Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 43225 | 9 March 2007 14:32:00 | Appendix J Local Leak Rate Testing has determined that Tech Spec Acceptance Criteria for Secondary Containment Bypass Leakage has been exceeded. During the performance of SE-259-044 the combined SCBL limit of 9scfh was exceeded. Test results were within Administrative and Acceptance Criteria for the 10CFR50 Appendix J limits of 0.6La. The leakage limit is 9scfh. The identified degraded condition is reportable as a condition of the nuclear power plant, including its principle safety barriers being seriously degraded per 10CFR50.72(b)(3)(ii). The NRC Resident Inspector was notified of this event by the licensee. |
| ENS 42642 | 15 June 2006 05:05:00 | At approximately 0300 hours on 15 June, the Susquehanna Unit One reactor automatically scrammed due to an apparent neutron monitoring trip while transferring Reactor Protection System power supplies. All rods (fully) inserted, and both reactor recirculation pumps tripped. Reactor water level lowered to -38" causing level 3 (+13") and level 2 (-38")isolations, and was restored to normal level (+35") by RCIC and subsequently the feedwater system. All isolations at this level occurred as expected. No steam relief valves opened. Pressure was controlled via turbine bypass valve operation. All safety systems operated as expected. A reactor recirculation pump was restarted to re-establish forced core circulation. The reactor is currently stable in condition 3. An investigation into the cause of the shutdown is underway. Unit Two continued power operation. The NRC resident inspectors were notified. A press release will occur. After the scram, HPCI automatically started but was manually shut down with RCIC maintaining vessel level. Decay heat removal is being maintained with main feedwater and the turbine steam dumps. The electrical grid is stable. No major LCOs were in affect at the time of the event. |
| ENS 41746 | 6 June 2005 15:44:00 | At approximately 1233 hours, the Susquehanna Unit Two reactor automatically scrammed due to an apparent generator load reject. All rods inserted, and both reactor recirculation pumps tripped. Reactor water level lowered to -6" causing level 3 (setpoint +13") isolations, and was restored to normal level (+35") by the feedwater system. All isolations at this level occurred as expected. Two steam relief valves opened, then reclosed. Pressure was subsequently controlled via turbine bypass valve operation. All safety systems operated as expected. Some balance of plant loads shutdown apparently due to a voltage perturbation. A reactor recirculation pump was restarted to re-establish forced core circulation. The reactor is currently stable in condition 3. An investigation into the cause of the shutdown is underway. Unit One continued power operation. The NRC resident inspectors were notified. A press release will occur. The licensee will be notifying the State of Pennsylvania. |
| ENS 41640 | 26 April 2005 07:41:00 | At 0731 hours (EDT) on 04/26/2005 the Unit 2 SPDS system was removed from service for planned maintenance. The duration of work is expected to be 48 hours (scheduled for completion at 0700 hours (EDT) on 04/28/2005). ERDS will remain operable during the work window but several points will not be available. For example 23 of 58 ERDS points will be unavailable while SPDS is out of service. However, the ERDS system will still be operable and transmit the remaining points. Loss of Emergency Assessment Capability - A review of the ability of the emergency organization to function without SPDS was performed. Alternate sources for many of the points in SPDS were identified and are contained on an Emergency Plan format in PICSY (plant integrated computer system). Those points not available from PICSY can be obtained from the control room. With these compensatory actions and the communications in place between the facilities, there will not be a major loss of emergency assessment capability. Since the Unit 2 SPDS computer system will be unavailable for greater than 8 hours, this is considered a Loss of Emergency Assessment Capability and reportable under 10CFR50.72(b)(3)(xiii). The NRC Resident Inspector has been notified.
This is a followup courtesy notification to EN#4160. The Unit 2 SPDS system as noted below (above) has been restored to normal at 13:52 (EDT) on 4/28/05 The licensee notified the NRC Resident Inspector. Notified R1DO (Barkley). |
| ENS 41463 | 6 March 2005 15:25:00 | The following information was provided by the licensee via facsimile (licensee text in quotes): At 1500, on March 6, 2005, the Control Room declared both required divisions for three functions (Primary Containment Pressure, Primary Containment Hydrogen and Oxygen Analyzer, and Drywell Atmosphere Temperature) of Post Accident Monitoring Instrumentation (a Safety System) inoperable. The control room was notified of 'Non Quality' (non-Q) parts installed in both required divisions of a Post Accident Monitoring Instrumentation Recorder. The appropriate LCO Conditions were entered for one or more functions with two required channels inoperable. This equipment has passed all surveillance requirements and has been functional since installation. Plans are being developed to replace the non-qualified parts. This is being reported as an event or condition that could have prevented fulfillment of a safety function required to mitigate the consequences of an accident in accordance with 10CFR50.72(b)(3)(v)(D). The licensee notified the NRC Resident Inspector.
