ML20056A954

Provides Final Response to NUREG-0737,Item II.D.1, Performance Testing of Safety Relief Valves. Util Will Change Seal Configuration for Existing Valves to Seal on Steam Medium & Install Continuous Drain for Loop Piping

ML20056A954
Person / Time
Site:	Mcguire, McGuire
Issue date:	08/01/1990
From:	Tucker H DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-2.D.1, TASK-TM TAC-76433, TAC-76434, NUDOCS 9008100248
Download: ML20056A954 (2)

Text

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• l (TN13?3 4531 DUKE POWER August 1, 1990 j j

U. S. Nuclear Regulatory Commission ,

ATTN: Document Control Desk  ;

Washington, D.C. 20555  !

Subject:

McGuire Nuclear Station, Units 1 and 2 Docket Nos. 50-369 and 50-370  ;

NUREG-0737 Item II.D.1, Performance Testing of Relief and Safety Valves NRC Review / Technical Evaluation Report -

Final Response (TACS 76433 and 76434)

Gentlement My letter of March 19, 1990 concerning deficiencies noted in the NRC's Technical Evaluation Report (TER) of the McGuire Nuclear Station response to NUREG-0737 Item II.D.1, Performance Testing of Relief and Safety Valves",

discussed an error that had been identified in the existing thermal hydraulic analysis (SLUGGER computer program) which invalidated the existing structural calculation results for the piping downstream of the pressurizer safety valves. Duke had reviewed the impact of the load changes due to this error on the structural analysis for the system and found that t'io system remained operable but was not in full compliance with the ASME Code, and Duke was reviewing reanalysis / field modification alternatives to bring the  ;

system within ASME Code compliance. These alternatives involved either "

modifying existing pressurizer code safety valves or purchasing new valves that will seal with a steam medium. This review was being performed to permit final resolution of NUREG-0737 Item II.D.1 by eliminating the transient load of the current water inventory that provides the water seals for the existing valves. An assessment of the result of this review and a schedule for performing and implementing this work in accordance with ASME requirements was to be included in a response (by August 1, 1990) addressing the results of combining seismic with the original analysis results (i.e.,

the Items 7 and 8b TER requested additional information).

Duke has determined that the most safe, efficient and cost effective alternative is to change the seal configuration for the existing valves to seal on a steam medium and installing a continuous drain for the existing loop piping. A modification request is underway to perform this work. Unit 2 valves and piping will be modified during the End of Cycle (EOC) 7 refueling outage currently scheduled to begin November 15, 1991, and the Unit i valves and piping will be modified d' iring the EOC8 refueling outage currently scheduled to begin October 12, 199L These schedules are appropriate considering equipment lead times and unit availability to obtain required surveillance information.

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U.-S. Nuclear-Regultttry Commiccion:

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e This response, reflecting the completion of the thermal hydhaulic and structural reanalysis and addressing the Items 7 and 8b additional

+ information requests, completes our response to NUREG-0737 Item II.D.1. The system .will be in ASME code compliance upon completion of the above .

discussed actions. Should there.be any questions concerning this j response / schedule or if further information is desired regarding the- i resolution of this issue, contact Bruce Nardoci at-(704) 373-7432. l Very.truly.yours, l

c ./ <4M  %, .

Hal'B. Tucker' '

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L T xc Mr. S.:D. Ebneter U. S.' Nuclear Regulatory Commission L .!

Region II t

>101 Marietta St., NW., Suite 2900 l Atlanta, Georgia 30323 ] l Mr. D. S.. Hood, Project Manager i Division of Licensing-Office of Nuclear Regulatory Commission.

Washington, D.C. 20555 u Mr. P. K. VanDoorn l L NRC Resident Inspector  !

McGuire Nuclear Station  ;

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