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MONTHYEARML1016900932010-06-10010 June 2010 Tornado Mitigation License Amendment Request - Response to Request for Additional Information Project stage: Response to RAI ML1021102942010-07-28028 July 2010 ISFSI, McGuire Units 1 & 2, Catawba Units 1 & 2, Quality Assurance Program Topical Report Alternate Amendment 37 Project stage: Request ML1022802302010-08-17017 August 2010 Issuance of Amendments Regarding Evaluation of Amendment 37 of Topical Report on Quality Assurance Program (TAC Nos. ME3387. Project stage: Approval ML14015A1382014-01-13013 January 2014 License Amendment Request: Add Technical Specification for Atmospheric Dump Valves Project stage: Request ML14058A1262014-02-26026 February 2014 NRR E-mail Capture - Acceptance Review Results Regarding Atmospheric Dump Valves License Amendment Request Project stage: Acceptance Review ML14237A0692014-09-17017 September 2014 Request for Additional Information Regarding Atmospheric Dump Valves License Amendment Request Project stage: RAI ML14309A7172014-11-0303 November 2014 Response to Request for Additional Information Regarding Atmospheric Dump Valves License Amendment Request Project stage: Response to RAI ML15027A1442015-02-0202 February 2015 Request for Additional Information Regarding Atmospheric Dump Valves License Amendment Request Project stage: RAI ML15035A5482015-02-0202 February 2015 Supplemental Information - Atmospheric Dumb Valves License Amendment Request Project stage: Supplement ML15065A0302015-03-0303 March 2015 Request for Additional Information Regarding Atmospheric Dump Valves License Amendment Request Project stage: Request ML15090A1922015-03-27027 March 2015 Supplemental Information - Atmospheric Dump Valves License Amendment Request Project stage: Supplement ML15034A1102015-04-15015 April 2015 Request for Withholding Information from Public Disclosure (Tac Nos. MF3388 and M3389) Project stage: Withholding Request Acceptance ML15133A1442015-07-23023 July 2015 Amendment Regarding New Technical Specification 3.7.18 for Atmospheric Dump Valves Project stage: Acceptance Review 2014-02-26
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Category:Letter
MONTHYEARIR 05000317/20230042024-02-0101 February 2024 Integrated Inspection Report 05000317/2023004 and 05000318/2023004 ML24029A0102024-01-29029 January 2024 Request for Information and Notification of Conduct of IP 71111.21.N.04, Age-Related Degradation, Reference Inspection Report 05000317/2024010 and 05000318/2024010 ML24003A8872024-01-19019 January 2024 Exemption from Select Requirements of 10 CFR Part 73 (EPID L-2023-LLE-0033 (Security Notifications, Reports, and Recordkeeping and Suspicious Activity Reporting)) 05000318/LER-2023-004, Submittal of LER 2023-004-00 for Calvert Cliffs Nuclear Power Plant, Unit 2, Submittal of Automatic Reactor Trip from Reactor Protection System Actuation Due to Loss of Unit Service Transformer2024-01-16016 January 2024 Submittal of LER 2023-004-00 for Calvert Cliffs Nuclear Power Plant, Unit 2, Submittal of Automatic Reactor Trip from Reactor Protection System Actuation Due to Loss of Unit Service Transformer ML24011A0732024-01-11011 January 2024 Proposed Alternative to the Requirements for Repair/Replacement of Saltwater (SW) System Buried Piping 05000318/LER-2023-002, Forward LER 2023-002-00 for Calvert Cliffs Nuclear Power Plant, Unit 2, Automatic Reactor Trip from Reactor Protection System Actuation Due to Loss of Unit Service Transformer2024-01-0808 January 2024 Forward LER 2023-002-00 for Calvert Cliffs Nuclear Power Plant, Unit 2, Automatic Reactor Trip from Reactor Protection System Actuation Due to Loss of Unit Service Transformer 05000318/LER-2023-003, Forward LER 2023-003-00 for Calvert Cliffs Nuclear Power Plant, Unit 2, Manual Actuation of Auxiliary Feedwater System Due to 22 Steam Generator Feedwater Pump Trip2024-01-0808 January 2024 Forward LER 