ML20211N222
| ML20211N222 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 10/09/1997 |
| From: | Langenbach J GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 6710-97-2450, NUDOCS 9710160061 | |
| Download: ML20211N222 (7) | |
Text
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l GPU f,uclear. Inc
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floute 441 south NUCLEAR Post Off to Box 480 Middletown. PA 17057 0480 October 9,1997 M 717 844ml 6710-97 2450 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 Gentlemen:
Subject:
Three hiite Island Nuclear Station, Unit 1 (Th11 1)
Docket No. 50-289 Operating License No. DPR 50 Additional Information to Support Technical Speci0 cation Change Request (TSCR) No. 268 - OTSG Inspection Criteria for 12R T,xaminations Attachment I to this letter provides additional information regarding TMI l Technical Specification Change Request (TSCR) No. 268 in response to a question from the NRC during a conference call on October 6,1997. This information is clarifying in nature and therefore does not afTect the safety evaluation justifying the proposed license amendment and does not change any of the conclusions supporting the no significant hazards consideration analysis provided in TSCR No. 268 Also enclosed as attachment 2 is the Certificate of Service for this request certifying service to the chief executives of the township and county in which the facility is located, as well as the designated official of the Commonwealth of Pennsylvania, Bureau of Radiation Protection.
Sincerely, 04t[tt
- ' wt4 [O 4t James W. Langenbac i Vice Presid nt and Director, TMI h CO!
j MRK Attachments: (1) Additional Information Regarding Technical Specification Change Request No. 268 1 L 0 C 7 (2) Certificate of Senice for Additional information Supporting Technical SpeciGeation Change Request No. 268 cc:
Administrator, NRC Region I TMl Senior NRC Resident inspector TMI-l Senior NRC Project Manager kl$l$ l$f,ll!llfllllfllll}
9710160061 971009 PDR ADOCK 05000289 p
NITACilMENT f Additional Information Regarding Technical Specification Change Request No. 268 l
Additional information Regarding
, TMI-l Technical Specification Change Request No. 268 NitC Guestion:
II' hat assurance is there that the ndumetric ID IGA that is allowed to remain in service will not leak ifsubjected topostulatedMSlJ1 accident conditions?
GpU Nuclear Response:
Technical Specification Change Request (TSCR) No. 268 requests that inside diameter (ID) volumetric Inter granular Attack (IGA) oflimited axial and circumferential extent be allowed to remain in service. The requested Technical Specification change does not permit leaving crack like indications in service. Over ten years of ECT results have confirmed that volumetric ID IGA is not expected to degrade further in the absence of reduced rifur species at cold plant conditions.
Furthermore, the absence of tube leakage during TMI l operating Cycle 11 is evidence that none of volumetric ID IGA indications left in service in TMI l steam generators is currently 100% through-wall.
During the Cycle 12 Refueling (12R) Outage, eddy current testing (ECT) examinations performed on all inservice tubes in both steam generators found approximately 997 ID indications. Seven (7) of'.he 997 ID indications were found to have circumferential morphology; three were in situ pressure tested to assess their structural integrity. All seven ID indications with circumferential morphology were plugged and none of these tubes remain in service for Cycle 12 operation.
Approximately 990 of the 997 ID indications were found to be volumetric ID IGA indications addressed by TSCR No. 268. Of the 990 ID IGA indications, approximately 884 indications -
(representing 368 tubes) met the axial and circumferential extent criteria permitted by TSCR No.
268 and therefore were left in service for Cycle 12 operation. Tubes that contained the balance of those indications were taken out of service.
During the 12R Outage, two of the most limiting ID IGA volumetric indications were selected for in situ pressure testing. One of these tubes. A107-120 had an ID IGA volumetric indication having a "large" axial extent equal to 0.27 inches and a circumferential extent equal to 0.25 inches. The axial extent was considered "large" because it exceeded the proposed 0.25 inch structural limit in accordance with TSCR No. 268. During the in situ pressure tests, these tubes experienced a pressure of 4400 psig,3 times the operating pressure differential in accordance with Regulatoiy Guide (RG) 1.121, with no measurable leakage. These tubes with volumetric ID IGA were subjected to membrane hoop stress that approached the material yield' strength. In the immediate vicinitu of the axial component of the flaw, local hoop stress exceeded the material yield strength becam of the stress intensification caused by the flaw that could possibly result in a local increase in damage extent of the axial features of the volumetric flaw.
