Event Notification Report for July 18, 1999
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
07/17/1999 - 07/18/1999
EVENT NUMBERS
35931
!!!!! THIS EVENT HAS BEEN RETRACTED !!!!!
!!!!! THIS EVENT HAS BEEN RETRACTED !!!!!
Power Reactor
Event Number: 35931
Facility: THREE MILE ISLAND
Region: 1 State: PA
Unit: [1] [] []
RX Type: [1] B&W-L-LP,[2] B&W-L-LP
NRC Notified By: BOB BOYER
HQ OPS Officer: STEVE SANDIN
Region: 1 State: PA
Unit: [1] [] []
RX Type: [1] B&W-L-LP,[2] B&W-L-LP
NRC Notified By: BOB BOYER
HQ OPS Officer: STEVE SANDIN
Notification Date: 07/18/1999
Notification Time: 20:41 [ET]
Event Date: 07/18/1999
Event Time: 18:07 [EDT]
Last Update Date: 07/20/1999
Notification Time: 20:41 [ET]
Event Date: 07/18/1999
Event Time: 18:07 [EDT]
Last Update Date: 07/20/1999
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(ii) - ESF ACTUATION
10 CFR Section:
50.72(b)(2)(ii) - ESF ACTUATION
Person (Organization):
JOHN WHITE (R1)
JOHN WHITE (R1)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | Y | 100 | Power Operation | 100 | Power Operation |
TWO OF THREE OPERATING REACTOR CONTAINMENT BUILDING (RCB) FANS UNEXPECTEDLY TRIPPED DURING TROUBLESHOOTING OF ENGINEERED SAFEGUARDS ACTUATION SIGNAL (ESAS) RELAYS BY A CONTROL ROOM OPERATOR (CRO).
"A CRO was checking the ESAS relays for noise, humming or signs of overheating after the relays had been exercised as a result of de-energizing VBB for 1B Inverter restoration. While trying to identify a humming relay the CRO touched what he thought was the frame of relay 1X1A RCB, but what he touched actuated the relay contacts. This caused AH-E-1B and AH-E-1C to trip.
"The crew restarted AH-E-1B and AH-E-1C and followed Alarm response B-1-5 '480V ES Motor Trip.' Electrical prints (209-570 and 209-592) were referred to and showed that the relay is a normally de-energized relay. It sends a signal to the 1S and 1T 480V under voltage circuit, DH-V-4B to open and AH-E-1B/C to trip. The UV relays were verified to have not actuated and they were manually reset as a precautionary measure. DH-V-4B was verified still closed.
"It is believed since the CRO only slightly moved the relay and AH-E-1B/C contacts are normally closed when the relay is de-energized and the other three relays are normally open, that the movement was enough to break the closed contacts but not enough to make up the open contacts."
The licensee will inform the NRC resident inspector.
* * * UPDATE AT 1337 ON 7/20/99 BY SCHORK RECEIVED BY WEAVER * * *
The event that occurred on July 18, 1999, was an invalid actuation that only involved the AH-E-1B and AH-E-1C fans that are part of the reactor building ventilation system. Therefore, the requirement for reporting this as an ESF actuation is exempted in accordance with 10CFR50.72(b)(2)(ii)(B)(3)(iii). Thus, GPU Nuclear is withdrawing the 4 hour report
A review of the reporting criteria of 10CFR50.73 found that the event is similarly not required to be reported and therefore GPU Nuclear will not be submitting a 30 day licensee event report regarding this issue.
Nonetheless, the event has been entered into the GPU Nuclear 10CFR50, Appendix B Corrective Action Program and the cause and corrective action taken in response to this event will be documented in accordance with that program.
The retraction of the 4 hour report has been discussed with W. Schmidt, the NRC Senior Resident Inspector.
The NRC Operations Officer notified the R1DO Jim Noggle.
"A CRO was checking the ESAS relays for noise, humming or signs of overheating after the relays had been exercised as a result of de-energizing VBB for 1B Inverter restoration. While trying to identify a humming relay the CRO touched what he thought was the frame of relay 1X1A RCB, but what he touched actuated the relay contacts. This caused AH-E-1B and AH-E-1C to trip.
"The crew restarted AH-E-1B and AH-E-1C and followed Alarm response B-1-5 '480V ES Motor Trip.' Electrical prints (209-570 and 209-592) were referred to and showed that the relay is a normally de-energized relay. It sends a signal to the 1S and 1T 480V under voltage circuit, DH-V-4B to open and AH-E-1B/C to trip. The UV relays were verified to have not actuated and they were manually reset as a precautionary measure. DH-V-4B was verified still closed.
"It is believed since the CRO only slightly moved the relay and AH-E-1B/C contacts are normally closed when the relay is de-energized and the other three relays are normally open, that the movement was enough to break the closed contacts but not enough to make up the open contacts."
The licensee will inform the NRC resident inspector.
* * * UPDATE AT 1337 ON 7/20/99 BY SCHORK RECEIVED BY WEAVER * * *
The event that occurred on July 18, 1999, was an invalid actuation that only involved the AH-E-1B and AH-E-1C fans that are part of the reactor building ventilation system. Therefore, the requirement for reporting this as an ESF actuation is exempted in accordance with 10CFR50.72(b)(2)(ii)(B)(3)(iii). Thus, GPU Nuclear is withdrawing the 4 hour report
A review of the reporting criteria of 10CFR50.73 found that the event is similarly not required to be reported and therefore GPU Nuclear will not be submitting a 30 day licensee event report regarding this issue.
Nonetheless, the event has been entered into the GPU Nuclear 10CFR50, Appendix B Corrective Action Program and the cause and corrective action taken in response to this event will be documented in accordance with that program.
The retraction of the 4 hour report has been discussed with W. Schmidt, the NRC Senior Resident Inspector.
The NRC Operations Officer notified the R1DO Jim Noggle.