11-27-2017 | On September 13, 2017, with the Davis-Besse Nuclear Power Station operating at approximately 100 percent power, Auxiliary Feed Water ( AFW) Pump Turbine 1 experienced high inboard bearing temperature during performance of quarterly Surveillance Testing. The turbine was tripped, and disassembly revealed damage to the journal bearing. The bearirig was replaced, and following successful post maintenance testing, AFW Train 1 was declared Operable on September 16. The cause of the bearing damage was an improperly marked oil sight glass, which allowed operation with improper bearing lubrication. The improper markings were due to the maintenance work instruction for replacing the sight glass not including dimensions or guidance for setting required operational bands.
On September 26, 2017, it was identified that low inboard bearing oil level had likely existed since completion of the previous quarterly surveillance test on June 21, when an oil sample was taken following testing but the bearing was not refilled due to the improperly marked sight glass. This issue is being reported in accordance with 10 CFR 50.73(a)(2)(v)(B) as a condition that could have prevented the fulfillment of the safety function, and in accordance with 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by Technical Specifications. |
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Category:Letter
MONTHYEARML24281A0662024-10-0404 October 2024 EN 57363 - MPR Associates, Inc. Report in Accordance with 10 CFR Part 21 on Incomplete Dedication of Contactors Supplied as Basic Components IR 05000346/20244032024-09-27027 September 2024 Security Baseline Inspection Report 05000346/2024403 ML24269A0552024-09-25025 September 2024 Submittal of the Updated Final Safety Analysis Report, Revision 35 05000346/LER-2021-001-01, Emergency Diesel Generator Speed Switch Failure Due to Direct Current System Ground2024-09-19019 September 2024 Emergency Diesel Generator Speed Switch Failure Due to Direct Current System Ground ML24134A1522024-09-17017 September 2024 Exemption from the Requirements of 10 CFR 50.71(e)(4) Final Safety Analysis Report Update Schedule (EPID L-2024-LLE-0005) - Letter ML24260A2382024-09-16016 September 2024 Notification of an NRC Biennial Licensed Operator Requalification Program Inspection and Request for Information ML24255A8032024-09-11011 September 2024 Technical Specification 5.6.6 Steam Generator Tube Inspection 180-Day Report ML24255A8642024-09-0606 September 2024 Rscc Wire & Cable LLC Dba Marmon Industrial Energy & Infrastructure - Part 21 Retraction of Final Notification ML24249A1602024-09-0505 September 2024 Information Request to Support Upcoming Material Control and Accounting Inspection at Davis-Besse Nuclear Power Station L-24-188, Submittal of Quality Assurance Program Manual, Revision 302024-08-27027 August 2024 Submittal of Quality Assurance Program Manual, Revision 30 ML24239A3972024-08-23023 August 2024 Rssc Wire & Cable LLC Dba Marmon - Part 21 Final Notification - 57243-EN 57243 IR 05000346/20240052024-08-22022 August 2024 Updated Inspection Plan for Davis-Besse Nuclear Power Station (Report 05000346/2024005) L-24-186, Response to RAI for Exemption Request from 10 CFR 50.71(e)(4) Final Safety Analysis Update Schedule2024-08-15015 August 2024 Response to RAI for Exemption Request from 10 CFR 50.71(e)(4) Final Safety Analysis Update Schedule IR 05000346/20240022024-08-0101 August 2024 Integrated Inspection Report 05000346/2024002 IR 05000346/20244012024-07-30030 July 2024 Security Baseline Inspection Report 05000346/2024401 ML24208A0962024-07-25025 July 2024 57243-EN 57243 - Rssc Wire & Cable LLC, Dba Marmon - Part 21 Notification L-24-032, Cycle 23 and Refueling Outage 23 Inservice Inspection Summary Report2024-07-15015 July 2024 Cycle 23 and Refueling Outage 23 