ML20044D884
| ML20044D884 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 05/14/1993 |
| From: | Freeland L DUQUESNE LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| ND3MNO:3454, NUDOCS 9305210057 | |
| Download: ML20044D884 (5) | |
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'Af Duquesne Light 1...p_. -, _
Nutnear Group P O Box 4 Sheppmgport. FA 15077-0004 j
r May 14,1993 ND3MNO:3454 i
Beaver Valley Power Station, Unit No.1 Docket No. 50-334, Licensee No. DPR-66 Soecial Report i
United States Nuclear Regulatory Commission Document Control Desk i
Washington, DC 20555 Gentlemen:
In accordance with Appendix A, Beaver Valley Technical Specification 4.4.5.5,
" Steam Generators", the following Special Report is submitted. This report documents the results of the Inservice Inspection of the steam generator tubes, performed during the Ninth Refueling Outage.
On May 2,1993, the inservice inspection of the tubing in steam generators RC-l' E-IA (S/G A), RC-E-1B (S/G B), and RC-E-1C (S/G C) was completed.
One hundred percent (100%) of all active steam generator tubes were scheduled for bobbin coil eddy current examination as part of the initial steam generator inspection scope of l
work. The examinations in the "B" steam generator were designated as those required to meet. Technical Specification surveillance requirements.
The bobbin coil 3
examination identified fifteen (15) " defective" tubes requiring removal from service per i
Technical Specification requirements. Although this number does not necessitate a C-3 categorization, and subsequent expansion of examination scope, the previously stated j
initial sample plan accommodated a one hundred percent (100%) examination of all active tubes.
In addition, specialized supplemental examinations [i.e. motorized rotating pancake coil (MRPC) and U-bend MRPC] were performed on distorted signal indications (DSIs) and on row I and 2 U-bends. In the "B" steam generator, an additional 182 tubes were removed from service based on supplemental examination j
and conservative Beaver Valley Power Station eddy current analysis guidelines.
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May 14,1993 ND3MNO:3454 Page 2 Greater than seventy percent (70%) of the indications requiring removal of tubes from senice were identified at the hot leg tube support plate intersections. The probable defect mechnism for these tube degradation's is Outside Diameter Stress Corrosion Cracking (ODSCC). This is based on the metallurgical results from an examination of a tube that was removed during the Eighth Refueling Outage. All defective tubes have been plugged and Beaver Valley will continue with boric acid addition to the secondary plant water. The boric acid causes the tube-to-support plate crevices to become less basic and thereby reduces the propensity for ODSCC.
In addition to the above tube examinations,100% of the B&W cold leg plugs fabricated from Inconel 600 were examined. The examination revealed crack-like indications in the plugs of heat #2848. All thirty-five (35) plugs of heat #2848 (20 in i
"B" steam generator, and 15 in "C" steam generator) were replaced. Additionally, one (1) plug from the "A" steam generator (heat #W592) was replaced because it was found hanging below its originally rolled position. All plugs of heat #W592 were re-rolled as a remedial action. Another plug (heat #7042) was replaced in the hot leg side of the "B" steam generator due to crack-like indications being observed during namination of the plugs. One hundred percent of all plugs of heat #7042 were examined as a result of this indication. No other indications were observed. All replacement plugs were fabricated from Inconel 690 material.
The following table is provided as a summary of the Ninth Refueling Outage steam generator inspection results:
l S/G A S/G B S/G C Tubes inspected this outage 2882 3086 3144 t
Tubes plugged this outage 221 197 150 i
Previously plugged 506 302 244 Total tubes plugged 727(21.5 %) 499(14.7 %) 394(11.6 %)
B&W plugs replaced 1
21 15 l
(included in total above) i 4
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May 14,1993 ND3MNO:3454 Page 3 The NSSS Vendor (Westinghouse) has analyzed for an increased plugging limit of 30 percent. This revised plugging limit will be implemented prior to returning to power from the Ninth Refueling Outage. The current limit is 20 percent in any single steam generator.
,f((,[deue S' L. R. Freeland j
General Manager Nuclear Operations JGT/sl
May 14,1993 ND3MNO:3454 Page 4 i
i Mr. T. T. Martin, Regional Administrator l
United States Nuclear Regulatory Commission Region 1 475 Allendale Road King of Prussia, PA 19406 Mr. G. E. Edison, BVPS Licensing Project Manager United States nuclear Regulatory Commission Washington, DC 20555 i
Larry Rossbach, Nuclear Regulatory Commission, J
BVPS Senior Resident Inspector J. A. Holtz, Ohio Edison 76 S. Main Street i
Akron, OH 44308 Larry Beck i
Centerior Energy 6200 Oak Tree Blvd.
Independence, OH 44101-4661 l
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INPO Records Center 700 Galleria Parkway l
Atlanta, GA 30339-5957 i
Mr. Robert Barkanic Department of Environmental Resources P.O. Box 2063 16th Floor, Fulton Building Harrisburg, PA 17120 S
Director, Safety Evaluation & Control Virginia Electric & Power Co.
