Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 47372 | 24 October 2011 20:14:00 | At 1715 hours on 10/24/2011, replacement of a router and circuit at the Emergency Operation Facility (EOF) commenced. This action will cause a temporary outage of network devices such as personal computers, telephones, printers, routers, switches, alarm panels, and wireless communications. The duration of work is expected to be approximately 8 hours. If use of the EOF is subsequently required, this condition may delay activation of the EOF until equipment is restored. Restoration of the equipment will take less than one hour. This is considered a Loss of Emergency Assessment Capability and reportable under 10CFR50.72(b)(3)(xiii). The licensee notified the State of Pennsylvania, Luzerne and Columbia Counties and the NRC Resident Inspector.
Systems have been restored and the EOF is operable. The licensee has notified the NRC Resident Inspector. Notified the R1DO (DeFrancisco). |
| ENS 47367 | 22 October 2011 01:56:00 | At 0857 on 10/21/2011 a condition was reported identifying that 10CFR Part 26 requirement for the FFD Lab Director to be subject to the FFD Rule was not met for the period of 12/12/2010 to 4/28/2011. 10CFR 26.4(g), 'FFD program applicability to categories of individuals,' provides specific requirements for FFD program personnel. Contrary to the above, the FFD Lab Director was not included in the (licensee's) random drug testing program as required by the regulation. This event is reportable under 10CFR26.719(b)4 requiring a 24 hour ENS notification. The NRC Resident Inspector has been notified. |
| ENS 46569 | 25 January 2011 08:12:00 | At 0610 EST hours on January 25, 2011, Susquehanna Steam Electric Station Unit 1 reactor was manually scrammed due to an unisolable extraction steam system leak in the 1C Feed Water Heater Bay area. At 0517 EST reactor operators commenced lowering reactor power from 98.4% to 65%. Attempts to isolate the source of the leakage were unsuccessful. Based on continued indications of unisolated steam leakage, operations decided to shut down the plant. The reactor operator placed the mode switch in shutdown. All control rods inserted. Reactor water level lowered to -31 inches causing Level 3 (+ 13 inches) isolation and RCIC initiation. The operations crew subsequently maintained reactor water level at the normal operating band using FW (feedwater). No steam relief valves opened. All safety systems operated as expected. RCIC automatically initiated on a -30 inch level signal and was manually secured. The reactor is currently stable in Mode 3. Investigation into the cause of the extraction steam system leakage is underway. The NRC Resident Inspector was notified. A voluntary notification to PEMA and press release will occur. The steam leak was isolated after the turbine was tripped. The plant is stable at normal temperature and pressure. Decay heat is being removed via the condenser steam dumps to the main condenser. The electrical lineup is in a normal configuration. Estimated time to restart is not known. |
| ENS 46519 | 3 January 2011 21:09:00 | On Monday, January 3, 2011, at 1344 EST, it was discovered by engineering that a single point of vulnerability exists at Susquehanna Steam Electric Station affecting both Unit 1 and Unit 2. A potential single HVAC control component has been discovered whose failure could result in a spurious Steam Leak Detection (SLD) isolation causing a loss of generation, loss of the normal heat sink (main condenser) and a loss of HPCI and RCIC. The SLD delta temperature (delta T) instrumentation is dependent on proper operation of the Unit 1 and Unit 2 RB (Reactor Building) HVAC heater temperature controller during cold weather operation. The Unit 1 and Unit 2 RB HVAC heaters are controlled by a single temperature controller which sends a signal to multiple step controllers. Failure of the temperature controller could cause the heaters to turn off. This would cause a significant decrease in RB HVAC supply temperature which results in a significant increase in measured SLD delta T during cold winter months. This could cause an isolation of the MSIVs, HPCI, RCIC and RWCU within a short period of time. This is reportable pursuant to 10CFR50.72(b)(3)(v) for a condition that at discovery could have prevented fulfillment of a safety function needed to mitigate the consequences of an accident and 10CFR50.72(b)(3)(ii) for and event that resulted in the nuclear power plant being in an unanalyzed condition. The licensee notified the NRC Resident Inspector.