Inservice Inspection Summary Report L-24-063, License Amendment Request to Remove the Table of Contents from the Technical Specifications2024-07-0808 July 2024 License Amendment Request to Remove the Table of Contents from the Technical Specifications L-24-024, Annual 10 CFR 50.46 Report of Changes to or Errors in Emergency Core Cooling System Evaluation Models2024-06-19019 June 2024 Annual 10 CFR 50.46 Report of Changes to or Errors in Emergency Core Cooling System Evaluation Models L-23-214, Submittal of Relief Request for Impractical American Society of Mechanical Engineers Boiler and Pressure Vessel Code Section XI Examination Requirements2024-06-0505 June 2024 Submittal of Relief Request for Impractical American Society of Mechanical Engineers Boiler and Pressure Vessel Code Section XI Examination Requirements L-24-019, Unit No.1 - Report of Facility Changes, Tests, and Experiments2024-05-22022 May 2024 Unit No.1 - Report of Facility Changes, Tests, and Experiments ML24142A3532024-05-21021 May 2024 Station—Information Request to Support the NRC Annual Baseline Emergency Action Level and Emergency Plan Changes Inspection L-24-111, Response to Regulatory Issue Summary 2024-01, Preparation and Scheduling of Operator Licensing Examinations2024-05-15015 May 2024 Response to Regulatory Issue Summary 2024-01, Preparation and Scheduling of Operator Licensing Examinations L-24-072, Combined Annual Radiological Environmental Operating Report and Radioactive Effluent Release Report - 20232024-05-15015 May 2024 Combined Annual Radiological Environmental Operating Report and Radioactive Effluent Release Report - 2023 L-24-031, Unit No.1 - Steam Generator Tube Circumferential Crack Report - Spring 2024 Refueling Outage2024-05-14014 May 2024 Unit No.1 - Steam Generator Tube Circumferential Crack Report - Spring 2024 Refueling Outage IR 05000346/20240012024-05-0303 May 2024 Integrated Inspection Report 05000346/2024001 L-24-069, Occupational Radiation Exposure Report for Year 20232024-04-30030 April 2024 Occupational Radiation Exposure Report for Year 2023 L-24-018, Submittal of Core Operating Limits Report, Cycle 24, Revision 02024-04-16016 April 2024 Submittal of Core Operating Limits Report, Cycle 24, Revision 0 ML24089A2582024-04-0101 April 2024 Request for Information for the NRC Quuadrennial Comprehensive Engineering Team Inspection: Inspection Report 05000346/2024010 L-24-013, Annual Notification of Property Insurance Coverage2024-03-26026 March 2024 Annual Notification of Property Insurance Coverage ML24036A3472024-03-0707 March 2024 Exemption from Select Requirements of 10 CFR Part 73 (EPID L-2023-LLE-0076 (Security Notifications, Reports, and Recordkeeping and Suspicious Activity Reporting)) ML24057A0752024-03-0101 March 2024 the Associated Independent Spent Fuel Storage Installations IR 05000346/20230062024-02-28028 February 2024 Re-Issue Annual Assessment Letter for Davis-Besse Nuclear Power Station (Report 05000346/2023006) ML24057A3362024-02-28028 February 2024 Annual Assessment Letter for Davis-Besse Nuclear Power Station (Report 05000346/2023006) L-23-264, Request for Exemption from 10 CFR 50.71(e)(4) Final Safety Analysis Report Update Schedule2024-02-23023 February 2024 Request for Exemption from 10 CFR 50.71(e)(4) Final Safety Analysis Report Update Schedule CP-202300502, Notice of Planned Closing of Transaction and Provision of Documents to Satisfy Order Conditions2024-02-23023 February 2024 Notice of Planned Closing of Transaction and Provision of Documents to Satisfy Order Conditions L-24-050, Retrospective Premium Guarantee2024-02-22022 February 2024 Retrospective Premium Guarantee IR 05000346/20243012024-02-0202 February 2024 NRC Initial License Examination Report 05000346/2024301 IR 05000346/20230042024-01-31031 January 2024 Integrated Inspection Report 