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Category:Letter type:ONS
MONTHYEARONS-2018-025, 2017 Annual Radiological Environmental Operating Report (AREOR)2018-05-15015 May 2018 2017 Annual Radiological Environmental Operating Report (AREOR) ONS-2018-024, 2017 Annual Radioactive Effluent Release Report (ARERR)2018-04-30030 April 2018 2017 Annual Radioactive Effluent Release Report (ARERR) ONS-2018-032, Ufsar/Selected Licensee Commitment Changes2018-04-17017 April 2018 Ufsar/Selected Licensee Commitment Changes ONS-2018-029, Technical Specifications Task Force (TSTF) - 448, Revision 3, Control Room Habitability, License Amendment Request No. 2015-03, Supplement 32018-04-0404 April 2018 Technical Specifications Task Force (TSTF) - 448, Revision 3, Control Room Habitability, License Amendment Request No. 2015-03, Supplement 3 ONS-2018-027, Oconee, Units 1, 2, and 3, Submittal of Emergency Plan Revision 2018-0022018-03-28028 March 2018 Oconee, Units 1, 2, and 3, Submittal of Emergency Plan Revision 2018-002 ONS-2018-023, Response to Nrc'S Request for Additional Information Regarding Relief Request 17-ON-001; Alternative to Extend the Code Case N-770, Inspection Item B, Examination Frequency2018-03-20020 March 2018 Response to Nrc'S Request for Additional Information Regarding Relief Request 17-ON-001; Alternative to Extend the Code Case N-770, Inspection Item B, Examination Frequency ONS-2018-017, Oconee, Units 1, 2, and 3, Submittal of Revised Evaluation to Emergency Plan2018-03-15015 March 2018 Oconee, Units 1, 2, and 3, Submittal of Revised Evaluation to Emergency Plan ONS-2018-021, ISFSI - Submittal of 2017 Annual Effluent Release Report2018-03-0101 March 2018 ISFSI - Submittal of 2017 Annual Effluent Release Report ONS-2018-020, Refuel 28 (O2R28) In-service Inspection (ISI) and Steam Generator In-service Inspection (SG-ISI) Report, Fifth 10-Year ISI Interval2018-02-26026 February 2018 Refuel 28 (O2R28) In-service Inspection (ISI) and Steam Generator In-service Inspection (SG-ISI) Report, Fifth 10-Year ISI Interval ONS-2018-013, Technical Specification Bases Changes2018-02-22022 February 2018 Technical Specification Bases Changes ONS-2018-015, Duke Energy Response to Request for Additional Information; Request for Alternative to Codes and Standards Requirements Pursuant to 10 CFR 50.55a(z) to Satisfy 10 CFR 50.55a(h)(2) Associated with Bronze Tape Wrapped Emergency Power Cabl2018-02-19019 February 2018 Duke Energy Response to Request for Additional Information; Request for Alternative to Codes and Standards Requirements Pursuant to 10 CFR 50.55a(z) to Satisfy 10 CFR 50.55a(h)(2) Associated with Bronze Tape Wrapped Emergency Power Cables i ONS-2018-014, License Amendment Request (LAR) for Changes to the Duke Energy Physical Security Plan - License Amendment Request No. 2018-012018-02-12012 February 2018 License Amendment Request (LAR) for Changes to the Duke Energy Physical Security Plan - License Amendment Request No. 2018-01 ONS-2018-019, Submittal of Emergency Plan, Section B2018-02-0505 February 2018 Submittal of Emergency Plan, Section B ONS-2018-011, Ufsar/Selected Licensee Commitment Changes2018-01-25025 January 2018 Ufsar/Selected Licensee Commitment Changes ONS-2017-087, Spent Fuel Pool Evaluation Supplemental Report, Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from ...2017-12-0404 December 2017 Spent Fuel Pool Evaluation Supplemental Report, Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from ... ONS-2017-083, Core Operating Limits Report (COLR) for Cycle 29 ONEl-0400-491, Revision 02017-11-21021 November 2017 Core Operating Limits Report (COLR) for Cycle 29 ONEl-0400-491, Revision 0 ONS-2017-041, Revision to Tornado/Helb Mitigation Strategies and Regulatory Commitments2017-11-15015 November 2017 Revision to Tornado/Helb Mitigation Strategies and Regulatory Commitments ONS-2017-085, Duke Energy Comments on the October 24, 2017, Public Meeting with NRC Committee to Review Generic Requirements (CRGR)2017-11-15015 November 2017 Duke Energy Comments on the October 24, 2017, Public Meeting with NRC Committee to Review Generic Requirements (CRGR) ONS-2017-079, Supplemental Information to Support NRC Review of Relief Request No. 17-0N-001; Alternative to Extend the Code Case