2023-003-00 for Calvert Cliffs Nuclear Power Plant, Unit 2, Manual Actuation of Auxiliary Feedwater System Due to 22 Steam Generator Feedwater Pump Trip ML24005A0222024-01-0505 January 2024 Revised Steam Generator Tube Inspection Reports ML23304A0642024-01-0202 January 2024 Issuance of Amendment No. 349 to Modify the Long-Term Coupon Surveillance Program RS-23-125, Request for Exemption from 10 CFR 2.109(b)2023-12-0707 December 2023 Request for Exemption from 10 CFR 2.109(b) ML23331A2992023-11-27027 November 2023 Submittal of Condition Prohibited by Technical Specifications Due to Failure to Sample Diesel Generator Fuel Oil Storage Tank IR 05000317/20230102023-11-20020 November 2023 Biennial Problem Identification and Resolution Inspection Report 05000317/2023010 and 05000318/2023010 ML23318A4722023-11-14014 November 2023 Supplement to License Amendment Request to Adopt TSTF-59-A ML23317A1032023-11-10010 November 2023 Supplemental Information Letter for Part 73 Exemption Request - Responses to Request for Confirmatory Information ML23317A1192023-11-10010 November 2023 Constellation Energy Generation, LLC - 2023 Annual Report - Guarantees of Payment of Deferred Premiums ML23310A0442023-11-0707 November 2023 Project Manager Assignment IR 05000317/20230402023-11-0202 November 2023 95001 Supplemental Inspection Report 05000317/2023040 and Follow-Up Assessment Letter IR 05000317/20230032023-11-0101 November 2023 Integrated Inspection Report 05000317/2023003 and 05000318/2023003 IR 05000317/20230902023-10-26026 October 2023 Final Significance Determination of a White Finding with Assessment Follow-Up and Notice of Violation; Inspection Report 05000317/2023090 ML23289A1202023-10-16016 October 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation RS-23-097, Constellation Energy Generation, LLC, Advisement of Leadership Changes and Submittal of Updated Standard Practice Procedures Plans2023-10-12012 October 2023 Constellation Energy Generation, LLC, Advisement of Leadership Changes and Submittal of Updated Standard Practice Procedures Plans RS-23-108, Proposed Alternative for Examinations of Examination Categories B-B, B-D, and C-A Steam Generator Pressure Retaining Welds and Full Penetration Welded Nozzles2023-10-11011 October 2023 Proposed Alternative for Examinations of Examination Categories B-B, B-D, and C-A Steam Generator Pressure Retaining Welds and Full Penetration Welded Nozzles RS-23-105, Proposed Alternative for Examinations of Examination Category C-B Steam Generator Nozzle-to-Shell Welds and Nozzle Inside Radius Sections2023-10-10010 October 2023 Proposed Alternative for Examinations of Examination Category C-B Steam Generator Nozzle-to-Shell Welds and Nozzle Inside Radius Sections ML23279A1202023-10-0606 October 2023 Response to NRC Inspection Report and Preliminary White Finding IR 05000317/20230502023-09-29029 September 2023 Special Inspection Report 05000317/2023050 and Preliminary White Finding and Apparent Violation ML23272A1032023-09-29029 September 2023 Condition Prohibited by Technical Specifications Due to Inoperable Nuclear Instrumentation at Very Low Power IR 05000317/20234012023-09-18018 September 2023 Cyber Security Inspection Report 05000317/2023401 and 05000318/2023401 ML23254A0012023-09-0505 September 2023 Registration of Use of Casks to Store Spent Fuel IR 05000317/20230052023-08-31031 August 2023 Updated Inspection Plan for Calvert Cliffs Nuclear Power Plant, Units 1 and 2 (Report 05000317/2023005 and 05000318/2023005) ML23158A1952023-08-30030 August 2023 R. E. Ginna - Issuance of Amendments to Adopt TSTF-273-A, Revision 2, Safety Function Determination Program Clarifications ML23241A8412023-08-29029 August 2023 Response to Request for Additional Information - Proposed Alternative to the Requirements for Repair/Replacement of Saltwater (SW) System Buried Piping ML23240A3872023-08-28028 August 2023 Senior Reactor and Reactor Operator Initial License