Semantic search
| Discovered date | Reporting criterion | Title | Description | LER | |
|---|---|---|---|---|---|
| ENS 42919 | 19 October 2006 13:21:00 | 10 CFR 26.73, Applicability | Non-Licensed Supervisor Failed Follow-Up Testing | A non-licensed employee supervisor had a confirmed positive test for alcohol during a follow up fitness for duty test. The employee's access to the plant has been put on administrative hold, and the individual has been escorted offsite. The NRC Resident Inspector was notified of this by the licensee. Contact the Headquarter Operations Officer for further details. | |
| ENS 42527 | 25 April 2006 17:30:00 | 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | Unanalyzed Condition - Control Logic Error | TMI Issue Report # 482679 identified an issue while performing reviews of fire abnormal operating procedures to assure compliance with the Fire Hazards Analysis Report (FHAR), in that a control logic error was identified in the circuitry elementary drawing for the isolation valves DH-V-6A and DH-V-6B between the Borated Water Storage Tank (BWST) and the Reactor Building (RB) sump. Plant circuitry was verified to be wired as per the elementary drawing. This circuitry design was to prevent a hot short, due to a fire, from opening the valve. However, the identified control logic error could allow a spurious opening to occur on DH-V-6A or DH-V-6B due to a fire. The FHAR credits these valves as being protected from spuriously opening due to a fire in AB-FZ-5 (Auxiliary Building 281' general area). If this protection is not provided, then spurious opening could result in draining the BWST inventory to the RB sump. This hot short condition would result in the depletion of the BWST inventory and loss of the High Pressure Injection (HPI) makeup capability, resulting in an unanalyzed condition that significantly degrades plant safety. This condition is reportable under 10 CFR 50.72(b)(3)(ii)(B), 'Any event or condition that results in the nuclear power plant being in an unanalyzed condition that significantly degrades plant safety.' A 60-day LER is also required under 10 CFR 50.73(a)(2)(ii)(B) for the same degraded condition. An hourly fire-watch has been established in the affected fire zone in the 281' elevation Auxiliary Building as an interim compensatory measure. Additionally, the control circuitry at the 1A and 1B ES MCCs will be modified to prevent the RB sump isolation valves DH-V-6A and DH-V-6B from spuriously opening due to a hot short. The licensee notified the NRC Resident Inspector. | |
| ENS 42475 | 5 April 2006 12:04:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Both Trains of High Pressure Injection (Hpi) Declared Inoperable Due to Potential Air Binding of Pumps | TMI declared both High Pressure Injection Trains not operable due to air void in the suction line from the Sodium Hydroxide tank. The postulated issued is that in the event of a small break LOCA where the plant would need to go on HPI piggy back Ops (the Low Pressure Injection supplying suction to the High Pressure Injection pumps) the air could cause the HPI pumps to become air bound. The Plant entered a shutdown Tech Spec 3.0.1 at 0804 (EDT) and exited the timeclock at 0850 (EDT) when the Sodium Hydroxide tank was isolated, thus isolating the air void from the ECCS (Emergency Core Cooling System) pumps. The licensee is continuing their investigation into root cause and operability. The licensee will inform the NRC Resident Inspector. * * * RETRACTION FROM A. MILLER TO P. SNYDER AT 1301 EDT ON 6/2/06 * * * The purpose of this call is to retract the notification (Event Number 42475) made by TMI Unit 1, Docket No. 50-289 / License No. DPR-50. On April 5, 2006, at 1408 hours, the Shift Manager made a notification (Event Number 42475) to the NRC Operations Center in accordance with 10 CFR 50.72 (b)(3)(v)(D) (i.e. any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident). The event was reported as 'Both trains of High Pressure Injection (HPI) Declared Inoperable due to potential air binding of Pumps.' On April 5, 2006, air voids were found in the NaOH tank piping, upstream of the HPI pumps, and the Shift Manager conservatively declared both trains of HPI inoperable due to the air voids. This placed TMI-1 in a 1-hour shutdown Limiting Condition for Operation (LCO). The isolation valves for the NaOH tank line piping were then Closed to eliminate the possibility that the voids could be transported to the HPI pumps. The HPI pumps were then declared operable and TMI-1 entered a 72-hour shutdown LCO. During the 72-hour LCO, the air bubble was vented from the system. An initial extent of condition evaluation was completed and an event response team was established. Numerical Applications, Inc. (NAI) was retained to perform GOTHIC Model run on the two phase flow conditions and determine the percent air density of the water at the suction to the Low Pressure Injection (LPI) pumps and the HPI pumps. The NAI analysis concluded that the densities of air found at the suction of the LPI and HPI pumps were below the safe operating level as stated by the pump manufacturers. Based on the results of the evaluation, TMI-1 has determined that the LPI and HPI pumps were operable. Past operability of these pumps with the maximum size air bubble found is affirmed. Therefore, this event does not meet the 10 CFR 50.72 or 10 CFR 50.73 reporting criteria and the notification for Event Number 42475 is retracted. The resident inspector has been notified. Notified R1DO (T. Jackson). | |