On January 3, 2011, SSES reported the discovery of a single point vulnerability that affected both Unit 1 and Unit 2 (EN # 46519). The vulnerability involved failure of a temperature controller that had the potential to result in a Steam Leak Detection (SLD) isolation causing a loss of generation, loss of the normal heat sink (main condenser), and a loss of HPCI and RCIC. The condition was reported pursuant to 10CFR50.72(b)(3)(v) as a condition that at discovery could have prevented fulfillment of a safety function needed to mitigate the consequences of an accident and pursuant to 10CFR50.72(b)(3)(ii) as an event that resulted in the nuclear power plant being in an unanalyzed condition. SSES has further evaluated the condition and determined that the condition did not meet reporting criterion 10CFR50.72(b)(3)(v) for a condition that at discovery could have prevented fulfillment of a safety function needed to mitigate the consequences of an accident. The level of judgment in reporting under this criterion Is a reasonable expectation of preventing fulfillment of a safety function. Alternately stated, the condition is reportable if there was reasonable doubt that the safety function would have been fulfilled if the system had been called upon to perform it. Technical evaluation of the condition concluded the following: there is reasonable assurance (high degree of confidence) that the HPCI, RCIC, Main Steam Isolation and RWCU systems will remain operable. The identified condition does not adversely affect the operability of the affected systems. The identified condition increases the probability that a failure of the Reactor Building HVAC temperature controller TC-17589 or TC-27589 could cause the MSIV's, HPCI and RCIC to isolate during cold weather operation. However, this increase in probability is very small and is not sufficient to erode the confidence in the reasonable expectation of operability. For a system isolation to occur, the heater controller had to fail and concurrently the outside air temperature had to be below approximately 10?F. The Reactor Building HVAC temperature controllers are highly reliable and the outside air temperatures required for this event occur infrequently (there have only been 11 instances of temperatures at Susquehanna dropping below 10 deg F in the past two years). Since both infrequent conditions have to occur concurrently, it is unlikely that this postulated failure would occur. As a result, reporting pursuant to 10CFR50.72(b)(3)(v) is retracted; however, the condition remains reportable pursuant to 10CFR50.72(b)b)(3)(ii) as an event that resulted in the nuclear power plant being in an unanalyzed condition. The NRC Resident Inspector has been notified. Notified R1DO (T.Dimitriadis)
On January 3, 2011, SSES reported the discovery of a single point vulnerability that affected both Unit 1 and Unit 2 (EN #46519). The vulnerability involved failure of a temperature controller that had the potential to result in a Steam Leak Detection (SLD) isolation causing a loss of generation, loss of the normal heat sink (main condenser), and a loss of HPCI and RCIC. The condition was reported pursuant to 10CFR50.72(b)(3)(v) as a condition that at discovery could have prevented fulfillment of a safety function needed to mitigate the consequences of an accident and pursuant to 10CFR50.72(b)(3)(ii) as an event that resulted in the nuclear power plant being in an unanalyzed condition. On February 28, 2011, SSES retracted the 10CFR50.72(b)(3)(v) portion of the report on the basis that there was reasonable assurance that the HPCI, RCIC, Main Steam Isolation and RWCU systems would remain operable. The reasonable assurance was based on the very small probability of system isolation that required failure of the highly reliable heater controller had to fail concurrent with outside air temperature below approximately 10?F. This notification is intended to revise the basis for retraction of the 10CFR50.72(b)(3)(v) portion of the report. The revised basis is that the conditions required to prevent fulfillment of a safety function did not exist at the time of discovery. The licensee has notified the NRC Resident Inspector. Notified R1DO (Rogge). |