Examinations ML23151A3472023-08-21021 August 2023 Issuance of Amendments to Adopt TSTF-295-A, Modify Note 2 to Actions of PAM Table to Allow Separate Condition Entry for Each Penetration ML23219A1662023-08-16016 August 2023 Request for Additional Information Regarding Proposed Alternative to the Requirements for Repair/Replacement of Saltwater (SW) System Buried Piping (EPID: L-2023-LLR-0006) - Non-proprietary ML23228A1002023-08-15015 August 2023 Notification of Readiness for NRC 95001 Inspection ML23188A0402023-08-0808 August 2023 Issuance of Amendment Nos. 346 and 324 Adoption of TSTF-577, Revised Frequencies for Steam Generator Tube Inspections, Revision 1 ML23214A1572023-08-0707 August 2023 Correction to the Renewed Facility Operating License Page 3 in Amendment No 345 IR 05000317/20230022023-08-0303 August 2023 Integrated Inspection Report 05000317/2023002 ML23188A0512023-07-13013 July 2023 Correction to the Renewed Facility Operating License Pages in Amendment Nos. 336 and 314 ML23186A0372023-07-13013 July 2023 Correction to the Renewed Facility Operating License Pages in Amendment Nos. 340 and 318 IR 05000317/20233012023-07-12012 July 2023 Initial Operator Licensing Examination Report 05000317/2023301 and 05000318/2023301 IR 05000317/20230122023-07-10010 July 2023 Commercial Grade Dedication Report 05000317/2023012 and 05000318/2023012 ML23180A2362023-06-29029 June 2023 Correction of Errors on Technical Specification Pages RS-23-083, Withdrawal - Proposed Alternatives Related to the Steam Generators2023-06-27027 June 2023 Withdrawal - Proposed Alternatives Related to the Steam Generators ML23156A6752023-06-20020 June 2023 Request for Withholding Information from Public Disclosure for Proposed Alternative to the Requirements for Repair/Replacement of Saltwater System Buried Piping 2024-02-01
[Table view] Category:Request for Additional Information (RAI)
MONTHYEARML24012A0492024-01-11011 January 2024 Request for Additional Information Regarding Final Response to Generic Letter 2004-02 ML23219A1662023-08-16016 August 2023 Request for Additional Information Regarding Proposed Alternative to the Requirements for Repair/Replacement of Saltwater (SW) System Buried Piping (EPID: L-2023-LLR-0006) - Non-proprietary ML23160A0222023-06-0606 June 2023 NRR E-mail Capture - Calvert Cliffs - Long Term Coupon Surveillance Program RAI ML23156A0102023-06-0404 June 2023 NRR E-mail Capture - Calvert Cliffs - RAI License Amendment Request for Emergency Desiel Generator ML22179A2112022-06-28028 June 2022 Notification of Conduct of a Fire Protection Team Inspection ML22129A0132022-05-0606 May 2022 NRR E-mail Capture - Draft RAIs for Requests for Alternatives I4R-17, I4R-23, ISI-05-018, I6R-10 ML22271A0772022-05-0606 May 2022 NRR E-mail Capture - Final RAIs 9.1.2021 Constellation Relief Request ML22091A0852022-04-0101 April 2022 NRR E-mail Capture - Braidwood and Byron - Final RAI Regarding Proposed Alternative for Various Pressurizer Welds (EPID L-2021-LLR-0035 and 0036) ML22091A2392022-04-0101 April 2022 NRR E-mail Capture - Calvert Cliffs - Formal RAI for Proposed Alternative for Examinations of Certain Pressurizer Welds ML22041B5362022-02-10010 February 2022 NRR E-mail Capture - Constellation Energy Generation, LLC - Request for Additional Information Regarding Fleet License Amendment Request to Adopt TSTF-541 ML21287A0322021-10-13013 October 2021 Request for Additional Information Re Proposed Alternative for Pressurizer Circumferential and Longitudinal Shell-to-Head Welds and Nozzle-to-Vessel Welds ML21287A0932021-10-0505 October 2021 Request for Additional Information: Calvert Cliffs 1 & 2 LAR to Revise Spent Fuel Pool Cooling - Shutdown Cooling Systems Licensing Basis (EPID L-2021-LLA-0112) (Email) ML21256A1902021-09-10010 September 2021 NRR E-mail Capture - Exelon Generation Company, LLC - Request for Additional Information Regarding License Transfer Application ML21187A2232021-07-29029 