| ENS 42416 | 14 March 2006 14:30:00 | 10 CFR 26.73, Applicability | Licensed Sro Failed Random Fitness for Duty Test | A licensed employee supervisor had a confirmed positive for alcohol during a random fitness-for-duty test. The employee's access to the plant has been put on administrative hold, and the individual has been escorted offsite. Contact the Headquarters Operations Officer for additional details. The licensee has informed the NRC Resident Inspector. * * * * UPDATE ON 3/14/06 AT 1534 FROM S. BRANTLEY TO P. SNYDER * * * * The licensee will be issuing a press release on this event. The licensee has informed the NRC Resident Inspector. | |
| ENS 42413 | 13 March 2006 16:10:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Ventilation Fan Inoperable | The Technical Support Center ventilation system was discovered to be non-functional at 1110 on March 13, 2006. The cause of the ventilation problem was determined to be damaged drive belts on the supply fan. The belts were replaced and the ventilation system supply fan was returned to service at 1253 on March 13, 2006. This condition is considered a Loss of Offsite Response Capability and is therefore reportable under 10CFR50.72(b)(3)(xiii). A corrective action request has been generated to follow remedial action. The licensee notified the NRC Resident Inspector. | |
| ENS 42406 | 11 March 2006 06:00:00 | 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | Unit Entered a T.S. Required Shutdown After Declaring Both Condenser Offgas Radiation Monitors Inoperable | Condenser offgas radiation monitor flow was blocked. Both Offgas Radiation Monitors were affected and out of service. We entered T.S. 3.0.1 - When a Limiting Condition for Operation is not met, within 1 hour action shall be initiated to place the unit in a condition in which the specification does not apply: 1. Hot Standby within 6 hours. 2. Hot Shutdown with following 6 hours. 3. Cold Shutdown with subsequent 24 hours. We started to shutdown the Unit at 0100 (hours) on 11 March 2006. Removed blockage from condenser offgas radiation monitors common exhaust and evaluated operability of the condenser offgas radiation monitors. At 0315 (hours) on 11 March 2006, we returned RM-A-5 and RM-A-15 (Condenser Offgas Radiation Monitors) to service and exited T.S. 3.0.1. We stopped the power reduction at 0251 (hours) on 11 March 2006 while performing the evaluation on the condenser offgas radiation monitors. We stopped the power reduction at 73% reactor power. We started power escalation to 100% at 0338 (hours) on 11 March 2006. The blockage was discovered at 2125 hours on 3/10/2006 during rounds by Secondary Plant Operator who noted that the normal 1 SCFM exhaust flow was reading zero flow. During troubleshooting to discover the cause of the blockage, a bluish foreign material was found in the common exhaust piping. An investigation is underway to identify the source of the foreign material. The licensee informed the NRC Resident Inspector. | |
| ENS 41663 | 3 May 2005 17:10:00 | 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | Appendix R Fire Scenario Involving Multiple High Impedance Faults | TMI Issue Report # 329440 identifies an issue associated with a previously unidentified/unanalyzed Appendix R fire scenario involving multiple high impedance faults. An engineering evaluation has determined that certain safety related power circuits are not protected against multiple high impedance faults, which in combination with a fire in the 305' elevation of the Control Building, could cause a loss of safe shutdown functions from the control room and the remote shutdown panel. An hourly fire-watch has been established in the affected fire zone in the 305' elevation of the Control Building as an interim compensatory measure. The NRC Resident Inspector will be notified. | |
| ENS 41444 | 16 February 2005 01:55:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | Possible Failure to Meet Design Basis Requirements of Positive Pressure in the Control Tower Envelope Following a Design Basis Accident. | The licensee provided the following information: During operator rounds it was discovered that a double door for the control tower habitability envelope was propped open (from painting earlier in the day). This condition would have resulted in not meeting the design basis requirements of maintaining a positive pressure inside the control tower envelope following a design basis accident. The doors were immediately closed. An issue report was generated and a prompt investigation was commenced in accordance with station policies. The NRC resident Inspector was notified.
