ML20070L025
| ML20070L025 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 03/10/2020 |
| From: | V Sreenivas Plant Licensing Branch 1 |
| To: | Bryan Hanson Exelon Generation Co |
| Sreenivas V, NRR/DORL/LPL1, 415-2596 | |
| References | |
| EPID L-2020-LLA-0031 | |
| Download: ML20070L025 (10) | |
Text
March 10, 2020 Mr. Bryan C. Hanson Senior Vice President Exelon Generation Company, LLC President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
R. E. GINNA NUCLEAR POWER PLANT - REGULATORY AUDIT IN SUPPORT OF LICENSE AMENDMENT REQUEST TO SUPPORT SHUTDOWN OF REACTOR DURING UPCOMING REFUELING OUTAGE (EPID L-2020-LLA-0031)
Dear Mr. Hanson:
By letter dated February 25, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20056E958), as supplemented by letter dated March 6, 2020 (ADAMS Accession No. ML20066E040), Exelon Generation Company, LLC (the licensee) submitted a license amendment request to revise R. E. Ginna Nuclear Power Plant (Ginna)
Technical Specifications 3.4.7, RCS [Reactor Coolant System] Loops - MODE 5, Loops Filled; 3.4.8, RCS Loops - MODE 5, Loops Not Filled; 3.9.4, Residual Heat Removal (RHR) and Coolant Circulation - Water Level 23 Ft; and 3.9.5, Residual Heat Removal (RHR) and Coolant Circulation - Water Level < 23 Ft, to add an asterisk to allow the use of alternative means for RHR.
To support its safety evaluation, the U.S. Nuclear Regulatory Commission (NRC) staff will conduct an audit at Ginna on March 17-18, 2020. The proposed amendment would allow the use of alternate means of RHR due to the possibility of not being able to open the normal RHR suction valve MOV 700.
The purpose of this regulatory audit is to understand the performance and reliability of the proposed alternate RHR methods. This one-time change is requested to support Ginna in the shutdown of the reactor during the upcoming refueling outage scheduled to start in April 2020.
The audit plan is enclosed.
Within 45 days from the completion of the audit, the NRC staff will issue an audit summary and any formal requests for additional information.
B. Hanson If you have any questions, please contact me at 301-415-2597 or V.Sreenivas@nrc.gov.
Sincerely,
/RA/
V. Sreenivas, Project Manager Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-244
Enclosure:
Regulatory Audit Plan cc: Listserv
REGULATORY AUDIT PLAN FOR MARCH 17-18, 2020 LICENSE AMENDMENT REQUEST EXELON GENERATION COMPANY, LLC R. E. GINNA NUCLEAR POWER PLANT DOCKET NO. 50-244
1.0 BACKGROUND
By letter dated February 25, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20056E958), as supplemented by letter dated March 6, 2020 (ADAMS Accession No. ML20066E040), Exelon Generation Company, LLC (the licensee) submitted to the U.S. Nuclear Regulatory Commission (NRC) a license amendment request to add a one-time note for use of alternate residual heat removal (RHR) methods to the R. E.
Ginna Nuclear Power Plant (Ginna) Technical Specifications. The proposed amendment would allow the use of alternate means of RHR due to the possibility of not being able to open the normal RHR suction valve MOV 700. The purpose of this regulatory audit is to understand the performance and reliability of the proposed alternate RHR methods.
2.0 REGULATORY AUDIT BASIS This regulatory audit is based on the following:
General Design Criterion 34 (RHR) - A system to remove residual heat shall be provided. The system safety function shall be to transfer fission product decay heat and other residual heat from the reactor core at a rate such that specified acceptable fuel design limits and the design conditions of the reactor coolant pressure boundary are not exceeded. Suitable redundancy in components and features, and suitable interconnections, leak detection, and isolation capabilities shall be provided to assure that for onsite electric power system operation (assuming offsite power is not available) and for offsite electric power system operation (assuming onsite power is not available),
the system safety function can be accomplished assuming a single failure.
General Design Criterion 35 (Emergency Core Cooling) - This criterion requires that an emergency core cooling system (ECCS) with the capability for accomplishing abundant emergency core cooling shall be provided. The system safety function shall be to transfer heat from the core following any loss of reactor coolant such that fuel and clad damage that could interfere with continued effective core cooling is prevented, and clad metal-water reaction is limited to negligible amounts.