| ENS 46103 | 16 July 2010 20:03:00 | At approximately 1641 EDT on July 16, 2010, Susquehanna Steam Electric Station Unit 1 reactor was manually scrammed due to a large unisolable circulating water system leak in the main condenser area. Attempts to isolate the source of the leakage were unsuccessful. During these attempts, reactor operators lowered reactor power from approximately 90% to about 39%. Based on rising water level in the condenser area and unsuccessful isolation of the source of the leakage, Operations decided to shut down the plant. The reactor operator placed the mode switch in shutdown. All control rods (fully) inserted. Reactor water level lowered to -28 inches causing Level 3 (+13 inches) isolations. The Operations crew subsequently maintained reactor water level at the normal operating band using RCIC. No steam relief valves opened. The main steam isolation valves were manually closed and the circulating water system was shut down. Pressure control was initiated using HPCI in the pressure control mode. All safety systems operated as expected. The reactor is currently stable in Mode 3. Actions to isolate and investigate the cause of the circulating water system leakage are underway. Unit 2 continued power operation. The licensee has notified the NRC Resident Inspector, and will be issuing a press release. |
| ENS 41585 | 10 April 2005 12:08:00 | At 0352 the 2C 125VDC battery charger failed. Fuses internal to the charger were found blown. Technical Specifications require restoration of the charger within 2 hrs or enter Mode 3 within the next 12 hrs and Mode 4 within the next 36 hrs. Investigation has not been able to restore the charger, and therefore the shutdown of the unit has commenced. Loads are currently being carried by the batteries, and personnel are monitoring battery voltage. Initial investigation has not identified any generic issues or any indication of tampering. This event is a Technical Specification required shutdown, and is reportable as a four hour ENS Notification under 10 CFR 50.72(b)(2)(i). Additionally, this is a voluntary notification due to an anticipated press release associated with the downpower towards unit shutdown. There is evidence of degraded insulation on wires inside the affected battery charger. Battery loads are very small with an initial estimate of battery life at 80 hours. All safety systems are operable. There is no impact on Unit 1. Unit 2 is expected to reach Mode 3 at 1720 on 4/10/05. The NRC Resident Inspector has been notified. State (FEMA) will be notified.
At 17:28 the plant completed a normal reactor shutdown and entered Mode 3 in accordance with plant procedures to fulfill the requirements of Technical Specification 3.8.4. There were no ECCS initiations and lowest water level was approximately -4 inches. The licensee reported that the 2C battery charger was back in service but remained in the LCO due to battery requirements. They are also completing engineering evaluations for extent of condition. The NRC Resident Inspector was notified. R1DO (Noggle) notified.
At 16:28 on April 12th, 2005 Susquehanna Unit 2 entered Mode 2 (Start-up) following the completion of repairs to the failed 125VDC battery charger and inspection to the remaining 3 Unit 2 125VDC battery chargers. A courtesy call was made (to) the Pennsylvania Emergency Management Agency. An informational press release will be made. The NRC Resident Inspector was notified by the licensee. R1DO (White) was notified. |
| ENS 41506 | 21 March 2005 03:35:00 | The following information was obtained from the licensee via fax (licensee text in quotes): At 22:30 on 3/20/2005, the Control Room was notified by the test director that ASME CLASS I Boundary System Leakage Hydrostatic Pressure Test (SE-200-002) had failed. The reason was a leak identified on Reactor Recirc Pump B Discharge Valve, HV243F031B. The leak is coming from the Stub Tube Weld Leakoff Connection for the valve. It is leaking approx. 10 drops per minute. Technical Requirement 3.4.2 was entered. It 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 NRC Resident was notified. |
| ENS 41215 | 22 November 2004 18:27:00 | At 15:10 on 11/22/2004 Operations was notified of a condition that could have prevented the ability of Secondary Containment to control and monitor the release of radioactive material. Three primary system instrument lines have approximately a 20-foot run in an area that is not normally aligned to Secondary Containment. This area has been realigned to Secondary Containment until an analysis of this design can be completed. This has been determined to be reportable under 10CFR50.72(b)(3)(v)(C). Unit 1 is at 15% power with the main generator off line for unrelated repairs. The licensee notified the NRC Resident Inspector. |
