ML20207L594

Informs That Staff Accepts Util 981210 Requested Approval for Use of ASME Code,Section III Code Case N-611, Use of Stress Limits as Alternative to Pressure Limits,Section III, Div 1,Subsection NC/ND-3500, for Certain Valve Components

ML20207L594
Person / Time
Site:	Wolf Creek
Issue date:	03/04/1999
From:	Thomas K NRC (Affiliation Not Assigned)
To:	Maynard O WOLF CREEK NUCLEAR OPERATING CORP.
References
RTR-REGGD-01.084, RTR-REGGD-1.084 GL-96-06, GL-96-6, TAC-MA4428, NUDOCS 9903180193
Download: ML20207L594 (3)

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p8 March 4, 1999 Mr. Otto L. Maynard President and Chief Executive Officer Wolf Creek Nuclear Operating Corporation ,

Post Office Box 411 i Burlington, Kansas 66839 l

SUBJECT:

REQUEST TO ALLOW USE OF ASME CODE CASE N-611 AT WOLF CREEK f GENERATING STATION FOR EVALUATION OF GENERIC LETTER 96-06.  !

" ASSURANCE OF EQUIPMENT OPERABILITY AND CONTAINMENT INTEGRITY DURING DESIGN-BASIS CONDITIONS" (TAC NO. MA4428)

Dear Mr. Maynard:

) By letter dated December 10,1998, Wolf Creek Nuclear Operating Corporation requested i l approval for use of the American Society of Mechanical Engineers (ASME) Boiler and Pressure l Vessel Code, Section ill Code Case N-611, "Use of Stress Limits as an Alternative to Pressure Limits, Section 111, Division 1, Subsection NC/ND-3500," for certain valve components at the Wolf Creek Generating Station.

l The request is limited to use of Code Case N-611 for resolution of issues relating to NRC

! Generic Letter 96-06, " Assurance of Equipment Operability and Containment Integrity During Design-Basis Accident Conditions." Code Case N-611 has been approved by the ASME Board on Nuclear Codes and Standards by Letter Ballot 695 on July 30,1998, but has not yet been incorporated into NRC Regulatory Guide 1.84, " Design and Fabrication Code Case i Applicability, Section Ill, Division 1," for general use.

Generic Letter (GL) 96-06 provides, in part, that an evaluation be performed of isolated sections of piping containing trapped fluid which could expand when heated during licensing basis  ;

events causing the buildup of excessive internal pressure (i.e., thermal pressurization). For the  ;

applicable conditions, you indicated that you performed stress analyses and found that the l Code-allowable stress limits are not exceeded. However, for ASME Class 2 and 3 valves, i Subsection NC/ND-3521(b) and Table NC/ND-3521-1 specify a factored pressure limit, Pmax, I in addition to the identified stress limits. Your analyses showed that, even though the stress limits are met, Pmax could be exceeded for the associated valves for the required postulated conditions. Use of Code Case N-611 would allow Pmax to be exceeded provided the stress l limits of Table NC/ND-3521-1 are met. As justification for this request, you stated that for the '

! valves evaluated to address the GL 96-06 thermal pressurization issue, functionality (i.e., the ability to change position) is not required once the valves move to their closed position, i O

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PDR ADOCK 05000482 P pon

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. Mr. Otto L. Maynard March 4, 1999 I

i The staff has completed its review of your request to use Code Case N-611 in the evaluation of i the applicable ASME Class 2 and 3 valves at Wolf Creek affected by the GL 96-06 thennal i pressurization loads. The staff finds the requested application of Code Case N-611 to be  :

acceptable, since the associated valves are not required to be functional following the  !

postulated thermal pressurization events, and since meeting the required stress limits assures the pressure boundary integrity of the valves. This approvalis for this plant specific application i only.

If you have any questions, please contact me at (301) 415-1362, '

Sincerely, f

Kristine M. Thomas, Project Manager Project Directorate IV-2 Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-482 - . DISTRIBUTION:

J Docket File.  !

cc: See next page PUBLIC PDIV-2 Reading i JZwolinski  ;

WBateman  ;

KThomas i EPeyton l ACRS OGC K M kMb KBrockman, Region IV LYandell, Region IV <

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coreec} e l DOCUMENT NAME: WCCCN612 M OFC PDIV-2/PM PDIV-2/LA EMEB C NAME KThas KManoly N ]

DATE 3 /Lj /99 3 /cL/99 3/ 3 /99 <

OFFICIAL RECORD COPY i

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Mr. Otto L. Maynard March 4, 1999 l

i cc:  !

Jay Silberg, Esq. Chief Operating Officer Shaw, Pittman, Potts & Trowbridge Wolf Creek Nuclear Operating Corporation '

2300 N Street, NW P. O. Box 411  !

Washington, D.C.' 20037- ' Burlington, Kansas 66839 j

i Regional Administrator, Region IV Supervisor Licensing U.S. Nuclear Regulatory Commission ' l Wolf Creek Nuclear Operating Corporation  :

611 Ryan Plaza Drive, Suite 1000 P.O. Box 411 i Arlington, Texas 76011 . Burlington, Kansas 66839 Senior Resident inspector U.S. Nuclear Regulatory Commission U.S. Nuclear Regulatory Commission Resident inspectors Office l

P. O. Box 311 8201 NRC Road i Burlington, Kansas 66839 ' Steedman, Missouri 65077-1032 l

Chief Engineer i Utilities Division Kansas Corporation Commission J

.1500 SW Arrowhead Road Topeka, Kansas 66604-4027 '

l Office of the Governor l State of Kansas ,

Topeka, Kansas 66612 '

Attorney General Judicial Center 301 S.W.10th 2nd Floor i Topeka, Kansas 66612 .

County Clerk i Coffey County Courthouse  !

Burlington, Kansas 66839

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Vick L. Cooper, Chief Radiation Control Program '

Kansas Department of Health and Environment Bureau of Air and Radiation Forbes Field Building 283 Topeka, Kansas 66620 d

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