05000346/2023004 ML23313A1352024-01-17017 January 2024 Authorization and Safety Evaluation for Alternative Request RP 5 for the Fifth 10 Year Interval Inservice Testing Program ML23353A1192023-12-19019 December 2023 Operator Licensing Examination Approval Davis Besse Nuclear Power Station, January 2024 L-23-260, Corrections to the 2022 Combined Annual Radiological Environmental Operating Report and Radioactive Effluent Release Report for the Davis-Besse Nuclear Power Station2023-12-0707 December 2023 Corrections to the 2022 Combined Annual Radiological Environmental Operating Report and Radioactive Effluent Release Report for the Davis-Besse Nuclear Power Station ML23338A3172023-12-0606 December 2023 Notification of NRC Baseline Inspection and Request for Information; Inspection Report 05000346/2024001 L-23-243, Independent Spent Fuel Storage Installation - Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation2023-12-0606 December 2023 Independent Spent Fuel Storage Installation - Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation IR 05000346/20234032023-11-0202 November 2023 Security Baseline Inspection Report 05000346/2023403 ML23293A0612023-11-0101 November 2023 Letter to the Honorable Marcy Kaptur, from Chair Hanson Responds to Letter Regarding Follow Up on Concerns Raised by Union Representatives During the June Visit to the Davis-Besse Nuclear Power Plant ML24045A0322023-10-26026 October 2023 L-23-221 Proposed Exam Submittal Cover Letter L-23-215, Changes to Emergency Plan2023-10-19019 October 2023 Changes to Emergency Plan ML23237B4222023-09-28028 September 2023 Energy Harbor Nuclear Corp. - Vistra Operations Company LLC - Letter Regarding Order Approving Transfer of Licenses and Draft Conforming License Amendments ML23269A1242023-09-27027 September 2023 Request for Withholding Information from Public Disclosure 2024-09-06
[Table view] Category:Licensee Event Report (LER)
MONTHYEAR05000346/LER-2021-001-01, Emergency Diesel Generator Speed Switch Failure Due to Direct Current System Ground2024-09-19019 September 2024 Emergency Diesel Generator Speed Switch Failure Due to Direct Current System Ground 05000346/LER-2017-0022017-11-27027 November 2017 Auxiliary Feed Water Pump Turbine Bearing Damaged due to Improperly Marked Lubricating Oil Sight Glass, LER 17-002-00 For Davis-Besse Nuclear Power Station, Unit 1, Regarding Auxiliary Feed Water Pump Turbine Bearing Damaged due to Improperly Marked Lubricating Oil Sight Glass 05000346/LER-2017-0012017-09-18018 September 2017 Emergency Diesel Generator Fuel Oil Storage Tank Vents Not Adequately Protected from Tornado-Generated Missiles, LER 17-001-00 for Davis-Besse, Unit 1, Regarding Emergency Diesel Generator Fuel Oil Storage Tank Vents Not Adequately Protected from Tornado-Generated Missiles 05000346/LER-2016-0082017-02-27027 February 2017 Application of Technical Specification for the Safety Features Actuation System Instrumentation, LER 16-008-01 for Davis-Besse Nuclear Power Station Unit 1 Regarding Application of Technical Specification for the Safety Features Actuation System Instrumentation 05000346/LER-2016-0092016-11-0909 November 2016 Reactor Trip due to Rainwater Intrusion and Auxiliary Feedwater Actuation on High Steam Generator Level, LER 16-009-00 for Davis-Besse Nuclear Power Station, Unit 1 Regarding Reactor Trip due to Rainwater Intrusion and Auxiliary Feedwater Actuation on High Steam Generator Level 05000346/LER-2016-0072016-08-22022 August 2016 Pressurizer Code Safety Valve Setpoint Test Failures, LER 16-007-00 for Davis-Besse, Unit 1 Regarding Pressurizer Code Safety Valve Setpoint Test Failures 05000346/LER-2016-0062016-08-15015 August 2016 Potential to Trip Emergency Diesel Generator on High Crankcase Pressure, LER 16-006-00 for Davis-Besse Nuclear Power Station Unit 1 RE: Potential to Trip