ML20057B352

Advises NRC of Rev to Commitment Made in Licensees Response to NRC Bulletin 88-008, Thermal Stresses in Piping Connected to Rcs

ML20057B352
Person / Time
Site:	Wolf Creek
Issue date:	09/17/1993
From:	Carns N WOLF CREEK NUCLEAR OPERATING CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
IEB-88-008, IEB-88-8, WM-93-0113, WM-93-113, NUDOCS 9309210228
Download: ML20057B352 (2)

Text

_ _ -

7 >

F e s WELF CREEK ' NUCLEAR OPERATING CORPORATION Nmt S "Buzi Carns Presujet and Chmt Leutvo Of%rr r Seotember 17, 1993 {

hd 93-0113 i

U. S. Huclear Pegulatory Commission i ATTH: Document Control Desk Mail Station P1-137  :

Washington, T 2. 20555

Reference:

Letter WM 88-0246, dated September 28, 1988, from B. D. Withers, WCHOC, to MRC s u bject: D'ocket No. 50-482: Revision to HRC Commitment Made in WCHOC's Response to NRC Bulletin 88-08 Gentlemen:

?

The purpose of this letter is to advise the URC of a revision to a commitment made in the Reference. The Reference responded to NRC Bulletin 88-08,

" Thermal Stresses in Piping Connected to Reactor Coolant- Systems." In response to MRC Bulletin 88-08, Wolf Creek Nuclear Operating Corporation (WCHOC) determined that the Pressurizer Auxiliary Spray Line (BB-081-BCA-2")

met the criteria put forth in the bulletin. This line has sufficient driving pressure head and temperature differential across the single normal closed 1 solation valve (BGHV8145) to be a potential candidate for developing a thermally stratified layer in the line downstream of valve - BGHV8145 due to leakage past the valve. Therefore, a commitment was made to leak test valve BGHV8145 on a refueling outage basis with the frequency of the leak testing being evaluated depending on the results of previous testing experience.

In July 6992, an analysis was conducted by an independent engineering company.

This an" lysis was conducted to determine if leakage through valve BGHV8145 could b. detected by monitoring pipe temperatures on the Pressurizer Auxiliary '

I Spray nine, rather than leak testing the valve during each refueling outage.

l This analysis concluded that the Pressurizer- Auxiliary Spray Line is. t susceptible to therrnal stratification induced fatigue at both the inlet and ,

outlet ends if leakage in the range of 0.01 to 1.0 gallons per minute (gpm) occurs through valve BGHV8145. By monitoring pipe temperatures at selected  ;

locations along the pipe, leakage equal to or greater than 0. 01 gpm can be detected. ,

On the basis of the results of the analysis, a plant modification requesti was issued to locate and install temperature monitoring instrumentation on the-Pressurizer Auxiliary Spray Line. This instrumentation was installed during 1 the sixth refueling outage. Leakage rates will be verified periodically. ,

j through the use of the thermocouples to determine if valve BGHV8145 requires l rework.  ;

l O f P.O. Box 411/ Burbngton, .KS f4839 / Phone- (316) 364 8831 bl 9309210228 930927 ^" ""*' ### "" mcm gDR ADOCK 05000482 B@I ,,

. PDR JQ _ _ _ _

4.

1. l l

WM 93-0113 Pa'ge 2 of ?

l Therefore, since monitoring pipe te.mpe r a tu r e s at selected locations along the pipe can detect leakage equal to or greater than 0.01 gpm, which is as effective as the current monitoring program, the revision to the commitment does not involve a r educti on from the original commitment. Also, in a letter dated November 1, 1991, from Mr. William D. Reckley, NRC, to Mr. Bart D.  !

Wi t h e r es , WCliot, the 11PC provided acceptable actions which can be taken in a

responco to NRC Eulletin 08-08. This letter stated that the installation of  ;

temperature monitoring instrumentation for detection of piping thermal cycling due to valve leakage is considerod to be an acceptable action by the NRC, which is consistent with the actions taken by WCNOC with the installation of the temporature monitoring instrumentation on the Pressurizer Auxiliary Spray Line. ,

l If you have any questions concerning this matter, please contact me at (316) 364-A031, ext"nsion 4000, or Mr. Kevin J. Moles at extension 4565. ,

very truly yours, p -

/ l Neil S. Carns President and Chief Executive Officer I

flSC/jad ec: W. D. Johnson (NRC)

J. L. Milhoan (NRC) ,

G A. Pick (NPC)

W. D. Peckley (NRC) l I

i l i

j l

j l

1 1

l 5

I

- - - , -- -