| ENS 40777 | 26 May 2004 17:55:00 | This event is being reported under 10CFR50.72(b)(2)(xi) as an item of public interest and an event for which other government agencies have been notified. At 1600 on 5/26/2004, the operations Shift Manager was notified by the Security Shift Supervisor that an individual (truck driver) had been arraigned by a LLEA (Local Law Enforcement Agency) judge for prohibited items (drug paraphernalia) which were discovered during a routine entrance search of personnel and vehicles. The items were discovered outside the protected area (and) were determined to not pose a threat or attempted threat. The LLEA was called and responded to the site access area and removed the individual to the local barracks, where he was subsequently arraigned on a misdemeanor. The individual's name has been removed from the Susquehanna LLC visitors list. The Manager of Nuclear Security briefed NRC Region #1 Inspector, Dana Caran, concerning the incident. The licensee notified the NRC Resident Inspector. |
| ENS 40695 | 21 April 2004 18:06:00 | At 1635 on 04/21/2004, Susquehanna Unit 1 was returning to service from its 13th Refueling and Inspection Outage which included main turbine replacement. During start-up turbine testing with the generator off line, several main turbine bearings experienced high vibration. In response to these high vibrations, the reactor was manually scrammed from approximately 17% power. The main steam line isolation valves were manually closed and main condenser vacuum was broken in order to more rapidly slow the main turbine speed. All control rods fully inserted on the SCRAM, a level 3 containment isolation signal was received as expected. RCIC was manually initiated to control reactor water level. Lowest reactor water level reached was approximately 3" narrow range. There were no radioactive releases. This RPS actuation is reportable under 10CFR50.72(b)(2)(iv)(B) as an 'Unplanned RPS Actuation with the Reactor Critical.' The RPS Actuation and the RCIC injection are reportable per 10CFR50.72(b)(3)(iv)(A) 'Unplanned Actuations of Systems that Mitigate the Consequences of Significant Events.' Investigation into the high main turbine bearing vibrations is ongoing. The main turbine was tripped prior to the manual scram and no SRVs have lifted due to low decay heat level. The electric plant is in a normal lineup. The licensee notified the NRC Resident Inspector and the PEMA representative. |
| ENS 40573 | 7 March 2004 04:06:00 | At 22:10 on March 6, 2004 the Unit 1 Safety Parameter Display System (SPDS) was deenergized during planned refuel outage activities. It has been determined that it will not be restored within the required eight hours. Currently, restoration is scheduled for March 7, 2004 at 17:00. All required instrumentation is available in the control room. Since the Unit 1 SPDS computer system will be unavailable for greater than 8 hours, this is considered a Loss of Emergency Assessment Capability and therefore reportable under 10CFR50,72(b)(3)(xiii). Unit 1 is currently in Mode 5 for the planned 13th Refuel and Inspection Outage. The licensee notified the NRC Resident Inspector
SPDS is still out of service and it will be restored to service by 0600 EST on 03/08/04. R1DO (M. Shanbaky) notified. NRC Resident has be notified of the update by the licensee.
As of 1117 the SPDS was energized and restored to service. The NRC Resident Inspector was notified. Reg 1 RDO(Cobey) was notified. |
| ENS 40554 | 28 February 2004 02:02:00 | At 00:54 AM EST, the Main Control Room was notified than an individual had fallen approx. 12 feet from scaffolding. An ambulance was requested to the site, and arrived on site at 01:20. The individual is not contaminated and was transported to a local hospital at 01:40. PEMA (Pennsylvania Emergency Management Agency) was notified of the incident. The licensee informed the NRC Resident Inspector. |
| ENS 40486 | 29 January 2004 00:05:00 | At 2018 hrs, the Control Room was notified of smoke coming from the Unit 2 Vital UPS room. The Field Unit Supervisor (FUS) was dispatched to the room to investigate. At 2026 hrs, the Fire Brigade was activated. When the FUS arrived at the Vital UPS Panel he reported that there was smoke coming from the panel. He opened the panel and observed smoke coming from the transformer in the panel. He did not observe any flames at any time while dealing with the event. At 2029 hrs, Security was notified and subsequently notified the State Police at 2033 hrs. At 2033 hrs, the transformer was deenergized and the smoke began to dissipate. Entry into the Emergency Plan was evaluated and it was determined that no entry conditions exists at this time. Due to the notification of the Local Law Enforcement Agency, this event constitutes an Offsite Notification and therefore reportable under 10CFR50.72(b)(2)(xi) requiring a 4 hr ENS notification. When the transformer was deenergized, all loads were automatically transferred to the alternate power supply. The loss of this transformer did not affect any safety related equipment and does not require entry into any TS LCO Action Statements. The licensee notified state/local agencies and the NRC Resident Inspector. No press release is planned. |
