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 3

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

ML15044A033
Person / Time
Site:	Oconee
Issue date:	02/09/2015
From:	Batson S Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
ONS-2014-159
Download: ML15044A033 (7)

Text

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.

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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 ifthe 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 ifthe 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).

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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.