ML20128N343

Forwards Safety Evaluation Re Evaluation of Flaw Indication Found During Reactor Pressure Vessel Insps at Plant

ML20128N343
Person / Time
Site:	Vermont Yankee
Issue date:	10/11/1996
From:	Craig Harbuck NRC (Affiliation Not Assigned)
To:	Reid D VERMONT YANKEE NUCLEAR POWER CORP.
Shared Package
ML20128N346	List: ML20128N343 ML20128N353
References
TAC-M96670, NUDOCS 9610160360
Download: ML20128N343 (3)

Text

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, October 11, 1996 Mr. Donald A. Reid Vice President, Operations l

Vermont Yankee Nuclear Power Corporation '

Ferry Road Brattleboro, Vermont

SUBJECT:

EVALUATION OF FLAW INDICATION FOUND DURING REACTOR PRESSURE VESSEL INSPECTIONS AT VERMONT. YANKEE NUCLEAR POWER STATION (TAC NO.

M96670)

Dear Mr. Reid:

By letter dated October 9, 1996, as supplemented on October 11, 1996, Vermont Yankee Nuclear Power Corporation (the licensee) submitted a flaw evaluation report for NRC review and approval. The report contained the licensee's evaluation of a flaw > indication in the reactor pressure vessel (RPV) that exceeded the allowable flaw sizes in IWB-3500 of the American Society of Mechanical Engineers (ASME) Code, Section XI. t Ultrasonic examinations (UT) of the RPV were performed in accordance with the requirements of the ASME Code, '

Section XI, 1986 Edition. The UT examinations resulted in one flaw, out of a l r total of seven, that was not acceptable by IWB-3500 acceptance standards.

The flaw is located in Plate 1-15, below the circumferential weld that joins '

Plates 1-12 and 1-15. Plate 1-15 extends into the beltline region; however, the flaw is outside of the core region and is circumferential in orientation.

Since the flaw is located near the circumferential weld, it was evaluated by

. assuming that its location is within the weld metal as well as within the plate. The flaw evaluation was performed using the methodology in Appendix A of Section XI of the ASME Code, and met the criteria in IWB-3600.

Since the licensee's flaw evaluation meets the ASME Code criteria in IWB-3600, Vermont Yankee can be operated without repair to the subject plate. The NRC staff's evaluation is enclosed.

Sincerely, Original Signed BV C. Craig Harbuck, Acting Senior Project Manager Project Directorate I-1 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation

Enclosure:

As stated Docket No. 50-271 4

cc: See next page DISTRIBUTION:

h Docket File JZwolinski OGC

, PUBLIC SBajwa ACRS \

PDI-1 Reading Slittle LDoerflein, RGN-I SVarga CHacbuck Alee l DOCUMENT NAME: VY96670.LTR *See previous concurrences To receive a copy of this document, indir .te in the box: "C" - Copy without attachment / enclosure "E" - Copy with attachment / enclosure "N" - No copy 0FFICE PM: POI 1 lE LA: POI 1 l D: POI 1 /g]h l l l NAME CNartiuck' BCLayton* SBajwe /# 7 DATE 10/11/M 10/11/ % 10/ p /% 10/ /% 10/ /%

Official Record Copy 160080 NRC FILE CENTER COPY

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pw ym t UNITED STATES a E NUCLEAR REGUI.ATOFlY COMMISSION f WASHINGTON, D.C. 20655-0001 October 11, 1996 Mr. Donald A. Reid Vice President, Operations  !

i Vermont Yankee Nuclear Power Corporation Ferry Road Brattleboro, Vermont

SUBJECT:

EVALUATION OF FLAW INDICATION FOUND DURING REACTOR PRESSURE VESSEL INSPECTIONS AT VERMONT YANKEE NUCLEAR POWER STATION (TAC NO.

M96670)

Dear Mr. Reid:

By letto dated October 9, 1996, as supplemented on October 11, 1996, Vermont Yankee Nuclear Power Corporation (the licensee) submitted a flaw evaltation report for NRC review and approval. The report contained the licensee's  ;

evaluation of a flaw indication in the reactor pressure vessel (RPV) that exceeded the allawable flaw sizes in IWB-3500 of the American Society of Mechanical Engineers (ASME) Code, Section XI. Ultrasonic examinations (UT) of j the RPV were performed in accordance with the requirements of the ASME Code, Section XI, 1986 Edition. The UT examinations resulted in one flaw, out of a total of seven, that was not acceptable by IWB-3500 acceptance standards.

The flaw is located in Plate 1-15, below the circumferential weld that joins Plates 1-12 and 1-15. Plate 1-15 extends into the beltline region; however, the flaw is outside of the core region and is circumferential in orientation.

Since the flaw is located near the circumferential weld, it was evaluated by assuming that its location is within the weld metal as well as within the plate. The flaw evaluation was performed using the methodoloc. .n Appendix A of Section XI of the ASME Code, and met the criteria in IWB-3600.

Since the licensee's flaw evaluation meets the ASME Code criteria in IWB-3600, Vermont Yankee can be operated without repair to the subject plate. The NRC staff's evaluation is enclosed.

Sincerely,

[  % &

C. Craig Harbuck, Acting Senior Project Manager Project Directorate I-I Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation

Enclosure:

As stated Docket No. 50-271 cc: See next page

. l l

D. Reid Vermont Yankee Nuclear Power Station j Vermont Yankee Nuclear Power l

! Corporation  !

cc:

Regional Administrator, Region I G. Dana Bisbee, Esq. I U. S. Nuclear Regulatory Commission Deputy Attorney General j l

475 Allendale Road 33 Capitol Street King of Prussia, PA 19406 Concord, NH 03301-6937 R. K. Gad, III Resident Inspector Ropes & Gray i Vermont Yankee Nuclear Power Station One International Place U.S. Nuclear Regulatory Commission l

Boston, MA 02110-2624 P.O. Box 176 Vernon, VT 05354 l Mr. Richard P. Sedano, Commissioner Vermont Department of Public Service Chief, Safety Unit 1

120 State Street, 3rd Floor Office of the Attorney General Montpelier, VT 05602 One Ashburton Place, 19th Floor Boston, MA 02108 Public Service Board State of Vermont Mr. David Rodham, Director 120 State Street ATTN: James Muckerheide Montpelier, VT 05602 Massachusetts Civil Defense Agency l 400 Worcester Rd. '

Chairman, Board of Selectmen P.O. Box 1496 Town of Vernon Framingham, MA 01701-0317 P.O. Box 116 Vernon, VT 05354-0116 Mr. Raymond N. McCandless Vermont Division of Occupational Mr. Jay Thayer, Vice President and Radiological Health Vermont Yankee Nuclear Power Administration Building Corporation Montpelier, VT 05602 Ferry Road Brattleboro, VT 05301 Mr. J. J. Duffy Licensing Engineer Mr. Robert J. Wanczyk, Plant Manager Vermont Yankee Nuclear Power Vermont Yankee Nuclear Power Station Corporation P.O. Box 157, Governor Hunt Road 580 Main Street Vernon, VT 05354 Bolton, MA 01740-1398 I

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