05000354/LER-2001-001

LER-2001-001,

Docket Number
Event date:	05-08-2001
Report date:	07-06-2001
Reporting criterion:	10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
3542001001R00 - NRC Website

PLANT AND SYSTEM IDENTIFICATION

General Electric — Boiling Water Reactor (BWR/4) Main Steam Isolation Valve Sealing System {BD}* 4.16 kV Station Power {EB}* * Energy Industry Identification System (EllS) codes and component function identifier codes appear as {SS/CC}

IDENTIFICATION OF OCCURRENCE

Event Date: May 8, 2001 Discovery Date: May 8, 2001

CONDITIONS PRIOR TO OCCURRENCE

The plant was in OPERATIONAL CONDITION 1 (POWER OPERATION). At the start of this event, the inboard Main Steam Isolation Valve Sealing System was inoperable.

DESCRIPTION OF OCCURRENCE

On May 8, 2001 at approximately 1004 hours0.0116 days <br />0.279 hours <br />0.00166 weeks <br />3.82022e-4 months <br />, the Hope Creek Generating Station initiated a unit shutdown to comply with the provisions of Technical Specification (TS) 3.0.3. TS 3.0.3 was entered at 0820 hours0.00949 days <br />0.228 hours <br />0.00136 weeks <br />3.1201e-4 months <br /> when both trains of the Main Steam Isolation Valve Sealing System (MSIVSS) were declared inoperable.

The inboard ("A") MSIVSS had been inoperable since May 4, 2001 due to excessive steam leakage into the system through normally closed isolation valves {BD/ISV}. TS 3.6.1.4 permits continued operation for up to 30 days with one MS1VSS subsystem inoperable.

On May 8, 2001 at 0508 hours0.00588 days <br />0.141 hours <br />8.399471e-4 weeks <br />1.93294e-4 months <br />, a failure of a "C" Class-1E 4.16 kV bus potential transformer (PT) {EB/XPT} tripped two of the four channels of Loss of Voltage relay protection {EB/27} for that bus.

At 0820 hours0.00949 days <br />0.228 hours <br />0.00136 weeks <br />3.1201e-4 months <br />, it was determined that the PT failure also affected the "C" Emergency Diesel Generator (EDG) synchroscope {EBISYN}. The "C" EDG {EB/DG} was declared inoperable due to its inability to meet Surveillance Requirement (SR) 4.8.1.1.2.h.10 which requires verification of the diesel generator's capability to synchronize with the offsite power source while loaded with its emergency loads. With no power to the synchroscope, the "C" EDG could not be synchronized with the offsite power source. The PT failure had no effect on the "C" EDG's ability to automatically start and load in response to a loss of offsite power.

Since the "C" EDG is the standby electric power source for the outboard ("B") MSIVSS subsystem, both MSIVSS subsystems were considered inoperable and TS 3.0.3 was entered. The plant shutdown was completed at 1502 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.71511e-4 months <br /> on May 8, 2001.

DESCRIPTION OF OCCURRENCE (continued) This event is reportable as the completion of a plant shutdown required by the plant Technical Specifications in accordance with 10 CFR 50.73(a)(2)(i)(A), and as a condition prohibited by plant Technical Specifications in accordance with 10 CFR 50.73(a)(2)(i)(B). A four hour notification was made to the NRC in accordance with 10 CFR 50.72(b)(2)(i) on May 8, 2001 at 1244.

APPARENT CAUSE OF OCCURRENCE

The apparent cause of this event was the random failure of one of two "C" Class-1E 4.16 kV bus potential transformers. There were no indications of a generic problem such as manufacturing defects, aging, voltage surges or environmental stresses. The failure of the transformer caused two of the four channels of Loss of Voltage relay protection for that bus to trip. Voltage to the "C" EDG synchroscope was also lost. The failure of the potential transformer is attributed to a shorted primary winding. This short caused the two primary side fuses to open isolating the fault from the bus. The potential transformer, type JVM, 4200/120 vac is manufactured by General Electric.

The inoperability of the "A" MSIVSS subsystem was due to excessive leakage from the main steam system through normally closed MSIVSS isolation valves.

SAFETY SIGNIFICANCE AND IMPLICATIONS

There were no actual safety consequences associated with this event. The "B" MSIVSS subsystem remained capable of performing its safety function following a loss of offsite power coincident with a design basis loss of coolant accident.

A review of this event determined that a Safety System Functional Failure (SSFF) as defined in NEI 99-02 did not occur.

PREVIOUS OCCURRENCES

A review of previously reported events identified no instances within the last two years involving conditions prohibited by Technical Specifications due to component failure.

CORRECTIVE ACTIONS

1. The failed potential transformer for the "C" Class-1E 4.16 kV bus was replaced.

2. The inboard MSIVSS header isolation valve (KP-HV-5829A) was replaced.

COMMITMENTS

The corrective actions cited in this LER are voluntary enhancements and do not constitute commitments.