ML17265A417
| ML17265A417 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 09/16/1998 |
| From: | Mecredy R ROCHESTER GAS & ELECTRIC CORP. |
| To: | Vissing G NRC (Affiliation Not Assigned), NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-97-05, GL-97-5, TAC-MA0466, TAC-MA466, NUDOCS 9809290218 | |
| Download: ML17265A417 (8) | |
Text
CATEGORY 1 REGULA'I
.Y INFORMATION DISTRIBUTIOWYSTEM (RXDS)
ACCESSION NBR:9809290218 DOC.DATE: 98/09/16 NOTARIZED: YES FAClL:50-244 Robert Emmet Ginna Nuclear Plant, Unit 1, Rochester G
AUTH.NAME'-
AUTHOR AFFILIATION MECREDY,R.C.
Rochester Gas
& Electric Corp.
RECIP.NAME RECIPIENT AFFILIATION VXSSING,G.
DOCKET 05000244
SUBJECT:
Forwards response to NRC RAX re GL 97-05 response for RE Ginna Nuclear Power Plant.
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TITLE: GL 97 Steam Generator Tube Inspections Technicpxes NOTES:License Exp date in accordance 'with 10CFR2,2.109(9/19/72)
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canto ROCHESTER GAS ANDELECTRIC CORPORATION 89 EASTAVENLIE, ROCHESTER, N.V. 14649-0001 AREA CODE 716-546-2700 ROBERT C. MECREDY Vice President Nvdeor operations September 16, 1998 U.S. Nuclear Regulatory Commission Document Control Desk Attn:
Guy Vissing Project Directorate I-l Washington, D.C. 20555
Subject:
Response to Request for Additional Information (RAI)Related to Generic Letter 97-05 (TACNo. MA0466)
R. E. Ginna Nuclear Power Plant Docket No. 50-244 Ref. (1):
Letter from Guy S. Vissing (NRC) to Robert C. Mecredy (RG&E),
SUBJECT:
REQUEST FOR ADDITIONALINFORMATION(RAI)
RELATINGTO GENERIC LETTER 97-05 RESPONSE FOR THE R. E.
GINNANUCLEARPOWER PLANT (TAC No. MA0466 ), dated August 11, 1998
Dear Mr. Vissing:
By reference 1, the NRC staF requested additional information regarding the response to generic letter 97-05 for the R. E. Ginna Nuclear Power Plant. The attachment to this letter provides the requested information.
Very trul yours, Robert C. Mecredy Attachment Subscribed and sworn to before me on this Nth day ofSeptember, 1998 I'I Notary Public LORETTA MAR<'-IALLPARKER Notary Pubac m the '!ate of Ncw York MONROE COUNTY Comm>sston Expires Dec. 12, 19..
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Mr. Guy S. Vissing (Mail Stop 14B2)
Project Directorate I-1 Division ofReactor Projects - UII Once ofNuclear Regulatory Commission U. S. Nuclear Regulatory Commission Washington, D.C. 20555 Regional Administrator, Region I U. S. Nuclear Regulatory Commission 475 Allendale Road King ofPrussia, PA 19406 U.S. NRC Ginna Senior Resident Inspector
The response to GL 97-05 indicated that the licensee has qualified a technique to size the depth ofsmall volume manufacturing burnish marks (MBM).Itwas noted that the response did not address performing a reexamination ofpreservi ce eddy current inspection data to confirm the presence ofMBMindicationsidentifieddiiringinservice inspections.
Discuss whether itis the practice ofGinna Station t'o review preservice inspection data to confirm the presence ofMBM indications. Ifthisis not the practice employed by the licensee, discuss the qualification ofeddy current inspection techniques used duringinspections to adequately distinguish between MBM and other modes ofvolumetric tube degradation.
