Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 41103 | 8 October 2004 09:13:00 | On 10/08/04 on Unit Two, the HPCI Valve Operability was being performed. During the course of this evolution the suction path was transferred from the Condensate Storage Tank (CST) to the Suppression Pool. When the HPCI System was aligned to the Suppression Pool the Suction Pressure decreased from 25.5 psig to 1.5 psig. With HPCI aligned to the suppression pool and with suction pressure less than 14 psig the HPCI System was declared INOPERABLE. Investigation continues as to the cause of the low suction pressure. Preliminarily it is suspected that the Suppression Pool suction path was not adequately filled and vented following a recent tag out of that suction path for maintenance inspection activities. Investigation continues. The Licensee notified the NRC Resident Inspector.
The following information was obtained from the licensee via facsimile: The Unit 2 HPCI system was considered inoperable, since the technical information that would conclusively support its continued operability given the condition encountered could not be assembled within the time constraints of the reporting requirements. Subsequent to the event the system was confirmed be properly filled and vented with a negligible amount of air vented in the process. It was determined that this small amount of air was introduced to the suction piping as a result of an inspection activity performed for the HPCI suction check valve prior to the event. A limited amount of air remained in the torus suction piping causing the decrease in suction experienced during the event. Engineering reviewed the implications of the low suction pressure on the ability of the HPCI system to perform its safety function given the design of the system and the suction sources available. In each case Engineering was able to conclusively determine that the HPCI system would not have tripped due to low suction pressure had it received an automatic initiation signal and was actually operable during the time frame that Operations had conservatively treated the system as inoperable. Additionally, the effect of the trapped air being entrained in the pump suction was also analyzed, and the conclusion reached was that the air would not have prevented the pump's proper performance. Based on this information, the event reported on 10/08/2004 is not reportable. The licensee has notified the NRC Resident Inspector. The Headquarters Operations Officer notified R2DO (Bonser). |
| ENS 40649 | 6 April 2004 06:43:00 | The Plant Site detected a momentary loss of the NOAA Weather Radio System from 00:10 am on 04/06/04 to 00:14 am on 04/06/04. During this time interval of inoperability for this system, a major loss of off site notification capability is considered. Site Emergency Planning personnel were notified and will investigate this momentary loss of system capability. The NOAA Weather Radio System is currently in service and functioning properly. The licensee will notify the NRC Resident Inspector.
After further investigation, a determination has been made that there was no major loss of offsite notification capability of the Hatch Prompt Notification System (NOAA Weather Radio System). The momentary losses reported were caused by testing of the primary audio feed line utilizing a tone generator while investigating the loss of this feed. The secondary audio feed from Jacksonville NWS remained operable during the time of testing. The Licensee notified the NRC Resident Inspector. Notified R2DO (Decker) |
| ENS 40565 | 3 March 2004 17:01:00 | At the time of this occurrence Unit 1 is in a scheduled Refueling Outage and Unit 2 is at 100% Maximum Operating Power. Also note, the 1 B Diesel Generator is a Swing Diesel Generator which is capable of supplying Unit 1 1F 4160 Volt bus and also when required 2F 4160 Volt bus. At 13:45 EST on 03/03/04, the 1B Diesel Generator auto started due to a momentary Bus Undervoltage sensed on the 1F 4160 volt bus. At the time of the occurrence the 1F 4160 Volt bus was energized with the Normal Supply Breaker racked out and the Alternate Supply Breaker closed in and supplying the 1F 4160 Volt bus. The Normal Supply Breaker was racked out for a scheduled breaker replacement. At the time of the occurrence 2 electricians were removing the Racked Out Normal Supply breaker from the cubicle. The breaker shutter mechanism (a component of the breaker) fell off of the breaker inside the cubicle causing the 1F 4160 Volt bus to sense a momentary bus undervoltage, the Alternate Supply breaker momentarily cycled open and re-closed causing the 1B Diesel Generator to auto start. Since the 1 B Diesel Generator auto started from a valid signal (Bus Undervoltage) an 8 hour report is being made. At the time of this report the 1B Diesel Generator has been Shutdown and restored to a standby Lineup. The 1B Diesel Generator remains Operable. The licensee notified the NRC Resident Inspector.