N-770, Inspection Item B Examination Frequency2017-11-13013 November 2017 Supplemental Information to Support NRC Review of Relief Request No. 17-0N-001; Alternative to Extend the Code Case N-770, Inspection Item B Examination Frequency ONS-2017-078, Emergency Plan Revision 2017-0042017-11-0909 November 2017 Emergency Plan Revision 2017-004 ONS-2017-074, Proposed Amendment to the Renewed Facility Operating Licenses Regarding Revisions to the Updated Final Safety Analysis Report Section Associated with Tile Standby Shutdown Facility License Amendment Request No. 2017-032017-10-20020 October 2017 Proposed Amendment to the Renewed Facility Operating Licenses Regarding Revisions to the Updated Final Safety Analysis Report Section Associated with Tile Standby Shutdown Facility License Amendment Request No. 2017-03 ONS-2017-067, Response to Request for Additional Information Regarding License Amendment Request for TSTF-448, Revision 3, Control Room Habitability, License Amendment Request No. 2015-03, Supplement 22017-10-16016 October 2017 Response to Request for Additional Information Regarding License Amendment Request for TSTF-448, Revision 3, Control Room Habitability, License Amendment Request No. 2015-03, Supplement 2 ONS-2017-069, (ONS) - Additional Information Regarding License Amendment Request for Temporary Completion Time for One Keowee Hydro Unit Inoperable for Generator Stator Replacement2017-10-13013 October 2017 (ONS) - Additional Information Regarding License Amendment Request for Temporary Completion Time for One Keowee Hydro Unit Inoperable for Generator Stator Replacement ONS-2017-070, Transmittal of Oconee, Units 1, 2, and 3, Emergency Plan Implementing Procedures Manual Volume 2, Revision 2017-0022017-10-0505 October 2017 Transmittal of Oconee, Units 1, 2, and 3, Emergency Plan Implementing Procedures Manual Volume 2, Revision 2017-002 ONS-2017-072, Fifth Ten Year Lnservice Inspection Interval, Relief Request No. 17-0N-001; Alternative to Extend the Code Case N-770, Inspection Item B Examination Frequency2017-10-0303 October 2017 Fifth Ten Year Lnservice Inspection Interval, Relief Request No. 17-0N-001; Alternative to Extend the Code Case N-770, Inspection Item B Examination Frequency ONS-2017-066, Registration for Use of General License Spent Fuel Cask Numbers 147 and 1482017-09-20020 September 2017 Registration for Use of General License Spent Fuel Cask Numbers 147 and 148 ONS-2017-061, Revised Response to NRC Regulatory Issue Summary 2017-03, Preparation and Scheduling of Operator License Examinations2017-08-10010 August 2017 Revised Response to NRC Regulatory Issue Summary 2017-03, Preparation and Scheduling of Operator License Examinations ONS-2017-060, Registration for Use of General License Spent Fuel Cask Numbers 145 and 1462017-08-0303 August 2017 Registration for Use of General License Spent Fuel Cask Numbers 145 and 146 ONS-2017-059, Transmittal of Response to March 12, 2012 Request for Information, Recommendation 2.1 Flooding, Required Response 3, Flooding Focused Evaluation Summary2017-07-31031 July 2017 Transmittal of Response to March 12, 2012 Request for Information, Recommendation 2.1 Flooding, Required Response 3, Flooding Focused Evaluation Summary ONS-2017-050, Technical Specification Bases Change 2017-042017-07-21021 July 2017 Technical Specification Bases Change 2017-04 ONS-2017-052, Technical Specification Bases Change 2017-032017-07-20020 July 2017 Technical Specification Bases Change 2017-03 ONS-2017-043, Technical Specification Bases Change 2017-012017-07-20020 July 2017 Technical Specification Bases Change 2017-01 ONS-2017-047, Registration for Use of General License Spent Fuel Cask Numbers 142, 143, and 1442017-06-27027 June 2017 Registration for Use of General License Spent Fuel Cask Numbers 142, 143, and 144 ONS-2017-042, Additional Information Regarding License Amendment Request for Temporary Completion Time for One Keowee Hydro Unit Inoperable for Generator Stator Replacement, License Amendment Request No. 2015-08, Supplement 22017-06-0101 June 2017 Additional Information Regarding License Amendment Request for Temporary Completion Time for One Keowee Hydro Unit Inoperable for Generator Stator Replacement, License Amendment Request No. 2015-08, Supplement 2 