ML20076H629
| ML20076H629 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 08/24/1983 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NCR-1188, NCR-1203, NCR-1563, NUDOCS 8309060080 | |
| Download: ML20076H629 (2) | |
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THORITY artAN gl CHdTANOOGA TENNESSEE 37401 400 Chestnut Street ower II
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Nb August 24, 1983 U.S. Nuclear Regulatory Coimaission Region II Attn:
Mr. James P. O'Reilly, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta,. Georgia 30303
Dear Mr. O'Reilly:
BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - QA BREAKDOWN - DEFICIENT FILL!rf WELDS - NCRs 1188, 1203, AND 1563 - FINAL REPORT On May 7,1980, R. W. Wright, NRC-0IE Region II, was informed that nonconformance report (NCR) 1188 was determined to be reportable in accordance with 10 CPR 50.55(e). Since that time, related NCR 1203 has been determined to be reportable in accordance with 10 CFR 50.55(e). This was followed by our interim reports dated June 6, September 19, and December 15, 1980 and March 6 and June 10, 1981. Some of the affected welds are inaccessible for inspection; therefore, NCR 1563 has been written to disposition these welds. This was followed by our interim reports dated August 27 and December 11, 1981 and March 5, May 18, and November 10, 1982.
Enclosed is our final report.
If you have any questions concerning this matter, please get in touch with R. H. Shell at FTS 858-2688.
Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, nager Nuclear Licensing Enclosure cc:
Mr. Richard C. DeYoung, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Records Center (Enclosure)
Institute of Nuclear Power Operations 1100 circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339 8309050080 830824 i
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ENCLOSURE BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 QA BREAKDOWN - DEFICIENT FILLET WELDS NCRs 1188, 1203, AND 1563 l
FINAL REPORT Description of Deficiency Numerous fillet welds located in various safety-related systems do not meet ASME Code and/or TVA Construction Specification G-29 requirements because of inadequate fillet leg size or theoretical throat dimensions. Deficient welds have been found in socket weld fittings and socket weld flanges (NCR 1188), and in component support welds (NCR 1203). This quality assurance problem is attributable in part to the procedure for fillet weld inspection because it did not accurately reflect the applicable ASME Code requirements. Additional problems with socket weld flanges arose because, at the time the procedures were written, G-29M requirements did not specify socket weld flange requirements. G-29M was revised on March 21, 1979, to include socket weld flange requirements. However, due to an oversight TVA failed to incorporate this change into its site quality control procedure (QCP). Fillet weld gauges not being available to assist the inspectors in determining the adequacy of welds also contributed to the problem.
Safety Imolications If uncorrected,., inadequate welds could. result in loss of integrity for_ pipe
_ 2 supporta and pipe pressure boundaries in cafety-r21ated syste=s, thereby adversely affecting plant safety.
1 Corrective Action NCR 1188 A total of 10,140 socket welds in 43 plant systems under the scope of NCR 1188 were identified by Dellefonte Nuclear Plant (BLN). Of this amount, 9,451 were reinspected, 673 (see NCR 1563) were embedded, and 16 more are inaccessible for inspection. NCR 1563 was written to disposition these embedded and inaccessible welds.
The total rejectable of those inspected was 668 welds equating to a total reject rate of 7.1 percent. Only 66 welds (0.7 percent) were undersized by more than 1/16-inch. A breakdown on those welds found rejectable follows:
Undersized Throat Undersized Leg Undersized Leg & Throat Together 318 271 79 All rework on accessible welds has been completed. To prevent recurrence, guidelines for accepting various welds have been added to quality control procedures and inspectors have incorporated use of weld gauges. TVA has inspected 540 socket welds that were made sometime after completion of inspector training and implementation of the use of fillet weld gauges, and no rejectable welds were found.
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NCR 1203 Two hundred randomly selected supports of the approximately 8.500 supports identified under the scope of this NCR were reinspected and data submitted to TVA Division of Engineering Design (EN DES) for evaluation. EN DES determined all welds under the scope of this NCR should be reinspected. Of the 8,500 supports to be reinspected, 2,422 were removed from~ under the scope of the NCR due to normal rework, revision changes, and deletions. The status of the remaining 6,078 supports requiring reinspection are as follows:
Number of supports inspected 6,065 (99.8%)
Number of welds inspected 21,009 13.349 (63.5%)
Number of welds accepted Number of welds rejected 7,660 (36.5%)
Number of welds reworked 7,496 (97.6%)
Number of welds remaining to be reworked (66 supports) -
164 Number of supports remaining to be inspected 10 Number of supports inaccessible for inspection 3'
Completion of remaining inspections and rework of remaining welds will be completed by October 1,1983, with the exception of 15 supports. These supports are located in the unit 2 spent fuel area and will not be accessible for rework until the fuel is transferred to the unit 1 spent fuel area which is presently scheduled for March 1984. The rework will, therefore, be completed by May 30, 1984.
'The three supports inaccessible for reinspection have been evaluated and are to be used'in~their~present configuration. ~ ~~~ -- - -
NCA 1563 Nonconformance report 1563, resulting from NCR 1188, addresses a total of 689 socket welds categorized as " inaccessible." All welds which are not embedded have been reexamined. All welds which are ambedded and are located four pipe diameters (measured axially from the point at which the pipe penetrates the concrete surface) or more from the concrate surface are acceptable. All welds which are less than four pipe diameters require an anchor plate. ECN 1656 has been completed for designing the required anchor plates.
Installation of unit 1 anchor plates will be completed by October 3.1983 Due to work emphasis on unit 1, unit 2 anchor plates will not be complete until December 30, 1985.
Action Required to Prevent Recurrence To prevent recurrerce, a procedures and training unit which nontrols the incorporation of upper tier document changes into site QCPs has been established. This is accomplished by performing a review of these documents along with a parallel review performed by affected organizations. Also, guidelines for accepting various welds have been added to quality control procedures and welding inspectors have been retrained with emphasis placed on the use of fillet weld gauges.
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