Emergency Diesel Generator on High Crankcase Pressure 05000346/LER-2016-0052016-07-11011 July 2016 - , Plant Startup with Anticipatory Reactor Trip System in Main Turbine Bypass, LER 16-005-00 for Davis-Besse, Unit 1, Regarding Plant Startup with Anticipatory Reactor Trip System in Main Turbine Bypass 05000346/LER-2016-0042016-06-0606 June 2016 Reactor Coolant System Hot Leg Resistance Temperature Detector Wire Insulation Degradation, LER 16-004-00 for Davis-Besse Nuclear Power Station, Unit 1 Regarding Reactor Coolant System Hot Leg Resistance Temperature Detector Wire Insulation Degradation 05000346/LER-2016-0032016-05-31031 May 2016 Leak from Reactor Coolant Pump Seal Piping Flexible Hose due to Undetected Manufacture Weld Defect, LER 16-003-00 for Davis-Besse Nuclear Power Station, Unit 1 Regarding Leak from Reactor Coolant Pump Seal Piping Flexible Hose due to Undetected Manufacture Weld Defect 05000346/LER-2016-0022016-03-29029 March 2016 Unanticipated Steam and Feedwater Rupture Control System Actuation, LER 16-002-00 for Davis-Besse Nuclear Power Station, Unit 1, Regarding Unanticipated Steam and Feedwater Rupture Control System Actuation 05000346/LER-2016-0012016-03-29029 March 2016 1 OF 7, LER 16-001-00 for Davis-Besse Nuclear Power Station Unit 1 Regarding Reactor Trip During Nuclear Instrumentation Calibrations and Steam Feedwater Rupture Control System Actuation on High Steam Generator Level ML0409003422004-03-26026 March 2004 LER 97-004-01 for Davis-Besse, Unit 1 Regarding Reactor Coolant Pump Motor Oil Piping Not Protected from Leakage as Required Per 10CFR50, Appendix R ML0404901932004-02-13013 February 2004 LER 99-003-01 for Davis-Besse, Unit 1 Regarding Failure to Perform Engineering Evaluation for Pressurizer Cooldown Rate Exceeding Technical Specification Limit ML0331701982003-11-0707 November 2003 LER 98-002-01 for Davis-Besse Unit 1 Regarding Plant Trip Due to High Pressurizer Level as a Result of Loss of Letdown Capability 2024-09-19
[Table view] |
comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
Energy Industry Identification System (EIIS) codes are identified in the text as [XX].
System Description:
The Davis-Besse Nuclear Power Station (DBNPS) Emergency Feedwater (EFW) System [BA] consists of two Auxiliary Feedwater (AFW) trains and the Motor Driven Feedwater Pump (MDFP) [BA-P]. The AFW System provides a safety-related source of feedwater to the secondary side of the Steam Generators [AB-SG] in the event of a loss of normal feedwater flow to remove reactor decay heat. The AFW pumps [BA-P] take suction from the condensate storage tanks [KA-T] and pump to the Steam Generator secondary side through the AFW nozzles. The Steam Generators function as a heat sink for core decay heat. The heat load is dissipated by releasing steam to the atmosphere from the Steam Generators via the Main Steam Safety Valves [SB-RV] or Atmospheric Vent Valves [SB-VTV].
The AFW System consists of two steam turbine driven AFW pumps, each of which provides a nominal 100% capacity. The steam turbine driven AFW pumps receive steam from either of the two main steam headers, upstream of the main steam isolation valves. The AFW System supplies water via two headers, each capable of feeding either steam generator. The 100% capacity is sufficient to remove decay heat and cool the unit to Decay Heat Removal System [BP] entry conditions. The AFW System normally receives a supply of water from the Condensate Storage Tanks. A safety grade source of water is also supplied by the Service Water System [B1].
The MDFP train provides feedwater to the steam generators during normal plant startup and shutdown. The non-safety related MDFP train is also designed to provide a backup supply of feedwater to the steam generators in the event of a total loss of both AFW and main feedwater.