ONS-2017-040, Transmittal of Emergency Plan Implementing Procedures Manual Volume 1, Revision 2017-0032017-05-22022 May 2017 Transmittal of Emergency Plan Implementing Procedures Manual Volume 1, Revision 2017-003 ONS-2017-037, 2016 Annual Radiological Environmental Operating Report2017-05-15015 May 2017 2016 Annual Radiological Environmental Operating Report ONS-2017-026, Submittal of Ufsar/Selected Licensee Commitment Change2017-04-11011 April 2017 Submittal of Ufsar/Selected Licensee Commitment Change ONS-2017-024, Revision 028 to ERTG-001, Emergency Response Organization and Emergency Services Training Program2017-03-16016 March 2017 Revision 028 to ERTG-001, Emergency Response Organization and Emergency Services Training Program ONS-2017-001, Submittal of Emergency Plan Program Procedure HP/O/B/1009/001 Rev 0452017-03-0202 March 2017 Submittal of Emergency Plan Program Procedure HP/O/B/1009/001 Rev 045 ONS-2017-017, Emergency Plan Implementing Procedures Manual Volume 1, Revision 2017-0012017-03-0202 March 2017 Emergency Plan Implementing Procedures Manual Volume 1, Revision 2017-001 ONS-2017-018, Emergency Plan Implementing Procedures Manual Volume 2, Revision 2017-0012017-03-0202 March 2017 Emergency Plan Implementing Procedures Manual Volume 2, Revision 2017-001 ONS-2017-015, End of Cycle 29 (1 EOC29) Refueling Outage Lnservice Inspection (ISI) and Steam Generator Lnservice Inspection (SG-ISI) Report, Fifth 10-Year ISI Interval2017-02-24024 February 2017 End of Cycle 29 (1 EOC29) Refueling Outage Lnservice Inspection (ISI) and Steam Generator Lnservice Inspection (SG-ISI) Report, Fifth 10-Year ISI Interval ONS-2017-019, Technical Specification Bases Change 2015-092017-02-23023 February 2017 Technical Specification Bases Change 2015-09 ONS-2017-011, Emergency Plan Revised Evaluation2017-02-0202 February 2017 Emergency Plan Revised Evaluation ONS-2017-009, Units 1, 2 & 3 - Notification of Compliance with Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond Design Basis External Events.2017-02-0101 February 2017 Units 1, 2 & 3 - Notification of Compliance with Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond Design Basis External Events. ONS-2017-004, Submittal of Core Operating Limits Report2017-01-12012 January 2017 Submittal of Core Operating Limits Report ONS-2017-006, Emergency Plan Revision 2016-0032017-01-12012 January 2017 Emergency Plan Revision 2016-003 ONS-2016-097, Emergency Plan/Emergency Plan Implementing Procedures Manual, Revised 10CFR 50.54(q) Evaluation(S)2016-11-17017 November 2016 Emergency Plan/Emergency Plan Implementing Procedures Manual, Revised 10CFR 50.54(q) Evaluation(S) ONS-2016-098, Special Report Per Technical Specification 5.6.6, Inoperability of Post Accident Monitoring Containment High Range Radiation Monitors2016-11-14014 November 2016 Special Report Per Technical Specification 5.6.6, Inoperability of Post Accident Monitoring Containment High Range Radiation Monitors ONS-2016-096, Revised Response to NRC Regulatory Issue Summary 2015-05, Preparation and Scheduling of Operator Licensing Examinations2016-11-10010 November 2016 Revised Response to NRC Regulatory Issue Summary 2015-05, Preparation and Scheduling of Operator Licensing Examinations 2018-05-15
[Table view] Category:Licensee 30-Day Written Event Report
MONTHYEARRA-18-129, Technical Specification 5.6.6 Special Report, Inoperability of Post Accident Monitoring Instrument; Containment Sump Wide Range Water Level (CR 02218964)2018-08-23023 August 2018 Technical Specification 5.6.6 Special Report, Inoperability of Post Accident Monitoring Instrument; Containment Sump Wide Range Water Level (CR 02218964) ONS-2016-098, Special Report Per Technical Specification 5.6.6, Inoperability of Post Accident Monitoring Containment High Range Radiation Monitors2016-11-14014 November 2016 Special Report Per Technical Specification 5.6.6, Inoperability of Post Accident Monitoring Containment High Range Radiation Monitors ONS-2015-085, Special Report in Accordance with Selected Licensee Commitment (SLC) 16.7.4, Hydrogen Analyzers2015-07-10010 July 2015 Special Report in Accordance with Selected Licensee Commitment (SLC) 16.7.4, Hydrogen Analyzers ONS-2014-159, Special Report Per Selected Licensee Commitment 16.9.9 Auxiliary Service