The licensee provided the following information: An ENS notification (EN# 41444) was made at approximately 00:59 on 2/20/2005 regarding a potentially unanalyzed condition associated with a double door for the Control Tower Habitability Envelope, which was propped open. It was initially thought that this condition could have resulted in not meeting the design basis requirements for the Control Tower Envelope. However, an analysis of an air flow measurement across the open door has shown that the unfiltered air in-leakage into the Control Tower Habitability Envelop would not exceed the value assumed in the design basis accident analysis for Control Room Habitability. Since this event did not result in an unanalyzed condition, this event is being retracted. The licensee notified NRC Resident Inspector. | |
| ENS 40296 | 4 November 2003 19:30:00 | 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | Pressurizer Heater Bundle Diaphragm Plate Degraded Condition | On November 4, 2003, during the TMI Unit 1 15th (T1R15) refueling outage, an inspection of the Pressurizer Heater Bundle (PHB) Diaphragm Plate was completed. This Inspection identified a leak path emanating from the lower Pressurizer Heater Bundle. The initial indication of a potential Reactor Coolant System (RCS) leak was boric acid residue located between the PHB Diaphragm Plate and the PHB Cover Plate. Initially the leak was believed to be from a seal weld, which is considered comparable to a gasket leak. Following disassembly of the PHB Cover Plate and performance of NDE, it was determined that the pathway was through the edge of the PHB Diaphragm Plate. This degraded condition of the PHB Diaphragm Plate is indicative of a RCS pressure boundary leak. This notification is being made in accordance with 10 CFR 50.72(b)(3)(ii)(A)." The licensee provided the following pre-refuel outage information: RCS Leak Rate = less than 0.1 gallons per minute Activity = 0.45 microcuries/milliliter TS (Technical Specifications) Limits: No leakage (3.1.6.4) Secondary System Activity = less than 1E-10 microcuries/milliliter The licensee has notified the NRC Resident Inspector. * * * UPDATE ON 11/24/03 AT 0114 EST FROM JOHN SCHORK TO HOWIE CROUCH * * * Subsequent to the initial report made on 11/4/03, the Pressurizer Heater Bundle (PHB) Diaphragm Plate was repaired. On November 23, 2003 during performance of post-maintenance testing inspections with the plant in Hot Shutdown, steam was observed emanating from either the seal weld or the PHB diaphragm plate. This update is being made to EN 40296 because the observed leak is being conservatively classified as a leak from the Primary System Pressure Boundary and is being addressed in a manner consistent with TMI Technical Specifications 3.1.6.4 and 3.1.6.6. An evaluation of the safety implications of the leak has been initiated. A condition report has been generated to capture all of the actions that have been and will be taken in response to the leak. The plant is being taken to cold shutdown in order to perform an inspection and repair of the leak. The plant continues to be subcritical with all control rods fully inserted and the Reactor Coolant System boron concentration is at the refueling boron concentration. The plant continues to remain in the T1R15 refueling outage. The NRC TMI-1 Sr. Resident Inspector has been notified of the leak. No other notifications were made to the State, Local or other governmental agencies. No press release has been issued regarding the event. The cause and corrective action to repair the leak will be addressed in the licensee event report being submitted in response to EN 40296. The location of the leak observed on November 23, 2003 is in the immediate vicinity of the lower Pressurizer Heater Bundle. There has been no determination of the volumetric leak rate. The leak consists (of) steam wisping from the location. The start date of the leak is November 23, 2003 and the leak was initially observed during hot shutdown checks at 1930 hours on November 23, 2003. There has been no radiological release to the environment as a result of this leak. The licensee has notified the NRC Senior Resident Inspector. Notified R1DO (John Rogge) and NRR (William Ruland). | 05000289/LER-2003-003 |