Technical Specifications:
Technical Specification (TS) Limiting Condition for Operation (LCO) 3.7.5 requires three EFW trains be Operable in Modes 1 through 3, and in Mode 4 when a Steam Generator is relied upon for heat removal. In Mode 1 with one EFW train inoperable for reasons other than an inoperable steam supply, LCO 3.7.5 Condition B requires the inoperable EFW train be restored to Operable status in 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. If these actions and associated completion times cannot be met, or if two EFW trains are inoperable, then LCO 3.7.5 Condition D requires the plant be placed in Mode 3 in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Mode 4 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
DESCRIPTION OF EVENT:
On September 13, 2017, AFW Train 1 was declared inoperable at 1007 hours0.0117 days <br />0.28 hours <br />0.00167 weeks <br />3.831635e-4 months <br /> to perform scheduled quarterly Surveillance Testing to meet TS Surveillance Requirement 3.7.5.2. At 1044 hours0.0121 days <br />0.29 hours <br />0.00173 weeks <br />3.97242e-4 months <br /> AFW Pump 1 was started, and at 1120 the pump achieved full flow (at least 600 gallons per minute) through the flow test line. Shortly after achieving full pump flow, the turbine inboard bearing temperature began to rapidly increase, and exceeded the bearing metal temperature computer alarm setpoint of 220 degrees F at 1126 hours0.013 days <br />0.313 hours <br />0.00186 weeks <br />4.28443e-4 months <br />. After the operating crew investigated the possibility of a faulted temperature instrument, the turbine was tripped locally at 1155 hours0.0134 days <br />0.321 hours <br />0.00191 weeks <br />4.394775e-4 months <br />. The inboard turbine bearing oil was then sampled, which showed discoloration indicative of bearing degradation. The journal bearing was then disassembled to reveal damage to the journal bearing.
The bearing was replaced, and following successful post maintenance testing, AFW Train 1 was declared Operable on September 16, 2017, at 0540 hours0.00625 days <br />0.15 hours <br />8.928571e-4 weeks <br />2.0547e-4 months <br />.
comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required, to respond to, the information collection.
CAUSE OF EVENT:
The direct cause of the damaged AFW Pump Turbine 1 inboard bearing was due to operation with insufficient lubrication oil. The AFW Pump Turbine journal bearings are lubricated by slinger rings that ride on the turbine shaft located within the bearing assembly. During operation, the slinger rings rotate on the turbine shaft and rotate through the oil contained in the oil reservoir sump. The oil adheres to the slinger ring surfaces and is deposited on the turbine shaft near the bearing as the shaft rotates to provide bearing lubrication. During investigation and disassembly of the damaged inboard bearing, it was identified the existing oil level in the bearing was below the vendor recommended level, but was within the marked acceptable band of the oil level sight glass. The AFW Pump Turbine 1 inboard bearing oil sight glass operational band was marked too low to ensure proper bearing lubrication.
The root cause of the damaged AFW Pump Turbine 1 inboard bearing was that the preventive maintenance work instruction for replacing the sight glass did not include dimensions or guidance for setting required operational bands, and did not contain a requirement to reference the vendor manual to ensure the appropriate operational bands are established. The lack of detail in the work instruction resulted in Maintenance personnel setting the sight glass narrow operational band (minimum and maximum acceptable levels) via skill-of-the-craft when replacing the inboard bearing oil level sight glass.
ANALYSIS OF EVENT:
During investigation into the reasons for the damaged AFW Pump Turbine 1 inboard bearing, it was identified on September 26, 2017, that low inboard bearing oil level had likely existed since completion of the previous quarterly surveillance test on June 21, 2017. Bearing oil samples are taken routinely following the quarterly surveillance test for analysis, and the investigation revealed the inboard bearing was not refilled after sampling on June 21, 2017, because the inboard bearing oil level was within the acceptable band indicated on the sight glass.
A risk assessment was performed for the approximately 86 days AFW Pump Turbine 1 was unavailable until the bearing was repaired on September 15, 2017. The assessment considered there was reasonable assurance AFW Train 1 would have successfully completed the first total hour of operation, but may have failed sometime during the latter 23 hours2.662037e-4 days <br />0.00639 hours <br />3.80291e-5 weeks <br />8.7515e-6 months <br /> of the 24-hour Probabilistic Risk Assessment (PRA) mission time.
The plant risk associated with the extended unavailability for AFW Train 1 was determined to be very low, with a delta Core Damage Frequency (CDF) of 7.90E-07 and a delta Large Early Release Frequency (LERF) of 2.22E-08 for internal events. A sensitivity study to include the impact of a common cause failure was performed, resulting in a delta CDF of 8.09E-07, which is still below the threshold to be considered very low plant risk. However, when qualitatively evaluated for External Events (Seismic, Fire), this event is overall considered to be of low safety significance. Additional evaluation of the ability of AFW Pump Turbine 1 to continue to operate for the required mission time in the as-found condition is ongoing, and results of this evaluation will be provided in a supplement to this report.