The following information was provided by the licensee via facsimile (licensee text in quotes): On March 6, 2005, PPL Susquehanna, LLC reported a perceived loss of safety function for three functions of Post Accident Monitoring Instrumentation on Unit 1. The notification was made pursuant to the reporting requirements of 10CFR50,72(b)(3)(v)(d). Engineering analysis has subsequently determined that the use of non-Q fuse holders in the Quality application did not adversely affect the safety-related functions which they supported. The fuse holders were removed, subjected to testing, and determined to be electrically and functionally equivalent 'to Quality fuse holders maintained at the station. This analysis conclusion provides the basis for retraction of the ENS report of March 6. The NRC Resident Inspector was notified. The Reg 1 RDO (Jim Trapp) was informed. |
| ENS 40948 | 13 August 2004 11:22:00 | At 08:00 on 8/13/04 Computer Maintenance personnel discovered the Unit 1 SPDS computer was not updating properly. A review into the history identified that the SPDS computer had stopped updating at 21:00 on 8/12/04. The Control Room was notified. The computer group was successful in resetting the SPDS computer and is now properly operating. Since the Unit 1 SPDS computer system was unavailable for greater than 8 hours, this is considered a loss of Emergency Assessment Capability and therefore reportable under 10CFR50.72(b)(3)(xiii). The licensee informed the NRC Resident Inspector. |
| ENS 40605 | 23 March 2004 11:00:00 | Unit 1 is currently in a refueling outage in Mode 5. During a routine inservice inspection of the reactor vessel, an indication was discovered on the N1B penetration. This is associated with the suction for B Loop of Reactor Recirculation. At 0746 on 3/23/2004, the Control Room was notified that the evaluation was completed and the indication was determined to be unacceptable under the ASME Section XI Code. Based on guidance provided in NUREG-1022, Rev. 2, this material defect in the primary coolant boundary constitutes a seriously degraded condition and is reportable under 10CFR50.72(b)(3)(ii)(A). A final evaluation of the flaw and a repair plan is being developed. The licensee informed the NRC Resident Inspector.
On March 23, 2004, PPL Susquehanna, LLC reported a material defect discovered on the N1B penetration associated with the suction for the B Loop of Reactor Recirculation. The defect was discovered during routine inservice inspection of the reactor vessel. At the time of the report, the indication was believed to exceed the acceptability standards of ASME Section XI, IWB-3640. Accordingly, an ENS call was made pursuant to the reporting requirements of 10CFR50.72(b)(3)(ii)(A). Engineering analysis subsequently determined that the dimensional characteristics of the flaw were within the acceptability requirements of ASME Section Xl. This analysis conclusion provides the basis for retraction of the ENS report of March 23. Although hypothetical flaw growth calculations demonstrated that the flaw size would remain within the allowable envelope of ASME Section Xl, IWB-3641-1 over the next operating cycle, and continued operation without repair of the observed flaw was justified, PPL Susquehanna, LLC performed a weld repair of the defect during the recently completed refueling outage. Notified the R1DO (R. Barkley) |
| ENS 40574 | 7 March 2004 09:01:00 | At 0201 on 03/07/2004, with Susquehanna Unit 1 in its 13th Refueling and Inspection Outage, the 'A' Emergency Diesel Generator auto started during preparations for a scheduled 1A ESS(Emergency Service Supply) Bus outage. While performing the procedure for removal of the ESS Bus from service, two incorrect fuses were removed. This caused the normal supply breaker to open on sensed undervoltage deenergizing the 1'A' ESS Bus. The alternate breaker also attempted to close as designed, but tripped open immediately due to the sensed undervoltage. With all breakers open, the 'A' Emergency Diesel Generator auto started and loaded onto the bus. All leads had previously been removed from the bus per the procedure. The 'A' Emergency Diesel Generator is operating as designed and is available to supply Unit 2 'A' ESS Bus if required. The auto start of a Emergency Diesel Generator is reportable as an event that results in the valid actuation of a system designed to mitigate the consequences of significant events per 10CFR50.72(b)(3)(iv)(A). The licensee notified the NRC Resident Inspector. |
| ENS 40509 | 9 February 2004 19:52:00 | On 2/9/04 PPL issued a Press Release concerning the NRC decision to send an Inspection team to investigate the cause of the loose bolts found on one of the Emergency Diesel Generator and two other events involving Emergency Diesel Generators at the Susquehanna site. The NRC Resident Inspector was notified. |
| ENS 40498 | 2 February 2004 17:33:00 | A contractor foreman/supervisor was determined to be under the influence of alcohol during a pre-access FFD test as part of processing for unescorted access. The supervisor was denied unescorted access to the protected area. Contact the HOO for additional details The licensee notified the NRC Resident Inspector. |