ML20094D843

Submits Addl Info for Request for Relief from ASME Code for Replacement of Code Class 3 Piping

ML20094D843
Person / Time
Site:	Sequoyah
Issue date:	11/03/1995
From:	Shell R TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9511060277
Download: ML20094D843 (2)

Text

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1. b IM Tennostee Valley Aufnonly. Post Omce Box 2000. Soddy Dasy Tennessee 37373 November 3,1995 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Gentlemen:

In the Matter of ) Docket No. 50-328 Tennassee Valley Authority )

SEQUOYAH NUCLEAR PLANT (SON)- ADDITIONAL INFORMATION FOR REQUEST FOR RELIEF FROM AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) CODE FOR REPLACEMENT OF CODE CLASS 3 PIPING

Reference:

TVA letter to NRC dated August 7,1995,"Saquoyah Nuclear Plant (SON)

- Request for Relief From American Society of Mechanical Engineers (ASME) Code for Replacement of ASME Code Class 3 Piping" Conversations with NRC staff have indicated that there is a need to docket the reason TVA requested temporary relief from the ASME code in the above reference. As discussed in the above referenced letter, a pin-hole leak has occurred on the essential raw cooling water (ERCW) discharge pipe of the 2A-1 diesel generator (D/G) heat exchanger. TVA evaluated the operability impact on the D/G and ERCW system and determined that they will continue to perform their design functions. Based upon the above information, TVA stated that it would replace the affected section of pipe during the next scheduled 2A-A D/G maintenance outage (scheduled for February 1996). The repair is estimated to take a substantial portion of the 72-hour allowed outage time for a D/G. The reason TVA elected to not repair the leak at the time of discovery is that, based upon the safety significance of the leak, the increased unavailability of the D/G was judged to not be in the best interest of nuclear safety.

TVA realizes that this position is not fully in accordance with Generic Letter (GL) 90-05. GL 90-05 defines " impracticality" as a Code Class 3 piping flaw that cannot be isolated for completing a code repair within the time period permitted by the limiting condition for operation. However, TVA believes that safety significance should also be evaluated in determining impracticality.

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. :.s U.S. Nuclear Regulatory Commission Page 2 November 3,1995

'Please direct questions concerning this issue to D. V. Goodin at (423) 843-7734.

Sincerely, he .

R. H. Shell: < $

Manager SON Site Licensing -

cc: Mr. D. E. LaBarge, Project Manager l

Nuclear Regulatory Commission One White Flint, North  !

11555 Rockville Pike ,

Rockville, Maryland 20852-2739 i

. NRC Resident inspector i Sequoyah Nuclear Plant  ;

2600 Igou Ferry Road ,

Soddy Daisy, Tennessee 37379-3624 l Regional Administrator f U.S. Nuclear Regulatory Commission i Region 11 101 Marietta Street, NW, Suite 2900

' Atlanta, Georgia 30323-2711 1

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