Reportability Discussion:
Because AFW Train 1 was inoperable for approximately 87 days with the plant operating in Mode 1, and Technical Specification 3.7.5 allows operation to continue only for 3 days for this condition, this issue represents a condition prohibited by the plant's Technical Specifications, which is reportable in accordance comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
05000 - 346
3. LER NUMBER
002 00 2017 Reportability Discussion: (Continued) with 10 CFR 50.73(a)(2)(i)(B). This Licensee Event Report is being submitted 60 days from the discovery of this reportable issue on September 26, 2017, in accordance with 10 CFR 50.73(a)(1) and 10 CFR 50.4(a)).
Additionally, during the time AFW Train 1 was inoperable, AFW Train 2 was inoperable for maintenance and testing on multiple occasions. Therefore, this issue is also reportable as an event or condition that could have prevented fulfillment of a safety function of system needed to remove residual heat per 10 CFR 50.73(a)(2)(v)(B). At the time of the AFW Train 1 bearing damage on September 13, 2017, AFW Train 2 was Operable; therefore, no loss of safety function existed at the time of discovery, and no immediate notification to the NRC per 10 CFR 50.72 was required.
CORRECTIVE ACTIONS:
Completed Actions:
AFW Pump Turbine 1 inboard bearing was replaced, and following successful post maintenance testing, declared Operable on September 16, 2017, at 0540 hours0.00625 days <br />0.15 hours <br />8.928571e-4 weeks <br />2.0547e-4 months <br />. As part of this maintenance work, the AFW Pump Turbine 1 inboard bearing oil level sight glass minimum and maximum dimensions were properly marked based on slinger ring submergence in accordance with the turbine vendor manual.
The AFW Pump Turbine 2 inboard bearing sight glass minimum and maximum dimensions have been verified to be consistent with the as-left AFW Pump Turbine 1 inboard bearing dimensions, and the AFW Pump Turbine 1 and 2 outboard bearing sight glasses have been re-marked to the appropriate levels based on measurements made external to the bearing.
The Lubrication Manual Data Sheets for the AFW Pump Turbines have been revised to include bearing oil sight glass minimum and maximum level dimensions, and the AFW Pump Turbine Preventive Maintenance Activities have been revised to reference the Lubrication Manual for marking the minimum and maximum dimensions on the bearing oil sight glasses.
Scheduled Actions:
The AFW Pump Turbine outboard bearing sight glass level markings will be verified to be correct by direct observation of one turbine's oil slinger rings submergence.
For Safety-Related and critical equipment, the basis for oil sight glass markings will be validated and captured in the Lubrication Manual, and field sight glass markings will be verified to be in accordance with the information captured in the Lubrication Manual. Additionally, Preventive Maintenance Activities that implement sight glass replacements for Safety-Related and critical equipment will be revised as necessary to include guidance to mark the new sight glass in accordance with the Lubrication Manual.
PREVIOUS SIMILAR EVENTS:
There have been no Licensee Event Reports (LERs) at the DBNPS in the past three years related to inoperability of the Auxiliary Feedwater System or low bearing oil level.
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05000346/LER-2017-001 | Emergency Diesel Generator Fuel Oil Storage Tank Vents Not Adequately Protected from Tornado-Generated Missiles LER 17-001-00 for Davis-Besse, Unit 1, Regarding Emergency Diesel Generator Fuel Oil Storage Tank Vents Not Adequately Protected from Tornado-Generated Missiles | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000346/LER-2017-002 | Auxiliary Feed Water Pump Turbine Bearing Damaged due to Improperly Marked Lubricating Oil Sight Glass LER 17-002-00 For Davis-Besse Nuclear Power Station, Unit 1, Regarding Auxiliary Feed Water Pump Turbine Bearing Damaged due to Improperly Marked Lubricating Oil Sight Glass | 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
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