July 2021 Temporary Instruction 2515/194 Inspection Documentation Request ML21180A1562021-06-28028 June 2021 Request for Additional Information Regarding License Amendment Request Concerning Containment Sump ML21144A2132021-05-24024 May 2021 NRR E-mail Capture - Exelon Generation Company, LLC - Request for Additional Information Regarding License Transfer Application ML21130A0382021-05-21021 May 2021 Memo to File - Draft Request for Additional Information Relief Request CISI-03-01 Concerning Containment Unbonded Post-Tensioning System Inservice Inspection Requirements ML21117A0342021-05-0505 May 2021 Request for Additional Information Regarding Proposed Alternative to Use ASME Code Case N-893 ML21062A0652021-03-0101 March 2021 NRR E-mail Capture - Exelon Generation Company, LLC - Request for Additional Information Regarding Proposed Fleet Alternative to Documentation Requirements for Pressure Retaining Bolting ML21053A3142021-02-22022 February 2021 Information Request for a Triennial Baseline Design Bases Assurance Inspection (Team); Inspection Report 05000317/2021010 and 05000318/2021010 ML21049A2572021-02-18018 February 2021 Request for Additional Information Byron/Dresden Proposed Changes to Site Emergency Plans to Support Post-Shutdown and Permanently Defueled Conditions (EPID-2020-LLA-0240 & EPID-2020-LLA-0237) ML21029A3302021-01-29029 January 2021 NRR E-mail Capture - Exelon Generation Company, LLC - Request for Additional Information Regarding Fleet Alternative Request to Use ASME Code Case N-885 ML20275A0032020-09-30030 September 2020 Request for Additional Information Regarding Alternative Request Re Inservice Inspection Impracticality (L-2020-LLR-0089) ML20167A2532020-06-15015 June 2020 Second Request for Additional Information Regarding License Amendment Request Concerning Emergency Diesel Generator Surveillance Requirements for Frequency and Voltage Tolerances ML20157A0782020-06-0505 June 2020 Request for Additional Information Regarding License Amendment Request Concerning Emergency Diesel Generator Surveillance Requirements for Frequency and Voltage Tolerances ML20153A7042020-06-0101 June 2020 NRR E-mail Capture - Preliminary RAI for Fleet Request to Use Alternative OMN-26 ML20135H0132020-05-14014 May 2020 IP 71111.17T (50.59) List of Documents Request ML20083F5892020-03-21021 March 2020 Request for Additional Information Regarding License Amendment Request Concerning Reactor Coolant Pump Flywheel Inspection Program ML19275H1362019-10-0202 October 2019 NRR E-mail Capture - Exelon Generation Company, LLC - Request for Additional Information Regarding Request to Use ASME Code Case N-879 ML19261B2202019-09-18018 September 2019 Request for Additional Information Regarding Final Response to Generic Letter 2004-02 ML19179A0612019-07-19019 July 2019 Three Mile Point 1 - Supplemental Information Needed to Proposed Alternative to Use ASME Code Case N-879 ML19155A1612019-06-11011 June 2019 Changes to Draft Request for Additional Information Request to Adopt 10 CFR 50.69, Risk-Informed Categorization and Treatment of Systems, Structures and Components ML19155A1272019-06-0404 June 2019 Request for Additional Information Regarding Request to Adopt 10 CFR 50.69 Risk Informed Categorization and Treatment of Systems, Structures, and Components ML19070A0192019-03-11011 March 2019 Request for Additional Information Regarding Exemption Request from 10CFR50.46(A)(1) to Support Resolution of GSI-191 ML19025A1202019-01-24024 January 2019 NRR E-mail Capture - Calvert Cliffs, Fitzpatrick, and Nine Mile Point - Request for Additional Information Regarding License Amendment Request to Revise Emergency Response Organization Staffing ML18347A3972018-12-13013 December 2018 Request for Additional Information Regarding Relocation of Emergency Operation Facility ML18138A1372018-05-22022 May 2018 Plants, Units 1 and 2 - Request for Additional Information Regarding Risk Informed Technical