Subsequent investigation revealed the most probable cause of this event was the trip of the alternate supply breaker to the emergency bus, resulting in its momentary de-energization and an automatic start of the diesel generator on an actual bus undervoltage signal. The alternate supply breaker apparently tripped as a result of the shutter in the formal supply breaker cubicle falling against the fingers of the breaker when as the breaker was being removed from the breaker cubicle. The affected breaker was already n the racked out position. When the breaker was moved to allow its removal from the cubicle, the shutter was apparently forced upward by the movement of the breaker musing the shutter to move upward and the shutter actuating lever to pivot downward until the moc switch mechanism actuated the logic causing the alternate supply breaker to -rip and the diesel generator to start. The shutter actuating lever became separated from the shutter allowing the moc switch to return to its expected open position thereby allowing the alternate supply breaker to recluse and provide power to the bus before the swing diesel generator had sufficient permissives to tie to the bus. Even with the condition found in this breaker cubicle the breaker can be safely racked out. It is when the breaker is removed from the cubicle that there is an increased potential for the shutter and its connected lever arm to cause a logic actuation similar to that experienced in this event. The condition does not create an operability concern for the bus and at most could cause a logic actuation in the conservative direction and does not present any known operability issues for the associated 4160 volt buses. Additional inspections have been performed on 6 balance of plant 4160 volt breakers that are identical in design with acceptable clearances observed in the locations where problems were noted in the subject breaker cubicle. The normal supply breaker for the 1F 4160V bus has been inspected with no problems noted. The associated shutter and lever mechanisms for this breaker have been inspected, components replaced and the breaker returned to service. The alternate supply breaker on the safety related 4160 volt switchgear that was involved in this event was also checked and found to have acceptable clearances and no problems noted with the shutter mechanism. At this point this condition is limited to the breaker cubicle that is the subject of this notification based on extent of condition review performed up this point. There are currently no operability concerns for the affected 4160 volt switchgear or associated diesel generator. Notified R2DO (R. HAAG). |
| ENS 40521 | 15 February 2004 11:16:00 | No System or Plant affect. At 08:22 AM EST, an injured Contractor worke(r) who was potentially contaminated was transported by ambulance to an offsite medical facility. The Contract employee fell approximately 15 to 20 feet in the Unit 1 Circulation Water box which is located in the Condenser Bay area. Unit 1 is presently in Cold Shutdown and in Mode 4 for a scheduled Refueling Outage. The employee received cuts to the forehead and nose and an injury to the arm and also some back pain. In an effort to provide medical treatment as the first priority, decontamination efforts were not completed on site and the individual was transported as potentially contaminated. The injured cont(r)act employee was also accompanied by a Health Physics Technician. Upon arrival at the hospital and while receiving medial care, the Health Physics technicians did discover a 500 dpm/cm2 spot of contamination on the back of the head of the injured person. Decontamination efforts are underway while medical treatment is rendered. The licensee notified the NRC Resident Inspector. |
| ENS 40428 | 6 January 2004 13:32:00 | Fire reported to control room at 1240 EST 01/06/04. Fire was located inside a portable "Kelly" building on the Refueling Floor which lasted greater than 10 minutes. An Unusual Event was declared at 1258 on 01/06/04. Fire was extinguished at 1302. Fire did not spread beyond the boundary of the Kelly building. The Kelly building was in a contaminated area, but there was no radioactive release outside of the Kelly building. Unusual Event was terminated at 1321. Initial notification to NRC Headquarters of the Unusual Event was made by the NRC Senior Resident Inspector at 1254 EST. At 1303 EST 01/06/04 the decision was made not to enter the Monitoring Phase of Normal Mode of Incident Response for this event. Licensee notified NRC Resident Inspector, State, and Local emergency management authorities. |
| ENS 40421 | 31 December 2003 16:19:00 | During a random drug test a Contractor tested positive. His access was revoked and he was escorted offsite. The contractor had full access to the Protected Area but he was working outside the Protected Area when he tested positive. A review of his past work will be performed. The NRC Resident Inspector will be notified of this event by the licensee. |