The axial component of these IGA flaws did not indicate any flaw growth during the post in-situ pressure test ECT examination aller being exposed to these stresses. No increase in the axial damage extent occurred under near yield strength loading even for the indication that exceeded the structural limit.
' De minimum yield strength of TMI l steam generator tube material is 41 ksi.
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6710 97-2450 Page 2 of 2 Similarly,,1f the circumferential component of the volumetric ID IGA (the largest of which is 0.35 inches) had been exposed to stresses approaching or equaling the yield strength, similar non-leaking and non growing behavior (to that of the axial cc.., aent) would be expected even considering circumferential extent that approached the structural limit. All of the volumetric ID IGA remaining in service is less than the axial and circumferential limits.
All of the ID IGA remaining in service is well within the structural limits. None of the indications left in service are 100% through wall. Volumetric ID IGA of the larger extents as measured during the 12R Outage did not degrade further (based on the post in situ test ECT), nor did they leak when subjected to Regulatory Guide 1.121 stresses (stresses imposed by 3 times the operating differential pressure). Therefore, the volumetric ID IGA remaining in service for Cycle 12 operation is not expected to leak during normal power operation or under MSLil accident conditions due to its small size and inactive growth behavior, s
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t ATTArilM ENT II Certificate of Service for Additional information Regarding TMI-l Technical Specification Change Request No. 268
hiETROPOLITAN EDISON COMPANY JERSEY CENTRAL POWER & LIGilT COMPANY AND PENNSYLVANIA ELECTRIC COMPANY TilREE MILE ISLAND NUCLEAR STATION, UNIT 1 Operating License No. DPR-50 Docket No. 50-289 Additional Information Regarding Technical Specification Change Request No. 268 COMMONWEALTI-I OF PENNSYLVANI A
)
) SS:
COUNTY OF DAUPillN
)
This additional information is submitted in suppon of Licensee's request to change Appendix A to Operating License No. DPR 50 for Three Mile Island Nuclear Statiott, Unit 1. All statements contained in this submittal have been reviewed, and all such statements made and matters set forth therein are true and correct to the best of my knowledge.-
GPU NUCLEAR INC.
BY:
m il 4
e President and htor, TMI Sworn and Subscribed to before me this f4f dayof [tMVu;~.1997.
. $C2 a
J Debra S [I No Public hTcTAMM@ds?#ls FArber.Pemprarn Amven et tarm
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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION i
IN T11E MATTER OF DOCKET NO. 50-289 GPU NUCLEAR INC.
LICENSE NO. DPR-50 1
j CERTIFICATE OF SERVICE j
This is to cenify that a copy of the additional information regarding TMI-l Technical Specification Change Request No. 268 for Three Mile Island Nuclear Station Unit 1, has, on the date given below, been filed with executives of Londonderry Township, Dauphin County, l
Pennsylvania; Dauphin County, Pennsylvania; and the Pennsylvania Department of
[
Environmental Resources, Bureau of Radiation Protection, by deposit in the United States mail, l.
addressed as follows:
i i
Mr. Darryl Leliew, Chairman Ms. Sally S. Klein, Chairman j
Board of Supervisors of Board of County Commissioners Londonderry Township of Dauphin County i
R. D. #1, Geyers Church Road Dauphin County Courthouse Middletown, PA 17057 liarrisburg, PA 17120 i
i Director, Bureau of Radiation Protection l-PA Dept. of Environmental Resources Rachael Carson State Ollice Building P.O. Box 8469
.liarrisburg, PA 17105-8469 Att: Mr. Stan Maingi
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GPU NUCLEAR INC.
BY:
sn l
ce President and Diff: tor, TMl i
/6[9 fd DATE:
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