ML20153C562
| ML20153C562 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 08/25/1988 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| GL-88-01, GL-88-1, NUDOCS 8809010181 | |
| Download: ML20153C562 (6) | |
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, TENNESSEE: VALLEY AUTHORITY -
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SN 157B Lookout' Place
'AUG % 51988 U.S. Nuclear Regulatory Cormuission ATTN:' Document control Desk Washington,.D.C. 20555 centlement In the Matter of
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' Docket Mos. 50-259 Tennessee. Valley Authority
) 260 50-296 BROWNS FERRY NUCLEAR PLANT (BFN) - RESPONSE TO INQUIRY 1BY NRC STAFF CONCERNING THE DISPOSITION OF WELD NUMBER DSRHR-2-SA As A RESULT OF RADIOGRAPH INDICATIONS l
l During a meeting between the NRC staff and TVA held on May 11, 1988, i
concerning Generic Letter 88-01, "NRC position on ICSCC in BWR Austenitic Stainless Steel piping," a question was raised concerning.the radiograph indications found in weld number DSRHR-2-5A.
The purpose of this letter is to provide information concerning the indications and resulting action taken.
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TVA responded to Generic Letter 84-11. "Inspections of BWR' Stainless Steel j
piping," by letter dated December 31, 1987.
In this submittal', it was reported that weld DSRHR-2-SA had been radiographed and that the radiography had revealed two linear indications, located 0.2 and 0.6-inch below the outside surface weld.
Supplemental ultrasonic examinations (UT) of the weld i
determined that the indications did not originate at the inside surface of the weld but were located between weld layers.
It was concluded that the indications were not Intergranular Stress Corrosion Cracking (IGSCC) but instead were inck of fusion between layers, with no measurable through wall dimension. The December letter stated that the weld would be left "as is".
During the course of the meeting on May 11, 1988, NRC staff asked whether the 4
j indications, with regard to weld DSRHR-2-SA, were allowable by the ASME code, and if not, what t6chnical basis was used to allow continued operation with I
this weld. In response to this question, TVA is providing the following information.
i The discovery and disposition of weld DSRHR-2-5A were documented by i
notification of indication (NOI) U2/C5-135 (see attached copy). According to
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the N01, the indications exceeded allowable ASME code limits. The weld was determined to be acceptable for continued operation by a Unreviewed :*-'r,ty Question Determination (USQD), which stated the following t
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l An Equal Opportunity Employer-
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'U.S. Nuclear Regulatory Commission
"... The linear inclusion indications in NOI U2/CS-135 appear to_be from Jack of fusion, not ICSCC. There is no appreciable through wall dimension to the indications, and they do not originate at the insido surface of the pipe.
The weld is thus acceptable, and therefore the integrity of the system is not affected."
The weld was evaluated for compliance with ASME code to support the statement above. ASME code (Section II, IWB-3514.3, 1975 Edition) allows a 10 percent through wall indication without further evaluation.
Since these indications have no appreciable through wall depth, the ASME evaluation of the subject weld found the weld acceptable. A more frequent inspection frequency (1/3 interval) is required for weld with such indications. This more frequent inspection for this weld is included in the current ISI program.
In conclusion, weld DSRHR-2-5A was found to be acceptable for continued operation without repair becauco of the nature of the indications. The indications were determined to be caused by lack of fusion between weld layers and not ICSCC. Because the indications have no appreciable thecush wall depth they are not considered to be a threat to the piping integrity.
Please refer any questions regarding this matter to Patrick Carter at (205) 729-2689.
Very truly yours, TENNESSEE VALLEY AUTHORITY w
R.
, ridley, Dir tor Nuclear Licens ng and Regulatory Affairs Enclosures cc: See page 3
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. U.S. Nuclear Regulatory Commission JG 251988 cc:
Ms. S. C. Black, Assistant Director for Projects TVA Projects Division U.S. Nuclear Regulatory Commission one Whito Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Mr. F. R. McCoy, Assistant Director for Inspection Programs TVA Projects Division U.S. Nuclear Regulatory Commission Region 11 101 Marietta Street, NW, Sutto 2900 Atlanta, Georgia 30323 Browns Ferry Resident Inspector Browns Ferry Nucioar Plant Route 12 Box 637 Athens, Alabama 35611 1
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APPENDIX D DATA SKEF.T 1.
NOTIFICATION OF INDICATION PART I - FINDINGS NOI No. 4' os'-/ g Plant / Unit 8 /A
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ExaminationReportNo.[67g/
Component ID 25'2Nk.3 1 fd
- Drawing so. CHAJ 20,K-C.
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Description of Indication: (Sketch / Photograph if needed)
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7/31/85 Attachment to N.O.1. O U2/C5-135 ER A-165091 Upon reexamining Weldment No. DSRilR-2;5A with the more sensitive "M-Film", an additional linear indication was discovered.
Examination of sector 2-3 netted small indications while sectors 3-4 and 4-5 revealed defects of a larger nature. These indications appear to be a singular anomaly running intermittently for 45 inches in the circumferential direction on the upstream fusion wall.
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