General Design Criteria 37 (Testing of ECCS) - The ECCS shall be designed to permit appropriate periodic pressure and functional testing to assure (1) the structural and leaktight integrity of its components, (2) the operability and performance of the active components of the system, and (3) the operability of the system as a whole, and under conditions as close to design as practical, the performance of the full operational Enclosure 1
sequence that brings the system into operation, including operation of applicable portions of the protection system; the transfer between normal and emergency power sources; and the operation of the associated cooling water system.
General Design Criterion 54 (Piping Systems Penetrating Containment) - Piping systems penetrating primary reactor containment shall be provided with leak detection, isolation, and containment capabilities having redundancy, reliability, and performance capabilities that reflect the importance to safety of isolating these piping systems. Such piping systems shall be designed with a capability to test periodically the operability of the isolation valves and associated apparatus and to determine if valve leakage is within acceptable limits.
3.0 REGULATORY AUDIT SCOPE The audit team will view supporting analysis, calculations, and documentation associated with use of alternate means of RHR (including cases where offsite power may not be available) due to the possibility of not being able to open the normal RHR suction valve MOV 700. The audit team will meet with subject matter expert(s) to discuss details and to support the NRC staffs understanding of the license amendment request.
4.0 INFORMATION AND OTHER MATERIAL NECESSARY FOR THE REGULATORY AUDIT The NRC staff requests access to any documentation that supports the use of alternate decay heat removal methods (including liquid-to-liquid steam generator operation). This includes analysis, calculations, procedures, and documentation associated with use of alternate means of RHR (including cases where offsite power may not be available). Specific questions are included in Appendix A to this audit plan.
5.0 TEAM ASSIGNMENTS The NRC audit team will consist of:
Robert Beaton, Nuclear Engineer, NRR/DSS/SNSB Josh Borromeo, Acting Chief, NRR/DSS/SNSB Jim Hickey, Senior Level Advisor, NRR/DSS (Remote)
Josh Wilson, Reactor Systems Engineer, NRR/DSS/SNSB (Remote)
Ravi Grover, Safety and Plant Systems Engineer, NRR/DSS/STSB Victor Cusumano, Chief, NRR/DSS/STSB Matt Leech, Risk and Reliability Analyst, NRR/DRA/APOB 6.0 LOGISTICS The audit will take place on March 17-18, 2020, at the Ginna site located at 1503 Lake Rd.,
Ontario, New York. Entrance and exit meetings will be held at the beginning and end of the audit, respectively. A preliminary schedule is included in Appendix B to this audit plan.
7.0 SPECIAL REQUESTS The NRC staff requests the licensee to make identified documents available to the NRC auditors in the eRoom to the extent possible. Use of the eRoom allows multiple auditors in different
geographic locations to examine the same document at the same time, which improves the efficiency and reduces the cost of the audit. Additional documents may be identified as the review progresses. The eRoom should prevent the NRC staff from copying, printing, or in any way retaining the information the licensee makes available in the eRoom. The eRoom should remain open to the NRC staff until March 30, 2020. Please also provide a conference telephone to allow communication with remote participants and internet access.
8.0 DELIVERABLES An audit report will be generated at the completion of the audit. Following the audit, the NRC staff will identify the information that is needed to complete the staffs review and will request that the licensee formally submit the information to the NRC.
Appendix A: Audit Topics Items for the alternate method of filling steam generators (SGs) water solid and using the SGs as water-to-water heat exchangers o Discuss why there is a need to make the SGs water solid in lieu of normal safety-related auxiliary feedwater (AFW) and SG atmospheric relief valves for decay heat removal during the installation of the alternate residual heat removal (RHR) system.
Do both SGs need to be placed into this alternate water solid alignment?
o What is the contingency for being in the alternate water solid SG configuration if a loss-of-offsite power (LOOP) occurs?
Can the SGs be recovered for feeding and steaming and have associated procedures and operating training been developed?
Can the turbine driven auxiliary feedwater pump (TDAFW) be recovered?
Will the main steam supply lines for the TDAFW be filled with water and require additional actions to drain?