Water (Asw) System and Main Steam Atmospheric Dump Valves and Oconee Transition from the Station Asw System to Protected Service Water System - Revision 32015-02-0909 February 2015 Special Report Per Selected Licensee Commitment 16.9.9 Auxiliary Service Water (Asw) System and Main Steam Atmospheric Dump Valves and Oconee Transition from the Station Asw System to Protected Service Water System - Revision 3 RA-14-0032, CFR 50.46 - 30-Day Report for Estimated Impacts to Peak Cladding Temperature Due to Fuel Pellet Thermal Conductivity Degradation2014-12-17017 December 2014 CFR 50.46 - 30-Day Report for Estimated Impacts to Peak Cladding Temperature Due to Fuel Pellet Thermal Conductivity Degradation ML12073A3542012-03-0909 March 2012 30-Day Report Pursuant to 10 CFR 50.46, Changes to or Errors in an Evaluation Model ML11347A1932011-12-0808 December 2011 Day Report Pursuant to 10 CFR 50.46, Changes to or Errors in an Evaluation Model ML1007005562010-03-0303 March 2010 LER, Oconee, Units 1, 2, & 3, Submittal of 30-Day Report Pursuant to Ground Water Protection Initiative and Ground Water Monitoring Wells GM-7R and GM-7DR ML0823208842008-08-13013 August 2008 Site, Independent Spent Fuel Storage Instillation (ISFSI) General License Cask Certificate of Compliance, 30-Day Report Due to Higher Canister Heat Loading ML0517304632005-06-13013 June 2005 Steam Generator Inservice Inspection lEOC22, Steam Generator Tube Plugging and Repair 30-day Report ML0509703152005-03-31031 March 2005 Special Report Per Technical Specification 5.6.6 Problem Investigation Process No.: 0-05-1567, 0-05-1401 2018-08-23
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SCOTT L. BATSON DU KE Vice President Oconee Nuclear Station ENERGY.Duke Energy ONO I VP / 7800 Rochester -Hw" Seneca, SC 29672 ONS-201 4-159 864-873-3274 864-873-4208 fax Special Report Scott.Batson@duke-energy.com February 9, 2015 U.S. Nuclear Regulatory Commission Attention:
Document Control Desk Washington, DC 20555
Subject:
Oconee Nuclear Station Docket Nos. 50-269, -270, -287 Special Report per Selected Licensee Commitment 16.9.9 Auxiliary Service Water (ASW) System and Main Steam Atmospheric Dump Valves and Oconee Transition from the Station ASW System to the Protected Service Water System -Revision 3
Reference:
- 1. Letter from the Nuclear Regulatory Commission to Scott Batson, "Notice of Violation and Confirmatory Order Related to a Fire Protection Program License Condition (Oconee Nuclear Station, Units 1, 2, and 3)," ADAMS Accession No. ML13114A941, dated July 1, 2013.2. Letter from Scott Batson to the Nuclear Regulatory Commission, "Special Report per Selected Licensee Commitment 16.9.9 Auxiliary Service Water (ASW) System and Main Steam Atmospheric Dump Valves and Oconee Transition from the Station ASW System to the Protected Service Water System," ADAMS Accession No. ML14234A095, dated August 15, 2014.3. Letter from Scott Batson to the Nuclear Regulatory Commission, "Special Report per Selected Licensee Commitment 16.9.9 Auxiliary Service Water (ASW) System and Main Steam Atmospheric Dump Valves and Oconee Transition from the Station ASW System to the Protected Service Water System -Revision I ," ADAMS Accession No.ML14280A481, dated October 2, 2014.4. Letter from Scott Batson to the Nuclear Regulatory Commission, "Special Report per Selected Licensee Commitment 16.9.9 Auxiliary Service Water (ASW) System and Main Steam Atmospheric Dump Valves and Oconee Transition from the Station ASW System to the Protected Service Water System -Revision 2," dated November 12, 2014.In accordance with Selected Licensee Commitment (SLC) 16.9.9, please find attached, revision 3 of the special report that describes the plans and procedures that will be used after the turnover of the Protected Service Water (PSW) System to Operations for service following its replacement of the Station Auxiliary Service Water (ASW) System. The report has been revised to discuss the PSW system status following turnover to Operations and risk mitigation actions that will remain in place until the system is declared functional in accordance with the revised SLC.r,(~
U.S. Nuclear Regulatory Commission February 9, 2015 Page 2 A revised SLC 16.9.9 has been implemented to address PSW system capabilities.
