ML20207R292
| ML20207R292 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 03/12/1987 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | Ebneter S NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8703170072 | |
| Download: ML20207R292 (3) | |
Text
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.f TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNESSEE 37401 4
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l SN 157B Lookout Place N.,
N 121987
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U.S. Nuclear Regulatory Comunission l
Attn: Document Control Desk.
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,.g Office of Nuclear Reactor Regulation 1
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Washington, D.C'.
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Attention:
Nr. Stewart Ebneter In the Matter'of'.,
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Docket Nos. 50-327 Tennessue Valley Authority
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50-328 SEQUOYAH NUCLEnh PLANT - DIESEL GENERATOR LOADING SEQUENCES NRC requested information regarding the Sequoyah diesel generator loading i
t' sequence analyses during a meeting between TVA and NRC on January 21, 1987.
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TVA evaluated three diesel generator loading sequences:
loss of offsite power, loss of offsite power coincident with safety injection and Phase A f,j 1 cor.tainment isolation, and loss of offsite power coincident with safety
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it.jection and Phase B containment ' isolation. Plant modifications required to 1
ij a:eet these sequences are being implemented before restart of the respective
. Units.
Pfesently, the'Sequoyah Final Safety Analysis Report (FSAR) identifies two additional diesel generator loading sequences in addition to those listed l
above:
loss of offsite power with a delayed safety injection and safety injection with a deleyed' loss of offsite power. TVA is not evaluating these sequences because the delayed loss of offsite power and safety injection cases da ncit significantly contribute to the probability of core melt. TVA will revise the FSAR to Identify that only the coincident diesel generator loading,
' sequences'are design basis events. This revision is scheduled for the 1988 j
y annudi update.
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i The current,TVA pocition on design basis diesel generator loading sequences is consistont with NRC Power Systems Branch review reminder No.11.
NRC has also j
reviewe& the loss of offsite power following safety injection reset and l /
deterrtimd that TVA had adoquate procedures to recover from such an event.
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NRC's review was documented in sections 6.3.3 and 7.3.2 of their safety v
evaluatt.in report. -
The enclosure to this letter lists the conunitments made in this letter.
j Very truly yours, TENNESSEE VALLEY AUTHORITY
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R.
idley, D rector Nuclear Safet and Licensing i
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Enclosure i
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i U.S. Nuclear Regulatory Consalssion
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Mr. J. J. Holonich Sequoyah Project Manager U.S. Nuclear Regulatory Commission 7920 Norfolk Avenue Bethesda, Maryland 20814 Mr. G. G. Zech, Director TVA Projects U.S. Nuclear Regulatory Commission Region 1; 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 m
Sequoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379 i
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O ENCLOSURE SEQUOYAH NUCLEAR PLANT DIESEL GENERATOR LOADING SEQUENCES COMMITMENTS 1.
Plant modifications required to meet the coincident diesel loading sequences will be implemented prior. to restart of the respective units.
2.
TVA will reviso the FSAR to identify that only the coincident diesel generator loading sequences are design basis events in the 1988 annual update.
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