ML20077D208
| ML20077D208 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 05/20/1991 |
| From: | Wallace E TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9105280199 | |
| Download: ML20077D208 (4) | |
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MAY 2 01991 l
i U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555 Gentlemen:
1 In the Matter of
)
Docket Nos. 50-327 Tennessee Valley Authority
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50-328 SEQUOYAH NUCLEAR PLANT (SQN) UNITS 1 AND 2 - DOCKET NOS. 50-327 AND 50-328 - FACILITY OPERATING LICENSES DPR-77 AND 79 - SPECIAL REPORT 91 04 The enclosed special report provides details concerning the inoperability l
of the auxiliary building fire suppression water system.
This condition j '
was initially reported by telephone-notification-at 1453 Eastern daylight _.
time on May 7, 1991, and confirmed by facsimile on the same day, in i
accordance with SQN's technical specifications.
This report is being submitted in accordance with Action Statement (b)(2)(c) of LCO 3.7.11.1.
If you have any questions concerning this submittal, please telephone J. W. Proffitt at (615) 843-6651.
Very truly yours, I
TENNESSEE VALLEY AUTHORITY c -c E. G. Wallace Nuclear Licensing and
. Regulatory. Affairs Enclosure cc: See page 2 9105280199 910520~
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2 U.S. Nuclear Regulatory Commission id/4Y 2 01991 cc (Enclosure):
Ms. S. C. Black, Deputy Director Project Directorate 11-4 U.S. Nuclear Regulatory Commlosion One White Flint, North 11555 Rockville Piko Rockville, Maryland 20852 Mr. D. A. LaBarge, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20032 NRC Resident Inspector Sequoyah Nuclear Plant 2600 Igeu Ferry Road Soddy Daisy, Tennessee 37379 Mr. B. A. Wilson, Project Chief U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 l
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I ENCLOSURE 14 Day Follow-Up Report Special Report 91-04 Descrip_t_lon of Condition On May 6, 1991, at 1600 Eastern daylight time-(EDT), with Units 1 and 2 operating in Mode 1 at 100 percent power, Limiting Condition for Operation (LCO) 3.7.11.1 was entered when the fire suppression water system for the auxiliary building was declared inoperabic.
SQN Technical Specification (T3) LCO 3.7.11.1 requires the fire suppression water system to be demonstrated operable at least once overy 3 years by performing a flow test of the system in accordance with Chapter 5, Section ll, of the Fire protection Handbook, 14th Edition, published by the National Fire protection Association.
SQN implements this requirement annually for the auxiliacy building fire protection system by performance of Surveillance Instruction (SI) 0-SI-SPT-026-002.0, " Auxiliary Building Syatem Hydraulic performance Verification."
This test was performed on April 11, 1991, and the system declered operable.
However, on May 6, 1991, the fire protection engineer, while reviewing the test package, alscovered that the test data did not satisfy the acceptance
- criteria, i.e.,
the discharge pressure of the fire pumps was below that required for a flow rate test. The test was invalidated, the system declared inoperable, and LCO 3.7.11.1 was entered at 1600 EDT for Units 1 and 2.
Although the water suppression system was declared inoperable, the fire pumps were operable and the flow paths intact and two additional pumps are also available.
Accordingly, the existing system is being utilized to meet the requirements of Action Statement (b)(1) for LCO 3.7.11.1.
0-SI-SFT-026-002.0 provides the detailed instructions to determine the hydraulic performance of the auxiliary building high pressure fire protection system. The test measures static pressure, residual pressure, and velocity pressure when a flow is imposed on selected auxiliary building hose stations (a total of nine test configurations are evaluated). The first five configurations are_used to_ collect data for trending purposes to determine system degradation _(no acceptance criteria required). The last four test configurations are used to obtain data that is compared with acceptance criteria to demonstrate operability of the system.
On April 11, 1991, the test data did not meet the acceptance criteria as stated in the S1 for the last four test configurations. The reason for the system performance f ailure and also why the failure was not recognized until May 6, 1991, is still under investigation. The results of this investigation to identify the causes and corrective actions for this event will be reported in LER S0-327-91009, which is due to NRC on June 5, 1991.
The auxiliary building-fire suppression system is described in the Updated Final Safety Analysis Report, Section 9.5.1.
Arla_1ysis of Condition Thic event is being reported in accordance with the requirements of Action Statement (b)(2)(c) of LCO 3.7.11.1.
The fire suppression system while being technically inoperable is functional.
While the test was performed with only two fire pumps oferating (in accordance with technical specification), all four pumps were operable and available to be placed in service in the event of a fire.
Additionally, the fire suppression water system was capable of delivering suppression water and serving as the backup fire suppression water system.
Corrective Action The immediate corrective action was to declare the system inoperable and enter LCO 3.7.11.1.
The test was reperformed on May 7, 1991, and the system was determined to be inoperable and the backup fire suppression system was established. The syste_a was inspected and repairs have been made as appropriate. The strainers on the dedicated lines have been cleaned and/or replaced. Valves that were identifled as having 1cakage problems have been repaired or replaced as appropriate.
Further details will be reported in the aforementioned LER regarding corrective actions and actions to prevent recurrence.
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