The revised SLC will establish the minimum requirements for functionality, conditions and required actions, and implement periodic surveillance testing for the installed portions of the PSW system. PSW Technical Specifications will be implemented after startup from each unit's refueling outage following completion of PSW Modifications and after all of the PSW system equipment installed has been tested. The SLC will be revised at that time to remove any requirements associated with the PSW system that are addressed by the Technical Specifications.
No new NRC commitments are contained in this report. The assessment and management of risk following the transition to PSW ensures that this activity is considered to be of no significance with respect to the health and safety of the public.If there are any questions, please contact Timothy D. Brown, PSW Licensing Manager, at (864) 873-3952.Sincerely, Scott L. Batson Site Vice President Oconee Nuclear Station Attachment U. S. Nuclear Regulatory Commission February 9, 2015 Page 3 CC: Mr. Victor M. McCree, Administrator, Region II U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, GA 30303-1257 Mr. Eddy Crowe NRC Senior Resident Inspector Oconee Nuclear Station Mr. James R. Hall, Project Manager (by electronic mail only)U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation 11555 Rockville Pike Rockville, MD 20852 Mr. Jeffrey A. Whited, Project Manager (by electronic mail only)U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation 11555 Rockville Pike Rockville, MD 20852 ATTACHMENT Oconee Transition to the Protected Service Water System -Revision 3 Special Report ONS Transition to the PSW System -Revision 3 Page 1 of 3 Special Report Oconee Transition To the Protected Service Water System -Revision 3 Purpose and Background SLC 16.9.9 has been revised to reflect the implemented portions of the PSW System. The revised SLC establishes the minimum requirements for functionality, conditions and required actions, and implements periodic surveillance testing for the PSW system. Note that the conditions and required actions remain the same as those provided by the previous SLC. These are described under the Selected Licensee Commitments section of this report.During implementation of activities associated with PSW, it was recognized that activities to seismically qualify PSW switchgear transformers CT-6 and CT-7 have not been completed.
Activities to seismically qualify the transformers are underway and are scheduled to be completed spring of 2015.The mechanical portions of the PSW System have been installed, tested, and are turned over to Operations.
Note that Unit l's flow testing to the Steam Generator's has been completed while Units 2 and 3 will not occur until each unit's next scheduled refueling outage. The turnover of the PSW mechanical system was provided to Operations on January 30, 2015. While the PSW System will be capable and operational, PSW system functionality cannot be established until the PSW switchgear transformers have been seismically qualified; thereby, requiring the ONS Units to maintain entry in Conditions A and C of the revised SLC.In accordance with revised SLC 16.9.9, Protected Service Water (PSW) System, this report updates and outlines the plans and procedures that ONS will use to monitor the capabilities of the portion of the PSW system that has been implemented and mitigate the risk associated with the non-seismic qualification of the PSW switchgear transformers.
System Description
Protected Service Water System The PSW system is designed as a standby system for use under emergency conditions.
The PSW system provides additional "defense in-depth" protection by serving as a backup to existing safety systems and as such, the system is not required to comply with single failure criteria.
The PSW system is provided as an alternate means to achieve and maintain safe shutdown conditions for one, two or three units following certain postulated scenarios.
The PSW system reduces fire risk by providing a diverse power supply to power safe shutdown equipment in accordance with NFPA 805 safe shutdown analyses.
The PSW system requires manual activation in the control room and can be activated if emergency systems are unavailable.