It is the practice at Ginna station to review Steam Generator baseline data to confirm the presence ofMBMindications. This information was previously provided to the NRR chemistry branch during the Ginna 1997 refueling outage Steam Generator inspection conference call. This MBM review is performed at multiple levels ofeddy current analysis, which willbe discussed along with Ginna inspection methodology and examination history.
The Ginna Babcock &Wilcox International (BWI)replacement steam generators had a ASME section XIbaseline examination performed prior to installation. This inspection included 100%
Bobbin coil examination tube end to tube end, 100% inlet and outlet bobbin profilometry, and MRPC inspections at selected locations to improve our knowledge base. Rochester Gas &
Electric thoroughly documented all detectable manufacturing imperfections. Based on a bobbin coil normalization ofsix (6) volts on the four (4) 0.026" 100% through the wall holes at optimum frequency (550 KHZ.), all MBMimperfections were recorded at a threshold of0.4 volts on the 140 KHZ. absolute.
A post installation preservice bobbin coil peripheral examination using the same baseline examination technique and normalization methodology was performed to assure no shipping or installation damage had occurred.
During the first inservice examination a 100% bobbin coil tube end to tube end examination with the same baseline examination technique and normalization methodology was performed, as well as MRPC on selected roll transitions, tight radius u-bends, and outer radius u-bends to further improve our knowledge base.
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Atechnique for detection and sizing ofMBM's was submitted by Rochester Gas &Electric to the EPRI NDE center for EPRI S/G Examination Guidelines Appendix H peer review prior to the first ISI examination. The technique was approved by the peer review group. The technique for MBMsizing gave Rochester Gas 8c Electric the ability to determine the manufacturing buffmark depth based on a manufacturing buffmark eddy current indication response.
Based on this qualification it was determined that an MBMwith a 5% through wall depth provided a 2.5 volt eddy current signal response from 140 KHZ. absolute. This qualification provides conservative sizing due to the fact that all MBM's are considered to have a 120'ircumferential extent. Based on information provided by the tubing manufacture and Ginna specific MRPC data, the majority ofMBM's detectable with eddy current contain circumferential extents ofat least 120', while many MBM's'have circumferential extents greater than 120'.. This provides a larger signal response from the 140 KHZ. absolute and a greater, more conservative, depth estimate.
Based on this background Ginna has employed a methodology to address MBMindications. The primary analysts utilize the Zetec Historical Management Software (HMS). This tool enables the analyst to look at all baseline indications in report form and to compare current ISI inspection data to baseline data. Ifthere is a change from the baseline then the change is addressed. Ifthere are new indications, the primary analyst addresses them at this time. In addition we have selected a 2.5 volt 140 KHZ. absolute response reporting criteria. The primary and secondary analysts report all MBMindications in excess ofthis threshold. The primary and secondary analysts also report all MBMindications with a differential mix response above the horizontal baseline. New indications, MBM's above the 2.5 volt threshold, and MBM's with a differential response above the baseline are mandatory indications for a resolution analyst to further review.
The resolution analyst performs a direct signal comparison utilizingthe Zetec Data Segment Recall Software (DSR). This comparison is performed on any new indications, any MBM indications in excess of2.5 volts, and any indications that have a differential mix response above the horizontal baseline. The signal response from the ISI inspection is then compared to the same signal response from the baseline examination. The specific eddy current signal response is compared for any changes.
Changes are considered to have taken place when an increase in signal voltage, an increase in signal length, or a change in eddy current phase rotation towards the flaw plane in a logical phase rotation between the multiple frequencies has occurred. Ifno eddy current signal change is observed the resolution analyst records the indication as dispositioned by preservice. Ifthe resolution analyst observes a change in eddy current signal response from baseline, the resolution analyst labels the signal as changed from preservice and the indication is further examined with the MRPC+point delta coil. The indication could than be dispositioned as a volumetric indication, or labeled as degraded.
The Ginna Steam Generator tubing MBMeddy current analysis process accounts for the detection ofnew indications, and the possibility ofinservice changes ofMBMindications.
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