Specification Completion Times (CAC Nos. MF7415 and MF7416; EPID L-2016-LLA-0001) ML18128A3842018-05-0808 May 2018 Plants, Units 1 and 2 - Draft Request for Additional Information Regarding Risk-Informed Technical Specification Completion Times (CAC Nos. MF7415 and MF7416; EPID L-2016-LLA-0001) ML18102A2372018-04-12012 April 2018 NRR E-mail Capture - Calvert Cliffs, Ginna, and Nine Mile Point - Request for Additional Information Regarding License Amendment Request to Revise Emergency Action Level Schemes (EPID-L-2017-LLA-0237) ML18067A1482018-03-0808 March 2018 Enclosurequest for Additional Information (Letter to P. R. Simpson Request for Additional Information Regarding Exelon Generating Company, Llc'S Decommissioning Funding Plan Update for Independent Spent Fuel Storage Installation) ML17345A0912018-01-19019 January 2018 Plants, Units 1 and 2 - Request for Additional Information Regarding Alternative Request SI-RR-01, Rev. 0 (CAC Nos. MG0068 and MG0069; EPID L-2017-LLR-0078) ML17346A9092017-12-21021 December 2017 Request for Additional Information Regarding Risk-Informed Technical Specification Completion Times (CAC Nos. MF7415 and MF7416; EPID L-2016-LLA-0001) ML17331B1342017-12-12012 December 2017 2, and R.E. Ginna Nuclear Power Plant - Request for Additional Information - Regarding ML17304A9412017-11-13013 November 2017 Request for Additional Information Regarding Risk-Informed Technical Specification Completion Times (CAC Nos. MF7415 and MF7416; EPID L-2016-LLA-0001) ML17285B1962017-10-27027 October 2017 Request for Additional Information Regarding Generic Letter 2016-01, Monitoring of Neutron-Absorbing Materials in Spent Fuel Pools. ML17075A0152017-03-16016 March 2017 E-mail from R. Guzman to E. Villar - Calvert Cliffs Unit Nos. 1 and 2 - Request for Additional Information License Amendment Request - Control Room Emergency Ventilation System ML17062A4912017-03-0303 March 2017 NRR E-mail Capture - Exelon Generation Company, LLC - Request for Additional Information Regarding Fleet Alternative to RPV Threads in Flange Examination (CAC Nos. MF8712-MF8729) ML16222A1252016-08-0909 August 2016 Request for Additional Information - Relief Request No. RR-ISI-04-11, 2016/08/08 E-mail from R.Guzman to T.Loomis ML15299A2792015-11-0303 November 2015 Request for Additional Information Regarding Relief Request for Dissimilar Metal Butt Welds ML15230A0322015-08-13013 August 2015 Request for Additional Information Regarding the National Association Standard 805 License Amendment Request Fire Protection 2024-01-11
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 September 17, 2014 Mr. George H. Gellrich, Vice President Calvert Cliffs Nuclear Power Plant, LLC Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657-4702
SUBJECT:
CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NOS. 1 AND 2-REQUEST FOR ADDITIONAL INFORMATION REGARDING ATMOSPHERIC DUMP VALVES LICENSE AMENDMENT REQUEST (TAC NOS. MF3388 AND MF3389)
Dear Mr. Gellrich:
By letter dated January 13, 2014, Calvert Cliffs Nuclear Power Plant, LLC submitted a license amendment request to add Technical Specifications for atmospheric dump valves for Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2.
The Nuclear Regulatory Commission (NRC) staff is reviewing the submission and has determined that additional information is needed to complete its review. The specific questions are found in the enclosed request for additional information (RAI). The NRC staff is requesting a response to the RAI within 45 days of the date of this letter.
If you have any questions regarding this issue, please contact me at (301) 415-1016.
Sincerely, Nadiyah S. Morgan, Project Manager Plant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-317 and 50-318
Enclosure:
RAI cc w/encl: Distribution via Listserv
REQUEST FOR ADDITIONAL INFORMATION REGARDING ATMOSPHERIC DUMP VALVES LICENSE AMENDMENT REQUEST CALVERT CLIFFS NUCLEAR POWER PLANT, LLC.
CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NOS. 1 AND 2 DOCKET NOS. 50-317 AND 50-318 By letter dated January 13, 2014 (Agencywide Documents Access and Management System Accession No. ML14015A138), Calvert Cliffs Nuclear Power Plant, LLC, the licensee, submitted a license amendment request (LAR) to add Technical Specifications (TSs) for atmospheric dump valves (ADVs) for Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 (Calvert Cliffs). In order to complete its review, the Nuclear Regulatory Commission (NRC) staff needs the following additional information:
Reactor Systems:
- 1. The LAR refers to the updated final safety analysis report (UFSAR) Section 14.15, "Steam Generator Tube Rupture Event [SGTR]" as the limiting case for radiological releases due to ADV operation. Revision 46 of the UFSAR has the latest analytical evaluations of the Nuclear Steam Supply System response to a postulated SGTR event. Reference 4 of Section 14.15.5 presents the re-analyzed consequences for this event and has the following citation: "CA06595, Westinghouse Calculation CN-TAS-05-13, Revision 000, Calvert Cliffs Units 1 & 2 [SGTR] Event." This calculation package is not currently available to the NRC staff. Please provide the calculation package CA06595, Westinghouse Calculation CN-TAS-05-13, Revision 000.
- 2. On page 5 of the LAR, it is stated that for the SGTR event under UFSAR Section 14.15, the ADV on the affected steam generator (SG) is assumed to open upon turbine and reactor trip and a loss of offsite power. However, UFSAR Section 14.15 does not provide "a loss of offsite power" as an assumption for the presented analysis. The UFSAR states that for the SGTR event analysis, "no credit was taken for the operation of the steam bypass valves to the condenser," it is later stated that other means are available for cooldown, if the ADVs are unavailable.
- a. Because the LAR states, in support of the TS, that the loss of offsite power is an assumption in the UFSAR analysis, provide justification for the loss of offsite power as an assumption in the SGTR event analysis or provide a revised analysis in support of the LAR that includes the loss of offsite power as an initial assumption for the SGTR event.
Enclosure
- b. Provide documentation (analysis and procedures) as to what other means are available for cooldown if the ADVs are unavailable given the event assumptions of a loss of offsite power and no credit being taken for the operation of the steam bypass valves to the condenser.
Balance of Plant:
- 3. The licensee determined that the ADVs meet Title 10 of the Code of Federal Regulations (1 0 CFR) Section 50.36(c)(2)(ii) Criterion 3 and should be included in the plant TSs. The licensee stated that they modeled the proposed newTS upon provision 3.7.4 in NUREG 1432, Revision 4, "Standard Technical Specifications [STS]- Combustion Engineering Plants," March 2012. In the STS bases document that supports TS 3.7.4, it states that four ADV lines are provided. Two ADV lines per SG are necessary in order to have at least one operable following an event rendering one SG unavailable and a single failure renders one of the ADVs inoperable on the other SG.
Specifically, the STS states:
- LCO [Limiting Conditions for Operation] 3.7.4 Condition A (One required ADV line inoperable) a completion time of 7 days.
- LCO 3.7.4 Condition B (Two or more [required] ADV lines inoperable) a completion time of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
The licensee's LAR states:
LCO 3.7.18 Condition A (One required ADV line inoperable) a completion time of 48 days.
- LCO 3. 7.18 Condition 8 (Two ADV lines inoperable) a completion time of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.
The licensee only has two ADV lines per unit and one per SG. The licensee proposes TS 3. 7.18 with a limiting condition for operation requiring two ADVs lines be operable.
The licensee acknowledged that their plant design deviates from the STS design. In accordance with 10 CFR 50.36(b), TSs will be derived from the analyses and evaluation including the safety analysis report.
- a. Please provide a discussion of how the ADVs lines are used in accident mitigation in to order to determine the appropriate TS conditions, actions, and surveillance requirements (SRs).
The discussion should include the following:
The requirements of ADV remote operations The requirements of credited ADV local operation within a certain time restraint.
- The requirements of the ADVs being able to close remotely and manually.
The requirements of the ADV lines meeting single failure assumption, following an event rendering one SG unavailable (i.e., what is licensing basis under single failure considerations).
- The requirements of the ADV block valves being credited in the analysis in the event the ADV fails to close once open.
The technical basis, including a discussion of defense in depth and safety margins for the proposed LCO's 3.7.8, Condition A and B Completion Times of 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> and 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, respectively.
