ML20076M515
| ML20076M515 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 11/02/1994 |
| From: | Shell R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9411070399 | |
| Download: ML20076M515 (2) | |
Text
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w m vay wm mmue e xm cu, nay wneme um November 2,1994 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Gentlemen:
In the Matter of
)
Docket Nos. 50-327 Tennessee Valley Authority
)
50-328 SEQUOYAH NUCLEAR PLANT (SON) - COMMITMENT STATUS FOR THE RESOLUTION OF THE FAULT CURRENT PROBLEM ON THE 6.9-KILOVOLT (kV)
UNIT BOARD LOAD BREAKERS (TAC NO. 00420B3)
Reference:
TVA letter to NRC dated March 24,1993, "Sequoyah Nuclear Plant 1
(SON) - Extension of Commitments Associated With Fault Current Problem for the 6.9-Kilovolt (kV) Unit Board Load Breakers (TAC No. 00420B3)"
TVA has completed the modifications and procedure revisions to implement the alignment of the 6.9-kV unit boards to the common station service transformers (CSSTs) as the normal unit power supply as last discussed in the above reference. The Unit 2 power supply is currently aligned to ;he CSST. Site procedures no longer have steps to switch the unit power supply to the unit station service transformers; thereby, assuring that the desired alignment is maintained during start-up and normal operations. The only remaining action is the switching involved in the alignment of the CSST supply for Unit 1.
For Unit 1, the alignment will be accomplished by procedure upon the next occasion that requires the unit turbine generator to be taken off-line. The reason for not performing the new alignment while Unit 1 remains online is to minimize the potential for inadvertent unit trips and unnecessary challenges to safety i
systems that could occur as a result of the voltage disturbances associated with the transfer of power supplies during power operation. Taking Unit 1 off-line for j
the sole purpose of accomplishing this alignment could also challenge safety j
systems. Thus, the preferred option is to perform the alignment at the next l
occasion requiring the turbine generator to be taken off-line. Since the revised procedures ensure the new CSST alignment for both units, TVA considers the commitments associated with this issue to be complete.
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DR ADOCK 05000327
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< U.S. Nuclear Regulatory Commission Page 2 November 2,1994 Please direct questions concerning this issue to Keith Weller at (615) 843-7527.
Sincerely, i k-R. H. Shell Manager SON Site Licensing cc: Mr. D. E. LaBarge, Project Manager Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852-2739 NRC Resident inspector Sequoyah Nuclear Plant
-2600 Igou Ferry Road Soddy-Daisy, Tennessee 37379-3624 Regional Administrator U.S. Nuclear Regulatory Commission Region 11 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323-2711
.