| ENS 40367 | 2 December 2003 15:55:00 | At 1230 hrs, with both units at 100% power the Control Room was notified of a Medical Emergency at the Access Processing Facility on the Owner Controlled Area outside of the Protected Area. The affected individual was a contract employee working for Site Access Services. An ambulance and paramedics arrived on site at 1242 hrs. First Aid and CPR were initiated at the scene. The individual was transported offsite at 1257 hrs to the local Hospital. At 1415 hrs the control room was notified that the individual had passed away. This constitutes an event of public significance and therefore reportable under 10CFR50.72(b)(2)(XI) as a 4 hour ENS notification. The licensee notified the NRC Resident Inspector and Pennsylvania Emergency Management Agency. |
| ENS 40272 | 23 October 2003 21:30:00 | During routine monitoring, Control Room personnel noted control structure pressure differential was below the 1/8" (inches of water pressure) required to maintain the Control Structure Habitability Envelope. A walkdown of the Control Structure and initial investigation has revealed no obvious problems that would cause the low positive pressure condition. Due to the inability of the Control Structure HVAC to maintain a positive pressure, both trains of Control Room Emergency Outside Air Supply system were declared inoperable. This is considered a Loss of Safety Function in accordance with 10 CFR 50.72(b)(3)(v)(D). The licensee has notified the NRC Resident Inspector.
At the time of the original 8-hour ENS notification was made, both trains of the Control Room Emergency Outside Air Supply (CREOAS) system were declared inoperable due to the failure of the Control Structure HVAC system to maintain the control structure habitability envelope at a pressure greater than + 1/8" w.g. (water gauge) with respect to outside atmosphere. Subsequent to this event, an evaluation was performed which determined that the requirement to maintain the control structure habitability envelope at a pressure greater than + 1/8" w.g. is only applicable during emergency operating conditions. Under emergency conditions, the CREOAS system, in conjunction with the Control Structure HVAC system, is required to maintain control structure pressure greater than + 1/8" w.g. in accordance with Technical Specification 3.7.3. However, during normal plant operation, the design function of the Control Structure HVAC system is to maintain the habitability envelope at a positive pressure above atmospheric. No specific value is required. Differential pressure readings for the control structure indicated that pressure was maintained above atmospheric at the time of this event. On October 24, 2003, surveillance testing successfully demonstrated that the Control Structure HVAC and CREOAS systems were capable of maintaining the control structure habitability envelope at a pressure greater than + 1/8" w.g. As such, there was no loss of safety function. The licensee has notified the NRC Resident Inspector. Notified R1DO (A. Della Greca) |
| ENS 40196 | 24 September 2003 03:20:00 | At 0053 hours on September 24, 2003 with Susquehanna Unit 1 operating at 100% power an automatic reactor scram occurred due to low water level. At the time of the scram, reactor feed pump testing was in progress and the 'C' reactor feed pump tripped. The reactor recirc pumps runback initiated as expected when water level reached 30" with the feed pump tripped. Level continued to drop and reached the Level 3 auto scram setpoint. Level continued to drop and reached a low level of approximately -48" wide range. Reactor Core Isolation Cooling and High Pressure Coolant Injection auto started at their initiation setpoints and injected to the vessel to recover level. All level 2 and 3 containment isolations occurred as expected. The reactor recirc pumps tripped as expected when level 2 was reached. Reactor Pressure was controlled with bypass valves, there were no Safety Relief Valve lifts. There are no challenges to containment. Unit 1 is currently stable in Mode 3 with both reactor recirc pumps restarted. A human performance error was the cause of the reactor feed pump trip. Investigation is continuing into the plant response to the reactor feed pump trip. The NRC Resident Inspector was notified of this event. |