ML20069L086
| ML20069L086 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 06/07/1994 |
| From: | Powers K TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TAC-M68603, TAC-M68604, NUDOCS 9406170184 | |
| Download: ML20069L086 (3) | |
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Tumw, vey eveonty rost ortco Ebv 20Co. CaPJy Dasy Tennewy,37379 2000 l
Ken Powers vee Presount. Sup>y3h Nude Fbnt June 7, 1994 U.S. Nuclear Regulatory Commission j
ATTN: Document Control Desk Washington, D.C. 20555 j
Gentlemen:
In the Matter of
)
Docket Nos. 50-327 i
Tennessee Valley Authority
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50-328 I
SEQUOYAH NUCLEAR PLANT (SQN) - UNITS 1 AND 2 - COMMI'INENT STATUS AND
(
JUSTIFICATION FOR IMPLEMENTATION OF THE STATION BLACK 0UT (SBO) RULE (10 CFR 50.63) (TAC NOS. M68603 AND M68604)
References:
1.
NRC letter to TVA dated June 11, 1992, " Supplemental l
Safety Evaluation (SSE) - Station Blackout Analysis, Sequoyah Nuclear Plant Units 1 and 2 (TAC Nos. M68603 and M68604)"
2.
IVA letter to NRC dated April 16, 1992, "Sequoyah Nuclear Plant (SQN) - Units 1 and 2 - Response to NRC Safety Evaluation (SE) on the Conformance With the Station Blackout (SBO) Rule (10 CFR 50.63)"
The purpose of this letter is to provide NRC with the current status and justification for implementing SQN SB0 commitments (reference 10 CFR 50.63, paragraph [c}[4]).
By Reference 2, TVA provided NRC with the schedule for completing remaining SB0 commitments. While three of the five commitments have been completed,-the Unit 1 and Unit 2 commitments to install new fail-open level control valves on the turbine-driven auxiliary feedwater (AFW) pump are scheduled for completion prior to restart from the Unit 1 Cycle 7 and the Unit 2 Cycle 6 refueling outages, respectively.
In Reference 1, NRC acknowledged and accepted this schedule with the understanding that the Unit 1 Cycle 7 refueling outage would exceed the preferred two-year implementation period for SB0 actions, while the Unit 2 Cycle 6 refueling outage was expected to occur within the two-year implementation period.
9406170184 940607 I
PDR ADDCK 05000327 Q'
P PDR l
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1 U.S. Nuclear Regulatory Commission Page 2 June 7, 1994 SQN has experienced extended forced outages affecting Units 1 and 2 since the exchange of the referenced letters. These forced outages have in no way altered TVA's commitment to carry out the remaining SB0 commitments; however, the duration of these outages has pushed the timing for commitment completion further beyond the preferred two-year SB0 implementation period.
The Unit 1 commitment was previously expected to exceed the two-year milestone of June 15, 1994, by approximately four montte; however, a projected Unit 1 Cycle 7 outage date of September 1995 means that Unit 1 commitment completion could occur approximately 15 months beyond the two-year milestone.
In addition, the Unit 2 Cycle 6 refueling outage, presently scheduled for July 1994, means that the Unit 2 commitment completion will exceed the June 15, 1994, date by approximately three months.
The extended forced outages affecting both Units 1 and 2 were of a nature and scope that precluded TVA from carrying out its remaining SB0 commitments.
The outages were completely unforeseen, occurring without sufficient warning and without adequate knowledge of required outage duration to pursue the modifications. Moreover, even if TVA had been able to foresee the duration of the forced outages with any reasonable certainty, the critical activities that were necessary to return the units to power operation would have taken precedence over the planning and procurement activities necessary to provide for the early implementation of the SB0 commitments.
SQN has initiated compensatory measures to ensure that the Operations staff has sufficient manpower to manually operate the AFW 1evel control valves during accident conditions. These compensatory measures will provide local AFW 1evel control valve operation to maintain acceptable steam generator levels throughout the postulated four-hour SB0 duration.
These measures will be maintained until the modifications have been completed on the valves that will provide remote operation capabilities for the postulated SB0 event duratiou.
There are no new commitments contained in this submittal.
Please direct questions concerning this issue to K. C. Weller at (615) 843-7527.
Sincerely Ken Powers cc:
See page 3
U.S. Nuclear Regulatory Commission Page 3 June 7, 1994 cc:
Mr. D. E. LaBarge, Project Manager U.S. 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 II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323-2711
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