P.O. Box 26666 One James River Plaza Richmond, VA 23261 l
W. Hartley l
Virginia Power Company l
5000 Dominion Blvd.
2SW Glenn Allen, VA 23060 l
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May 14,1993 l
ND3MNO:3454 l
Page 5 e
J. M. Riddle Halliburton NUS I
Foster Plaza 7 661 Anderson Drive Pittsburgh, PA 15220 Bill Wegner, Consultant 23 Woodlawn Terrace Fredricksburg, VA 22405 i
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Telephone (412) 393-6000 Nuclear Group P O Box 4 Shippmgport. PA 15077 4904 l
May 14,1993 ND3MNO:3454 Beaver Valley Power Station, Unit No.1 Docket No. 50-334, Licensee No. DPR-66 Special Reoort United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555
+
Gentlemen:
In accordance with Appendix A, Beaver Valley Technical Specification 4.4.5.5,
" Steam Generators", the following Special Report is submitted. This report documents the results of the Inservice Inspection of the steam generator tubes, performed during the Ninth Refueling Outage.
On May 2,1993, the inservice inspection of the tubing in steam generators RC-E-1A (S/G A), RC-E-1B (S/G B), and RC-E-1C (S/G C) was completed.
One hundred percent (100%) of all active steam generator tubes were scheduled for bobbin coil eddy current examination as part of the initial steam generator inspection scope of I
work. The examinations in the "B" steam generator were designated as those required to meet Technical Specification surveillance requirements.
The bobbin coil examination identified fifteen (15) " defective" tubes requiring removal from service per l
Technical Specification requirements. Although this number does not necessitate a C-3 l
categorization, and subsequent expansion of examination scope, the previously stated initial sample plan accommodated a one hundred percent (100%) examination of all active tubes.
In addition, specialized supplemental examinations [i.e. motorized rotating pancake coil (MRPC) and U-bend MRPC] were performed on distorted signal l
indications (DSIs) and on row I and 2 U-bends. In the "B" steam generator, an additional 182 tubes were removed from service based on supplemental examination and conservative Beaver Valley Power Station eddy current analysis guidelines.
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May 14,1993 ND3MNO:3454 Page 2 Greater than seventy percent (70%) of the indications requiring removal of tubes from service were identified at the hot leg tube support plate intersections. The probable defect mechanism for these tube degradation's is Outside Diameter Stress Corrosion Cracking (ODSCC). This is based on the metallurgical results from an examination of a tube that was removed during the Eighth Refueling Outage. All defective tubes have been plugged and Beaver Valley will continue with boric acid I
addition to the secondary plant water. The boric acid causes the tube-to-support plate crevices to become less basic and thereby reduces the propensity for ODSCC.
In addition to the above tube examinations,100% of the B&W cold leg plugs fabricated from inconel 600 were examined. The examination revealed crack-like indications in the plugs of heat #2848. All thirty-five (35) plugs of heat #2848 (20 in "B" steam generator, and 15 in "C" steam generator) were replaced. Additionally, one (1) plug from the "A" steam generator (heat #W592) was replaced because it was found hanging below its originally rolled position. All plugs of heat #W592 were re-rolled as a remedial action. Another plug (heat #7042) was replaced in the hot leg side of the "B" steam generator due to crack-like indications being observed during examination of 1
the plugs. One hundred percent of all plugs of heat #7042 were examined as a result of this indication. No other indications were observed. All replacement plugs were fabricated from Inconel 690 material.
The following table is provided as a summary of the Ninth Refueling Outage steam generator inspection results:
1 S/G A S/G B S/G C j
Tubes inspected this outage 2882 3086 3144 Tubes plugged this outage 221 197 150 Previously plugged 506 302 244 l
Total tubes plugged 727(21.5 %) 499(14.7 %) 394(11.6 %)
f B&W plugs replaced 1
21 15 (included in total above)
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May 14,1993 ND3MNO:3454 l
Page 3 l
The NSSS Vendor (Westinghouse) has analyzed for an increased plugging limit j
of 30 percent. This revised plugging limit will be implemented prior to returning to power from the Ninth Refueling Outage. The current limit is 20 percent in any single l
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Ak hka-L. R. Freeland General Manager
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ND3MNO:3454 Page 4
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i Mr. T. T. Martin, Regional Administrator United States Nuclear Regulatory Commission l
Region 1 475 Allendale Road L
King of Prussia, PA 19406 Mr. G. E. Edison, BVPS Licensing Project Manager i
United States nuclear Regulatory Commission Washington, DC 20555 Larry Rossbach, Nuclear Regulatory Commission, BVPS Senior Resident Inspector j
f J. A. Holtz, Ohio Edison i
76 S. Main Street i
Akron, OH 44308 l
Larry Beck Centerior Energy 6200 Oak Tree Blvd.
Independence, OH 44101-4661 l
INPO Records Center l
700 Galleria Parkway l
Atlanta, GA 30339-5957 l
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Mr. Robert Barkanic
[
Department of Environmental Resources
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P.O. Box 2063 16th Floor, Fulton Building l
Harrisburg, PA 17120 Director, Safety Evaluation & Control Virginia Electric & Power Co.
P.O. Box 26666 One James River Plaza l
Richmond, VA 23261 W. Hartley Virginia Power Company 5000 Dominion Blvd.
2SW Glenn Allen, VA 23060
l May 14,1993 i
ND3MNO:3454 Page 5 J. M. Riddle Halliburton NUS Foster Plaza 7 661 Anderson Drive Pittsburgh, PA 15220 Bill Wegner, Consultant 23 Woodlawn Terrace Fredricksburg, VA 22405 l
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