ML20207S854
| ML20207S854 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 03/16/1987 |
| From: | Druga R DUQUESNE LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| ND1SS1:3100, NUDOCS 8703200332 | |
| Download: ML20207S854 (4) | |
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'Af Telephone (412) 393-6000 Nuclear Group P.O. Box 4 Shippingport. PA 15077 0004 March 16. 1987 NDISS1:3100 Beaver Valley Power Station, Unit No. 1 Docket No. 50-334. License No. DPR-66 Special Report United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Gentlemen:
In accordance with Technical Specification 3.7.14.1, the following special report is submitted:
On March 5, 1987, both of Beaver Valley's fire suppression system high pressure pumps were inoperable from 1125 houcs to 1259 hours0.0146 days <br />0.35 hours <br />0.00208 weeks <br />4.790495e-4 months <br />. The electrical motor driven fire pump [FP-P-11 had been removed from service at 0045 hours5.208333e-4 days <br />0.0125 hours <br />7.440476e-5 weeks <br />1.71225e-5 months <br /> on March 5, 1987, for maintenance on its auto-start pressure switch. At 1116 hours0.0129 days <br />0.31 hours <br />0.00185 weeks <br />4.24638e-4 months <br /> on March 5, 1987, the " Engine Driven Fire Pump Local Panel Trouble" alarm in the control room began flashing in and out of the alarm condition.
Locally, an operator discovered that the diesel driven fire pump [FP-P-2J was repeatedly attempting to auto-start. This continued until the operator placed the local control switch for [FP-P-2]
in the OFF position at 1125 hours0.013 days <br />0.313 hours <br />0.00186 weeks <br />4.280625e-4 months <br /> on March 5, 1987. At this time, both fire pumps were inoperable.
Efforts were immediately initiated to return IFP-P-1} to service. The pump was returned to service and started running at 1259 hours0.0146 days <br />0.35 hours <br />0.00208 weeks <br />4.790495e-4 months <br /> on March 5, 1987. The only maintenance that had been performed on the pump was on its pressure switch. The pressure switch provides an auto-start signal to the pump on low header pressure. As the pressure switch had not been tested after maintenance, [FP-P-1} was started and left running until the switch could be tested. The pressure switch was tested successfully at 1045 hours0.0121 days <br />0.29 hours <br />0.00173 weeks <br />3.976225e-4 months <br /> on March 6, 1987. At this time, [FP-P-11 was stopped and placed in its normal standby condition.
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a March 16, 1987 NDISS1:3100 Page 2 Investigation found that the starting batteries for (FP-P-2] were discharged. After charging the batteries, the pump operated properly.
The pump was tested and returned to service at 1750 hours0.0203 days <br />0.486 hours <br />0.00289 weeks <br />6.65875e-4 months <br /> on March 6, 1987.
The root cause of this event was determined to be a clogged line between the fire suppression system header and the hydropneumatic tank.
The hydropneumatic tank is a pressurized tank used as a surge volume to maintain a constant pressure on the fire suppression system under no flow conditions.
Pressure is normally maintained in the hydropneumatic tank using compressed air. Water level is maintained using a small capacity (30 gpm) makeup pump. During a fire suppression system actuation, the hydropneumatic tank's level / pressure control system is insufficient to maintain header pressure. As header pressure drops, [FP-P-1] receives an auto-start signal.
If header pressure continues to drop, [FP-P-2] will receive an auto-start signal.
For two (2) days prior to this event, [FP-P-1] had been experiencing several spurious auto-starts per day. These auto-starts were the reason that station personnel suspected that [FP-P-1] might have an inoperable pressure switch.
In actuality, the pressure switch was functioning properly. After the line between the hydropneumatic tank and the header became clogged, the header would lose pressure due to normal 7ystem leakage. When a sufficient pressure drop had occurred, [FP-P-1] would start and re pressurize the header. However, after [FP-P-1] was removed from service at 0045 hours5.208333e-4 days <br />0.0125 hours <br />7.440476e-5 weeks <br />1.71225e-5 months <br /> on March 5, 1987, the header pressure dropped until [FP-P-2] started and re-pressurized the system.
[FP-P-2]
successfully started and re pressurized the header four (4) times between 0045 and 1027 hours0.0119 days <br />0.285 hours <br />0.0017 weeks <br />3.907735e-4 months <br /> on March 5, 1987. On each occasion, [FP-P-2] was shut down within a few minutes of starting after the operators had verified that the fire suppression system had not actuated. At 1116 hours0.0129 days <br />0.31 hours <br />0.00185 weeks <br />4.24638e-4 months <br /> on March 5, 1987, the fire suppression system header de pressurized to the [FP-P-2]
auto-start setpoint.
[FP-P-2] attempted to start but was unable to since the four (4) previous starts had discharged the pump's batteries.
[FP-P-2] had not been allowed to run long enough after any of its four (4) starts for its generator to recharge its batteries. The batteries also have a normally operating float changer but it was insufficient to recharge the batteries after its series of starts.
Beaver Valley has rodded out the line between the hydropneumatic tank and fire suppression system header. Additionally, Beaver Valley plans to replace this line with new piping to ensure it is totally free of blockage. A precaution was added to the operating manual, and a permanent caution tag will be posted at the engine driven fire pump control cabinet to ensure that the pump is allowed to run for at least 30 minutes after any start to charge its batteries.
March 10, 1987 NDISS1:3100 Page 3 There were no safety implications due to this incident.
In the event that a fire had occurred during the period when both fire pumps were inoperable an emergency _ cross-connect from the safety-grade river water system was available to supply water to the_ fire suppression system.
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R. J. Druga Acting Plant Manager DSC/ vat
March _16, 1987 NDISS1:3100 Page 4 cc: Dr. Thomas E. Murley Regional Administrator-United States Nuclear Regulatory Commission Region 1 King of Prussia, PA 19406 C. A. Roteck, Ohio Edison Mr. Peter Tam, BVPS Licensing Project Manager
~ United States Nuclear Regulatory Commission Washington, DC 20555 W. Troskoski, Nuclear Regulatory Commission, BVPS Site Inspector Mr. Alex Timme, CAPCO Nuclear Projects Coordinator, Toledo Edison INPO Records Center Suite 1500 1100 Circle 75 Parkway Atlanta, GA 30339 G. E. Muckle, Factory Mutual Engineering, Pittsburgh Mr. J. A. Triggiani, Operating Plant Projects Mancger Mid Atlantic Area Westinghouse Electric Corporation Nuclear Services Integration Division Box 2728 Pittsburgh, PA 15230 American Nuclear Insurers c/o Dottie Sherman, ANI Library The Exchange Suite 245 270 Farmington Avenue Farmington, CT 06032