| ENS 40244 | 13 October 2003 15:20:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification to Osha at Three Mile Island Regarding a Fatality | A contract delivery employee apparently suffered a heart attack while making a delivery at TMI. The contract employee was treated by the site EMTs and transported to the Hershey Medical Center by off site medical assistance. AmerGen was notified at approximately 1315 that the contract employee was declared dead at the Hershey Medical Center. AmerGen notified OSHA as required for a fatality at the facility. The NRC resident was notified. | |
| ENS 40178 | 19 September 2003 06:24:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Emergency Siren Capability Due to Adverse Weather Conditions | TMI is notifying the NRC Operations Center in accordance with 10 CFR 50.72 (b)(2)(xi), Notification of Other Government Agency and 10 CFR 50.72 (b)(3)(xiii) Major Loss of Emergency Preparedness Capabilities. At 0224 AM on Friday, September 19 it was determined that 25 of 79 of the public emergency sirens for Three Mile Island Unit 1 were inoperable due to loss of power due to Tropical Storm Isabel. Subsequently, it has been determined that 32 of 79 of the sirens are inoperable. The inoperable sirens are located throughout the five risk counties around TMI. The inoperability of the sirens around TMI impacts a large segment of the population. Contingency actions have been established for the deficient sirens. Automatic route alerting, that is the coordinated use of vehicles that will make loudspeaker announcements throughout affected areas will be utilized if the need should arise prior to restoration of power to the inoperable sirens. Local power company line crews have been notified of the loss of power to the sirens and are working to restore power on a priority basis to the sirens. The licensee informed the affected counties/PEMA and the NRC Resident Inspector. | |
| ENS 40121 | 29 August 2003 19:05:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Degradation of Emergency Preparedness Response Capabilities | At 1505 hrs. on Friday August 29, 2003, TMI Unit 1 determined that there had been a degradation of the emergency preparedness response capabilities when there was a loss of the Emergency Notification System (ENS), the Health Physics Network (HPN) and the Emergency Response Data System (ERDS). In addition most site telephone lines were inoperable. The loss of these communications systems was most probably caused by a lightning strike. Limited telephonic communications remains with the TMI 1 control room, i.e., one commercial phone exchange, a satellite phone and the emergency management phone circuit remain operable. TMI 1 has verified operability of the ERO notification system (pagers), and the communication circuit used to notify the state and local counties. The siren system for local counties was unaffected by loss of site telephone systems. Plant page and radio systems remain operable. Adequate communications capabilities are operable at this time to implement the emergency plan. Repairs to restore the inoperable telephone systems are in progress at this time. A return to service time for all systems is to be determined. However, at the time of this report, the ENS line has been restored to an operable status. TMI 1 has determined that this event is reportable to the NRC as an 8-hour non-emergency report in accordance with 10 CFR 50.72 (b)(3)(xiii). The NRC Resident Inspector, the State of Pennsylvania, and local authorities have been notified by the licensee.
The licensee reported that the Emergency Notification System (ENS) was restored to service on 8/29/03 at approximately 2100 hours EDT and the Emergency Response Data System (ERDS) was returned to service on 8/29/03 at 2212 hours EDT. Notified R1DO (James Trapp). |