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| {{#Wiki_filter:September 7, 2021 Mr. David P. Rhoades Senior Vice President Exelon Generation Company, LLC President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Rd Warrenville, IL 60555 | | {{#Wiki_filter:}} |
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| ==SUBJECT:==
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| CALVERT CLIFFS NUCLEAR POWER PLANT, UNITS 1 AND 2 - CLOSEOUT OF BULLETIN 2012-01, DESIGN VULNERABILITY IN ELECTRIC POWER SYSTEM (EPID L-2020-PPM-0005)
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| ==Dear Mr. Rhoades:==
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| The purpose of this letter is to inform you that the U.S. Nuclear Regulatory Commission (NRC) staff has verified that Exelon Generation Company, LLC (the licensee) has provided the necessary information requested in NRCs Bulletin (BL) 2012-01, Design Vulnerability in Electric Power System, dated July 27, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12074A115), for Calvert Cliffs Nuclear Power Plant, Units 1 and 2 (Calvert Cliffs). The NRC staff has completed its review of this information and has closed out BL 2012-01 for this facility.
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| The NRC issued BL 2012-01 on July 27, 2012, to all holders of operating licenses and combined licenses for nuclear power reactors, except those who have permanently ceased operation and have certified that fuel has been removed from the reactor vessel. The bulletin requested information about each facilitys electric power system designs that would allow the NRC staff to verify the systems capability to address open phase conditions. Specifically, the NRC requested licensees to provide the following information:
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| A description of how the protection scheme for engineered safety features buses (Class 1E for current operating plants or non-Class 1E for passive plants) is designed to detect and automatically respond to a single-phase open circuit condition or high impedance ground fault condition on offsite power circuits or another power source A description of the operating configuration of engineered safety features buses (Class 1E for current operating plants or non-Class 1E for passive plants) at power (i.e.,
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| normal operating condition)
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| By {{letter dated|date=October 23, 2012|text=letter dated October 23, 2012}} (ADAMS Accession No. ML12299A254), the licensee provided its response to BL 2012-01 for Calvert Cliffs. By {{letter dated|date=January 31, 2014|text=letter dated January 31, 2014}} (ADAMS Accession No. ML14035A456), the license provided supplemental information for this facility in response to an NRC staff request for additional information issued on December 20, 2013 (ADAMS Accession No. ML13351A314).
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| D. Rhoades By letters dated October 9, 2013, and March 16, 2015 (ADAMS Accession Nos. ML13333A147 and ML15075A454, respectively), the Nuclear Energy Institute (NEI) submitted a voluntary industry initiative to address open phase conditions at nuclear power plants. The NEI {{letter dated|date=March 16, 2015|text=letter dated March 16, 2015}}, stated, in part:
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| The initiative is a formal commitment by the companies that operate nuclear power plants to follow a specific policy or plan of action. The initiative calls for a proactive plan and schedule for addressing the potential design vulnerabilities to the open phase condition.
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| To evaluate the adequacy of the open phase isolation systems designs, the NRC staff inspected four nuclear power plants with four distinct open phase isolation system designs using the NRC Temporary Instruction (TI) 2515/194, Inspection of the Licensees Implementation of Industry Initiative Associated with the Open Phase Condition Design Vulnerabilities in Electric Power Systems (NRC Bulletin 2012-01), dated October 31, 2017 (ADAMS Accession No. ML17137A416). A summary of the NRC staffs preliminary observations and issues needing additional clarity were discussed with industry representatives in two public meetings conducted on September 19, 2018, and October 17, 2018. The meeting summaries can be found in ADAMS under Package Accession Nos. ML18268A342 and ML18309A226, respectively.
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| By {{letter dated|date=June 6, 2019|text=letter dated June 6, 2019}} (ADAMS Accession No. ML19163A176), NEI submitted Revision 3 of the voluntary industry initiative to include an option for plants to perform a risk evaluation under certain boundary conditions to support manual response to an open phase condition. NEI also submitted NEI 19-02, Guidance for Assessing Open Phase Condition Implementation Using Risk Insights on June 20, 2019 (ADAMS Accession No. ML19172A086).
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| In July 2021, the NRC staff performed an inspection using TI 2515/194, Revision 3, at Calvert Cliffs to verify the licensees implementation of the voluntary industry initiative at this facility. To address the open phase condition design vulnerability issue at this facility, the licensee implemented open phase isolation system plant modifications that provide detection and alarm in the control room, and necessary plant procedures that allow operators to diagnose and take manual action to mitigate an open phase condition. The NRC inspection report listed below documents the results of this TI 2515/194 inspection:
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| Calvert Cliffs Nuclear Power Plant, Units 1 and 2 - Temporary Instruction 2515/194 Inspection Report 05000317/2021011 and 05000318/2021011, dated July 29, 2021 (ADAMS Accession No. ML21210A124)
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| The NRC staff reviewed the information submitted by the licensee and the results of the TI 2515/194 inspection for Calvert Cliffs. No findings nor exceptions were identified. Based on this review, the NRC staff concludes that the licensee provided the necessary information requested in BL 2012-01 and has completed the implementation of its open phase isolation system. Therefore, the NRC staff has closed BL 2012-01 for Calvert Cliffs.
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| D. Rhoades If you have any questions, please contact me at 301-415-2871 or by email to Michael.Marshall @nrc.gov.
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| Sincerely,
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| /RA/
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| Michael Marshall, Sr. Project Manager Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-317, 50-318 cc: Listserv
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| ML21225A432 *by email OFFICE NRR/DORL/LPL1/PM NRR/DORL/LPL1/LA NRR/DEX/EEEB/BC(A)* NRR/DRA/APOB/BC NAME MMarshall KEntz SRay AZoulis DATE 08/16/2021 08/17/2021 08/13/2021 08/26/2021 OFFICE NRR/DRO/IOEB/BC NRR/DORL/LPL1/BC NRR/DORL/LPL1/PM NAME LRegner JDanna MMarshall DATE 08/20/2021 09/03/2021 09/07/2021}}
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