- b. In addition, describe the failure and effects analysis for the ADV line.
- 4. In the bases section of STS 83.7.4- Combustion Engineering Plant, the ADV, also called atmospheric vent valves block valves, are described as part of the ADV line. The STS for the two other types of pressurized water reactors (Westinghouse [83.7.4] and Babcock and Wilcox [83.7.4]) recommends a TS SR for the ADV block valve. In the description of the bases for the proposed TS 83.7 .18, the licensee does include the statement, "Each ADV line consists of one ADV and an associated isolation valve. The ADVs are provided with upstream isolation valves to permit their being tested at power, if desired." However, the licensee did not propose a TS SR for these isolation valves.
If the ADVs cannot be closed due to the failure that causes the ADVs to spontaneously open and remain open, then the licensee can isolate the potential radiological steam release by closing the associated ADV isolation (block) valve.
- a. Justify why there is not a TS surveillance for the ADV block valves.
- b. Verify that the ADVs can be reliably closed in the event the ADV spontaneously opens.
- 5. In UFSAR Section 14.15.1, the licensee stated, "The use of the affected ADV in this analysis is for the purpose of maximizing the radiological releases during the event since the ADVs are not required for cooldown. The ADVs do not perform a safety function; other means are available for cooldown, turbine bypass valves, MSSVs [main steam safety valves], and once-through core cooling, if ADVs are unavailable. If neither ADV were used, releases to the atmosphere would decrease."
Additionally, the licensee states in UFSAR Section 14.15.2, "No credit was taken in the analysis for operation of the steam bypass valves to the condenser. All of the steam releases are assumed to be directed to the atmosphere via the MSSVs or the ADVs."
In the LAR, the licensee stated, in part, "The ADVs are part of the primary success path for cooldown of the Unit following a SGTR. In a SGTR, the fission product barrier [the reactor coolant system (RCS)] is assumed to be failed. Therefore, the ADVs meet 10 CFR 50.36(c)(2)(ii) Criterion 3 and should be included in the TSs. The proposed TS is based on NUREG-1432 and is modified based on plant specific design features."
The licensee's position is unclear in its UFSAR for how a SGTR is to be mitigated. In UFSAR Section 14.15.1, the licensee stated that there are other means available to cooldown the RCS during a SGTR. In the LAR, the licensee explains that the ADVs are
part of the primary success path for cooldown of the Unit following a SGTR. Also, the ADVs are assumed to be used by the operator to cool down the unit to shutdown cooling system entry conditions because the accident is accompanied by a loss of offsite power.
Provide a description (update to UFSAR) of a SGTR event specifically showing which equipment that is now credited for accident mitigation, how that equipment is used, operator actions due to the loss of offsite power, and how a single failure would affect the ability of this equipment to perform its function.
- 6. In the LAR, the licensee provides a discussion of the different types of expected accidents and transients in Table 1, Summary of UFSAR Chapter 14 Event Dispositions.
For the Excess Load Event, UFSAR Section 14.4.3.3 states that the radiological consequence of stuck open atmospheric dump and turbine bypass valves during an Excess Load Event is less adverse than the Loss of Non-Emergency Alternating Current (AC) Power event. Since non-emergency AC power is still available in the Excess Load Event, steam may be directed to the condenser after 10 minutes for controlled plant cooldown. When this happens, the steam (and any activity in it) is no longer being released directly to the atmosphere through the ADVs and MSSVs.
- a. Provide sufficient details on the valve and its failure modes that would cause the valve to spuriously open or fail open.
- b. Identify the method to close the valve or isolate the flow path within 10 minutes, given the valve design and the failure modes.
- c. Identify if this action is time critical and identify if this is a time critical operator action.
- 7. In the LAR, the licensee provides a discussion of the different types of expected accidents and transients in Table 1, Summary of UFSAR Chapter 14 Event Dispositions.
For the Loss of Non-Emergency AC Power Event, UFSAR Section 14.10.2 states that with the atmospheric steam dump and turbine bypass systems inoperable, the SG pressure will rapidly approach the MSSVs' opening pressures. The MSSVs will open as this is the only path for removal of decay heat (i.e., steam). With reactor power decreasing to decay heat levels, the RCS will continue to transfer heat to the SGs, thereby keeping the main steam safeties open.
