05000278/LER-2004-001

LER-2004-001, Loss of High Pressure Coolant Injection System Function as a Result of Inoperable Flow Controller

Peach Bottom Atomic Power Station, Unit 3
Event date:
Report date:
2782004001R00 - NRC Website

NAME

James Mallon, Regulatory Assurance Manager TELEPHONE NUMBER (Include Area Code) (717) 456-3351

CAUSE SYSTEM COMPONENT

MANU-

TO EPIX CAUSE SYSTEM COMPONENT

MANU-

TO EPIX

B BJ TC M430 Y _ 14. SUPPLEMENTAL REPORT EXPECTED 15. EXPECTED

MONTH DAY YEAR

I YES (If yes, complete EXPECTED SUBMISSION DATE) I X I NO 16. ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) On 3/17/04, at approximately 1235 hours0.0143 days <br />0.343 hours <br />0.00204 weeks <br />4.699175e-4 months <br />, during the performance of a routine surveillance t test t for t the t High t Pressure t Coolant t Injection t (HPCI) t system, Operations personnel discovered that HPCI was inoperable. During performance of the surveillance test, the HPCI turbine could not achieve a speed above 1000 rpm and no significant discharge pressure was observed. Within two minutes of the initial turbine start, HPCI was tripped and the steam supply isolation valve was closed. The cause of the event is due to an inoperability of the HPCI system flow controller. The HPCI controller was discovered to not respond properly. The flow controller was replaced. HPCI was satisfactorily tested and returned to an operable status on 3/19/04 by 0145 hours0.00168 days <br />0.0403 hours <br />2.397487e-4 weeks <br />5.51725e-5 months <br />. Other flow related components on the HPCI system were evaluated and found to be in an acceptable condition. Other similar flow controllers (HPCI and RCIC) on Units 2 and 3 were evaluated for extent of condition concerns and determined to be operable. There were no actual safety consequences associated with this event.

Unit Conditions Prior to the Event Unit 3 was in Mode 1 and operating at approximately 100% rated thermal power when the event occurred. There were no structures, systems or components out of service that contributed to this event.

Description of the Event

On 3/17/04, at approximately 1235 hours0.0143 days <br />0.343 hours <br />0.00204 weeks <br />4.699175e-4 months <br />, during the performance of a routine surveillance test for the High Pressure Coolant Injection (HPCI) (EIIS: BJ) system, Operations personnel discovered that HPCI was inoperable. During performance of the surveillance test, the HPCI turbine (EIIS: TRB) could not achieve a speed above 1000 rpm and no significant discharge pressure was observed.

Within two minutes of the initial turbine start, HPCI was tripped and the steam supply isolation valve (EIIS: ISV) was closed.

This condition was reported to the NRC on 03/17/04 at approximately 1519 hours0.0176 days <br />0.422 hours <br />0.00251 weeks <br />5.779795e-4 months <br /> pursuant to the requirements of 10CFR 50.72(b)(3)(v)(D) (Event Notification # 40593).

Troubleshooting of the HPCI system determined that the HPCI system flow controller (EIIS: TC) was inoperable resulting in the HPCI turbine not achieving proper speed and therefore, not developing discharge pressure. The flow controller was replaced. HPCI was satisfactorily tested and returned to an operable status on 3/19/04 by 0145 hours0.00168 days <br />0.0403 hours <br />2.397487e-4 weeks <br />5.51725e-5 months <br />.

Analysis of the Event

There were no actual safety consequences associated with this event.

HPCI was considered as Technical Specification inoperable from 03/17/04 at approximately 1235 hours0.0143 days <br />0.343 hours <br />0.00204 weeks <br />4.699175e-4 months <br /> to 03/19/04 at approximately 0145 hours0.00168 days <br />0.0403 hours <br />2.397487e-4 weeks <br />5.51725e-5 months <br />. During this time period, other core cooling systems (Automatic Depressurization System (ADS) (EIIS:

RV), Core Spray (EIIS: BM) and Low Pressure Coolant Injection (EIIS: BO)) were fully operable. The Reactor Core Isolation Cooling (RCIC) system (EIIS: BN) was operable through this time period except for a brief inoperability on 3/18/04 from approximately 0600 to 0605 hours0.007 days <br />0.168 hours <br />0.001 weeks <br />2.302025e-4 months <br /> (approximately 5 minutes) due to inadvertent flow adjustment of the RCIC flow controller during Instrumentation & Control maintenance work intended to be performed on the HPCI flow controller. Licensed Operators promptly detected the condition and returned the RCIC system to an operable status. Technical Specification actions were appropriately taken. This coincident inoperability of HPCI and RCIC was reviewed and determined to not be risk significant.

A review of HPCI operations was performed by Engineering personnel to determine the length of time this condition may have existed. HPCI was operated for a routine surveillance test on 12/18/03 with no abnormalities noted. The exact time of controller failure between 12/18/03 and 3/17/04 could not be determined due to the nature of the failure.

This event is not considered to be risk significant.

Cause of the Event

Troubleshooting of the HPCI system determined that the HPCI system flow controller was inoperable resulting in the HPCI turbine not achieving proper speed and therefore, not developing discharge pressure. The cause of the event is due to an inoperability of the HPCI system flow controller. The HPCI controller was discovered to not respond to faceplate manipulations. Flow controller output was measured and found to not meet specifications.

The flow controller (FC-3-23-108) was sent off-site for further analysis. It was determined that the power supply board within the controller had failed.

The flow controller is a Moore Controller, Model # 352EA21NNF and has been in service since 1994. The Power Supply is a Micro 352, 120/240 Volt Plug-in Power Supply (part no. 1455-123).

Corrective Actions

The flow controller was replaced. HPCI was satisfactorily tested and returned to an operable status on 3/19/04 by 0145 hours0.00168 days <br />0.0403 hours <br />2.397487e-4 weeks <br />5.51725e-5 months <br />.

Other flow related components on the HPCI system were evaluated and found to be in an acceptable condition.

Other similar flow controllers (HPCI and RCIC) on Units 2 and 3 were evaluated for extent of condition concerns and determined to be operable.

Additional corrective actions are being evaluated in accordance with the corrective action program including evaluating the appropriateness of the controller preventative maintenance frequency.

Previous Similar Occurrences There were no previous similar LERs identified involving a loss of HPCI safety function due to an inoperable flow controller.