Will heat transfer remain effective if reactor coolant pumps are lost due to LOOP?
o Provide more explanation and information on how the SGs and steam lines have been analyzed to be filled with water and remain in allowable stresses.
o Provide more information to explain how water hammer to the SGs and steam lines is addressed. There is operating experience of water hammer events showing that if flow is stopped and then resumed, even in a lower pressure pump application, that water hammer could result, especially when it involves vertical piping draining when the flow is stopped.
o Discuss pressure relief capabilities in SG while water solid.
o Have thermal-hydraulic analyses been performed to support the water solid SG alternate means of cooling?
How will defense in depth be maintained:
o What are the planned compensatory measures and equipment protection (e.g.,
safety-related emergency power (emergency diesel generators), switchyard activities) during times the alternate systems are in use?
o How will non-safety equipment be identified and protected? Are any compensatory actions going to be in place to ensure required systems are protected?
Provide a detailed sequence of events or timeline of how the alternate cooling systems will be placed in service.
Enclosure 2
Decay heat:
o The license amendment request supplement stated that the licensee expects to initiate the water solid SG cooldown at approximately 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> post-shutdown.
What are the risks and recovery actions if the water solid method does not work as expected?
Are there procedures to mitigate a leak or rupture of the temporary RHR modified loop?
Equipment hatch:
o Are there plans on placing any restrictions on use of the equipment hatch while these alternative cooling systems are in service?
The submittal appears to have contradictory information on an important aspect regarding the SG alternate cooling mode. On page 11 of Attachment 1 to the license amendment request, when answering the question, Does the proposed amendment create the possibility of a new or different kind of accident from any previously evaluated? the response is No. However, on page 4 of Attachment 1, it states, As part of the proposed alternate alignments, steam line water hammer was evaluated as a potentially different kind of event from that previously evaluated. Please discuss.
Items related to the alternate RHR systems:
o Provide analysis and calculations related to the thermal-hydraulic performance of the alternate means of RHR (including cases where offsite power may not be available).
o What is the basis for the 10 percent opening of MOV 700 for the second alternative RHR mode? Explain how the RHR system will operate if the valve is stuck open more than 10 percent.
o How will the emergency core cooling system (ECCS) operate in the case of a loss-of-coolant accident (LOCA) while using alternate RHR? What is the low-pressure flow path?
o Describe any differences in the LOCA response if the ECCS is into the hot leg vs. the cold leg. Is reverse flow expected through the core at any point in time?
o Describe the procedures and controls that have been developed to ensure the alternate RHR piping has a means to be filled and vented.
o What pressure is the alternate RHR temporary piping designed to? Have potential pressure transients been anticipated?
o In case the alternate method becomes inoperable, would the licensee be able to take applicable technical specification required actions specified in the limiting conditions for operation (LCOs), including the LCOs 3.9.4 and 3.9.5 action to Close all containment penetrations providing direct access from containment atmosphere to outside atmosphere within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />?
o What would be the status of the alternate method after its one-time use?
Items related to MOV 700:
o Discuss any information regarding MOV 700 reliability and operational history.
o Section 5.4.5.3.4 of the Ginna Updated Final Safety Analysis Report lists several alternate means of core decay heat removal in the event valve MOV 700 fails.
Were these alternate means considered?
What if the refurbished valve does not work? Would the alternate RHR system be required to continue operation after the its proposed expiration date of June 30, 2020?
Appendix B: Proposed Schedule March 17, 2020 8:30 a.m. - Audit entrance 9:00 a.m. to 4:30 p.m. - Technical discussion (see Appendix A, Audit Topics) 4:30 p.m. - Audit exit March 18, 2020 8:30 a.m. - Audit entrance 9:00 a.m. to 12:00 p.m. - Technical discussion (see Appendix A, Audit Topics) 1:00 p.m. to 4:30 p.m. - Issue closeout 4:30 p.m. - Audit exit Note: This is a preliminary schedule and subject to change.
Enclosure 3
ML20070L025 *by e-mail OFFICE NRR/DORL/LPL1/PM NRR/DORL/LPL1/LA NRR/DSS/SNSB/BC(A)* NRR/DSS/STSB/BC NAME VSreenivas LRonewicz JBorromeo VCusumano DATE 03/10/2020 03/10/2020 03/10/2020 03/10/2020 OFFICE NRR/DRA/APOB/BC NRR/DORL/LPL1/BC NRR/DORL/LPL1/PM NAME AZoulis JDanna VSreenivas DATE 03/10/2020 03/10/2020 03/10/2020