ML20206H289

Forwards Exemption from Requirements of 10CFR50.60, Acceptance Criteria for Fracture Prevention Measures for Lightwater Nuclear Power Reactors for Normal Operation, for Wcgs.Exemption Related to Application

ML20206H289
Person / Time
Site:	Wolf Creek
Issue date:	04/30/1999
From:	Thomas K NRC (Affiliation Not Assigned)
To:	Maynard O WOLF CREEK NUCLEAR OPERATING CORP.
Shared Package
ML20206H291	List: ML20206H289 ML20206H335
References
TAC-MA4955, NUDOCS 9905110149
Download: ML20206H289 (2)

Text

g April 30, 1999 Mr. Otto L. M:yntrd 4-PrIsident cnd Ch%f Ex cutiva Officer

. Wolf Creek Nuclear Operating Corporation 4 Post Office Box 411 Burlington, Kansas 66839

SUBJECT:

' ISSUANCE OF EXEMPTION FROM THE REQUIREMENTS OF 10 CFR 50.60 -

' WOLF CREEK GENERATING STATION, UNIT 1 (TAC NO. MA4955)

Dear Mr. Maynard:

The Commission has issued the' enclosed Exemption from certain requirements of 10 CFR 50.60, " Acceptance Criteria for Fracture Prevention Measures for Lightwater Nuclear Power Reactors for Normal Operation," for the Wolf Creek Generating Station (WCGS). The exemption is related to your application dated December 29,1998. Section 50.60 requires all

' power reactors to meet the fracture toughness and material surveillance program requirements for the reactor coolant pressure boundary set forth in Appendices G and H to 10 CFR Part 50.

The exsmption would allow WCNOC to apply American Society for Mechanical Engineers (ASME) Code Case N-514 for determining the WCGS cold overpressurization mitigation system (COMS) pressure setpoint.

Based upon the information provided, there is reasonable assurance that, based on the conservatism which is explicitly in Appendix G methodology, permitting the COMS setpoint to be established such that the vessel pressure would not exceed 110 percent of the limit defined by the P-T limit curves provides an adequate margin of safety against brittle failure of the reactor vessel. The staff further agrees that limiting the potential for inadvertent COMS  !

-actuation may improve plant safety, i A copy of the Exemption is encibsed. The Exemption is being forwarded to the Office of the Federal Register for publication.

$ kN Ek2 P ra ig 'al Signed By Kristine M.IThomas, Project Manager, Section 2

• For previous concurrences Project Directorate IV & Decommissioning i see attached ORC ' Division of Licensing Project Management l Office of Nuclear Reactor Regulation i

. Docket No. 50-482 DISTRIBUTION: -

Docket m SRichards OGC

Enclosure:

Exemption PUBLIC SDembek ACRS PDIV Reading KThomas DLange, EDO cc w/ encl: See next page SCollins/RZimmerman EPeyton KBrockman, RIV

• For previous concurrences . BSheron , GHill (2) LYandell, RIV see attached ORC JZwolinski/SBlack MBoyle WBateman DOCUMENT NAME: WCA4955A.WPD OFC PDIV/PM PDIV/LA PDIV/SC , NRR:EMCB* OGC*

f NAME Kfbas t:/edoW SDembek WBateman STurk DATE 4/8/99 462il/99 4flf /9 3/ 30 /99 4/16 /99 0\

OFC PDIV PM/

, v NAME SRichards 3Ewolin(ski 4 3gQ

^

DATE 4/M/99 4/9/99' OFFICIAL RECORD COPY j

%g

[p# 4 Al UNITED STATES j

NUCLEAR REGULATORY COMMISSION e

o f WASHINGTON, D.C. 20565 4101

%- # April 30, 1999 l

Mr. Otto L. Maynard l President and Chief Executive Officer J

. Wolf Creek Nuclear Operating Corporation Post Office Box 411 Burlington, Kansas 66839

SUBJECT:

- ISSUANCE OF EXEMPTION FROM THE REQUIREMENTS OF 10 CFR 50.60 -  ;

WOLF CREEK GENERATING STATION, UNIT 1 (TAC NO. MA4955)

]

Dear Mr. Maynard:

The Commission has issued the enclosed Exemption from certain requirements of 10 CFR 50.60, " Acceptance Criteria for Fracture Prevention Measures for Lightwater Nuclear Power Reactors for Normal Operation," for the Wolf Creek Generating Station (WCGS). The exemption is related to your application dated December 29,1998. Section 50.60 requires all power reactors to meet the fracture toughness and material surveillance program requirements l for the reactor coolant pressure boundary set forth in Appendices G and H to 10 CFR Part 50. l The exemption would allow WCNOC to apply American Society for Mechanical Engineers (ASME) Code Case N-514 for determining the WCGS cold overpressurization mitigation system (COMS) pressure setpoint.

Based upon the information provided, there is reasonable assurance that, based on the conservatism which is explicitly in Appendix G methodology, permitting the COMS setpoint to be established such that the vessel pressure would not exceed 110 percent of the limit defined by the P-T limit curves provides an adequate margin of safety against brittle failure of the reactor vessel. The staff further agrees that limiting the potential for inadvertent COMS actuation may improve plant safety.

A copy of the Exemption is enclosed. The Exemption is being forwarded to the Office of the Federal Register for publication.

Sincerely,

, IUTW Kristine M. Thomas, Project Manager, Section 2 Project Directorate IV & Decommissioning Division of Licensing Project Management Office of Nuclear Rsactor Regulation Docket No. 50-482

Enclosure:

Exemption cc w/ encl: See next page