The PSW system provides a diverse means to achieve and maintain safe shutdown by providing secondary side Decay Heat Removal (DHR), Reactor Coolant System (RCS) pump seal cooling, RCS primary inventory control, and RCS boration for reactivity management following plant scenarios that disable the 4160V essential electrical power distribution system. Following achieving safe shutdown, a plant cooldown is initiated within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of event initiation.
PSW is not an Engineered Safety Features Actuation System (ESFAS) and is not credited to mitigate Special Report ONS Transition to the PSW System -Revision 3 Page 2 of 3 design basis events as analyzed in Updated Final Safety Analysis Report (UFSAR) Chapters 6 and 15.Core DHR is provided by feeding the steam generators from the PSW pumps (booster and high head pumps) via PSW flow control valves. Core reactivity is controlled in a safe manner by injecting borated water from the borated water storage tank (BWST) into the RCS to maintain adequate shutdown margin. RCS inventory control is provided by existing plant equipment that can be selectively powered from the PSW Electrical Distribution system.For complete details associated with the PSW system, see the Safety Evaluation for Amendment Nos. 386, 388, and 387 dated August 13, 2014.Selected Licensee Commitments Condition A of revised Selected Licensee Commitment (SLC) 16.9.9 allows the PSW system to be non-functional for 30 days if the Standby Shutdown Facility (SSF) ASW system is operable.Condition B of revised SLC 16.9.9 allows the PSW system to be non-functional while the SSF ASW system is inoperable for a period of 7 days.Condition C of revised SLC 16.9.9 states if the required actions and associated completion times are not met within the specified time periods, then a report is to be written and submitted to the Nuclear Regulatory Commission (NRC) within 30 days outlining plans and procedures to be used to provide for the loss of the system.Conditions A and C of revised SLC 16.9.9 are applicable and entry in these conditions will be maintained until the PSW switchgear transformers are seismically qualified.
PSW Transition Contingencies to mitigate the risk for having the Station ASW system out of service greater than the allowed outage time provided in the original SLC 16.9.9 Condition A were incorporated into a Complex Activity Plan. The Complex Activity Plan was originally reviewed and approved by the Plant Operations Review Committee on July 30, 2014 and then revised, reviewed and approved again by ONS Management on November 6, 2014.The original SLC 16.9.9, Condition A was entered on August 13, 2014, when Station ASW was removed from service. During the period when the SLC was not explicitly applicable to Station ASW, the Complex Activity Plan provided control and risk mitigation during the interim period while transitioning from Station ASW to PSW.The work evolution with exception for the seismic qualification of transformers CT-6 and CT-7 was completed and the mechanical portion of the PSW system was conditionally turned over to Operations on January 30, 2015. The Complex Activity Plan contingencies were terminated and revised SLC 16.9.9 was also implemented on January 30, 2015.Although the PSW system is non-functional, it is operational and capable of providing an alternate means to achieve and maintain safe shutdown conditions for one, two or three units following certain postulated scenarios.
Special Report ONS Transition to the PSW System -Revision 3 Page 3 of 3 The PSW System provides mitigation for events outside of those analyzed in Chapter 15 of the UFSAR: certain high energy line breaks, tornado, loss of lake, and fire. None of the associated events assume a seismic event occurs simultaneously.
The current Probabilistic Risk Assessment seismic model does not contain the PSW System, but since it provides the same functions as the station ASW, the seismic impact of having the Station ASW pump unavailable was evaluated and the following risk management actions were determined to be necessary:
- 1. Protect the SSF.a. If SSF is unavailable for planned maintenance or for unplanned reasons, protect the following systems: i. Emergency Feedwater System (Motor Driven Emergency Feedwater Pumps and Turbine Driven Emergency Feedwater Pumps).Conclusion:
Revised SLC 16.9.9 establishes functionality for the PSW system. It has the same conditions and required actions as the previous SLC. Functionality of the PSW system cannot be established due to the lack of seismic qualification of the PSW switchgear transformers, so it is still necessary to maintain entry in SLC Conditions A and C. The transformers are scheduled to be seismically qualified and PSW declared functional spring of 2015. Appropriate risk management actions are being implemented within Oconee's Maintenance Rule a(4) program to provide for any loss of the system and assure the availability of diverse accident mitigation systems throughout the entire duration.
It is important to note that the benefits of having the system operational and capable even though non-functional improves availability and reliability of the affected systems and equipment.