaluation Sensitivity - essentially 2x because procedure requires recording. of all nongeometric reflectors regardless of amplitude 9
Recording Criteria - all nongeometric reflectors, all geometric reflectors greater than 50 percent of the distance amplitude correction curve at reference sensitivity 4.c No previous examinations were conducted using the validated methodology.
4.d The examinations were conducted using equipment and techniques qualified by LMT under NRC surveillance at Battelle Columbus Laboratories. In relation to the ultrasonic examinations, the samples used in the qualification are essentially similar to the Browns Ferry piping with regard to type material, pipe wall thickness, and diameter. The weld geometry and access were considered better on the plant piping than on the qualification samples. Based on these variables, the examinations performed at Browns Ferry may be considered capable of detecting similar cracks as large or larger than those in the qualification samples. As the actual size and nature of the sample flaws are not known to TVA, a more quantitative estimate is not possible.
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I TABLE Vi EVALUATION BY REPORT l
i TVA-038 E
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WELD OR REPORT SYSTEM COMPONENT #
SCAN (S)
REMARKS 001 Recirc GR-2-43 3,4 Intermittent ID/OD Geometry i
002 Recirc KR-2-40 3,4 Intermittent ID/OD Geometry 003 Recirc GR-2-42 3,4 Intermittent ID/OD Geometry l
004 Recirc KR-2-18 3,4 Intermittent ID/OD Geometry 005 Recirc GR-2-14 3,4 Intermittent ID/OD Geometry 006 Recirc KR-2-17 3,4 Intermittent ID/OD Geometry 007 Recirc GR-2-13 3,4 Intermittent OD Gecmetry 008 Core Spray
.DCS-2-14 3
Intermittent ID/OD Geometry 4
No Scan-Valve 009 Core Spray DSCS-2-9 3,4 Intermittent ID/0D Geometry Prominent Weld Reinforcement (Crown) 010 Recirc GR-2-12 3
Intermittent ID/OD Geometry O!!
Recire CR-2-38 3,4 Intermittent ID/OD Geometry 012 Recirc GR-2-41 3,4 Intermittent ID/OD Geometry 013 Recirc N2C SE/NOZ 3,4 Intermittent ID/OD Geometry 014 Recirc N26 SE/NOZ 3,4 Intermittent ID/OD Geometry 015 RHR DSRHR-2-7 3,4 Intermittent ID/OD Geometry 016 Recire N!B-SE 3,4 Intermittent ID Geometry 017 Recirc N!A-SE 3,4 Intermittent ID/OD Geometry 018 Recirc GR-2-53 3,4 Intermittent ID/OD Geometry 019 RHR DSRHR-2-6 3,4 Intermittent ID/OD Geometry 020 Recire KR-2-45 3,4 Intermittent ID/OD Geometry 021 Recirc GR-2-54 3,4 Intermittent ID/OD Geometry 022 RHR DSRHR-2-4A 3,4 Intermittent ID/OD Geometry
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TABLE VI EVALUATION BY REPORT l
TVA-038 l
WELD OR REPORT SYSTEM COMPONENT #
SCAN (S)
REMARKS 023 RHR DRHR-2-7 No Apparent Discontinuities i
024 Recirc KR-2-51 3,4,9,11, Intermittent ID/OD Geometry 12 Includes Longitudinal Seams @ 9:00 and i
11:00:
025 Recire GR-2-27 3
No Scan - Pucp 4,11,12 Intermittent ID/OD Geometry Includes Longitudinal. Seams @ 3:00, 026 Recirc KR-2 3,4,7,8 Intermittent ID/OD Geometry 11,12,14 OD Geometry Includes Longitudinal Seams G 2:00, l
6:00, 12:00 l
027 Recire KR-2-15 3,4,7,8 Intermittent ID/OD/ Geometry I
Includes Longitudinal Seam at 1:00 028 Recire KR-2-37 3,4,9 Intermittent ID/OD Geometry Includes Longitudinal Seam @ 11:30 029 Recirc GR-2-18' No Apparent Discontinuities No Scan 3 - Crossover Includes Longitudinal Sea,m @ 11:30 030 RHR DSRHR-2-11 3,4 Intermittent ID/OD Geometry Includes Longitudinal Seam at 7:00 i
031 RHR DHS-2-1 No Apparent Discontinuities No Scan 4 - Flange 032 RHR DSHS-2-12 5
ID Geometry 033 Recirc GR-2-51 No Apparent Discontinuities 034 Recire CR-2-52 9
ID Geometry p
i Includes Longitudinal Seam @ 11:00
' 035 RWCU DRWC-2-2 No Apparent Disconcinuities f
i No Scan 4 - Valve
i TABLE VI EVALUATION BY REPORT l
TVA-038 WELD OR REPORT SYSTEM COMPONENT #
SCAN (S)
REMARKS 036 RWCU DRWC-2-1A Intermittent ID Geomecry No Scan 4 - Velve 037 Recirc GR-2-4 3,4 Intermittent ID Geometry i
038 Recirc GR-2-33 3,4 Intermittent ID Geometry J{
039 RHR DSRHR-2-9 3,4,5,6,7, Intermittent ID/OD Geometry 8,11,12, Includes Longitudinal Seams @ 3:00, 13,14 6:00, 9:00 040 RHR DSRHR-2-4 3,4,5,6, Intermittent ID/0D Geometry 11,12,14 Includes Longtudinal Seams @ 12:00 and 6:00 O
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TABLE VI EVALUATION BY REPORT TVA-039 WELD OR REPORT SYSTEM COMPONENT #
SCAN (S)
REMARKS 001 Recirc KR-2-36 3,4 Linear Indications 12:00
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4:00, 5:00 60% DAC Maximum Amplitude, Scan 3 002 Recire KR-2-14 3,4 Linear Indication, 6/5" CW of l
Longitudinal Seam, 60% DAC Maximum Amplitude, Scan 3 003 Recire KR-2-20 No Apparent Discontin,uities S'dE NOTE 1 004 Recirc KR-2-42 No Apparent Discontinuities SEE NOTE 1 005 Recire GR-2-35 Intermittent ID/0D Geometry, 360*
006 Recire KR-2-15 No Apparent Discontinuities SEE NOTE 1 007 Recirc KR-2-35 No Apparent Discontinuities SEE NOTE 2 008 Recirc KR-2-41 No Apparent Discontinuities SEE NOTE 2 009 Recirc KR-2-30 No Apparent Discontinuities NOTES:
1.
Intermittent areas of increased bas eline noise.
Possibly due to early metallurgical changes lead ng to IGSC.
2.
Increase in general " noise" level.
Increased le vel is essentially constant over entire examination.
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