Also, UFSAR 14.10.2 states that the subcooled auxiliary feedwater decreases the SG temperature and starts to cool down the RCS. At 900 seconds (15 minutes}, the analysis assumes the operator, by remote-manual operation of the ADVs, initiates plant cooldown. Therefore, the ability to remotely operate the ADVs is lost once non-emergency power is lost.
Provide sufficient information on the ADVs to explain how operation is performed within the time constraints identified in the safety analyses.
- 8. In the LAR, the licensee provides a discussion under "Testing History" and stated that the ADVs are very reliable valves and that ten years of Condition Reports were reviewed for any issues related to ADV operation.
The NRC staff reviewed operating experiences for the ADVs at Calvert Cliffs and noted failures that where not described in the LAR.
Provide sufficient information to support your statement for the Calvert Cliffs ADVs 1/2-CV-3938 and 1/2-CV-3939. The ADVs that fail to open, fail to close, seat leakage, etc. should be described in the LAR.
- 9. In the LAR, the licensee stated that, "if local manual operation is required, the ADVs can be locally opened or closed using a hand wheel attached to the ADV. The hand wheel is external to the ADV enclosure in the Auxiliary Building. The area is accessible following a turbine and reactor trip or an accident. Intermediate positioning of the ADV can also be performed using the hand wheel. The ADVs controls receive electrical power from emergency diesel generator-backed, engineered safety feature, 125 VDC unit control panels. When electrical power is unavailable, the quick-opening feature is disabled.
The ADVs may still be automatically or manually controlled from the Control Room.
Loss of control voltage also actuates an alarm in the Control Room. Local manual operation of the ADVs does not require electrical power or air to function as designed."
The ADV automatic controls and manual controls were not described in detail for the NRC staff to understand the valve controls and interactions. Provide the emergency procedures and sufficient information relate to manual ADV controls. Specifically, if the operator in the field takes over manual control of the ADV, are control signals from the reactor regulation system disabled? If so, how is the instrument logic locked out from controlling the ADV?
- 10. In the LAR, the licensee stated that, "the ADVs and turbine bypass valves reduce, but do not eliminate, the probability of the main steam safety valves (MSSVs) opening following turbine and reactor trips from full power. The steam dump system is safety-related. Two normally shut ADVs are connected to the main steam headers between the containment penetrations and the MSSVs. When opened, the ADVs exhaust part of the secondary steam flow to the atmosphere through separate vent enclosures which extend from the 45-foot level up through the roof of the Auxiliary Building."
Details of the ADV exhaust path pipe routing through the Auxiliary Building roof is not specified. Provide sufficient information related to the ADV piping extension up through the roof of the Auxiliary Building. Specifically, are the ADV exhaust path and pipe route designed against damage from hurricane or tornado generated missiles? Clarify the safety classification of the piping extension and whether it has been reviewed against vulnerability of hurricane or tornado generated missiles.
September 17, 2014 Mr. George H. Gellrich, Vice President Calvert Cliffs Nuclear Power Plant, LLC Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657-4702
SUBJECT:
CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NOS. 1 AND 2-REQUEST FOR ADDITIONAL INFORMATION REGARDING ATMOSPHERIC DUMP VALVES LICENSE AMENDMENT REQUEST (TAC NOS. MF3388 AND MF3389)
Dear Mr. Gellrich:
By letter dated January 13, 2014, Calvert Cliffs Nuclear Power Plant, LLC submitted a license amendment request to add Technical Specifications for atmospheric dump valves for Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2.
The Nuclear Regulatory Commission (NRC) staff is reviewing the submission and has determined that additional information is needed to complete its review. The specific questions are found in the enclosed request for additional information (RAI). The NRC staff is requesting a response to the RAI within 30 days of the date of this letter.
If you have any questions regarding this issue, please contact me at (301) 415-1016.
Sincerely, IRA/
Nadiyah S. Morgan, Project Manager Plant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-317 and 50-318
Enclosure:
RAI cc w/encl: Distribution via Listserv DISTRIBUTION:
PUBLIC RidsNrrDoriLpli-1 RidsNrrPMCalvertCiiffs LPLI-1 R/F RidsNrrLAKGoldstein RidsAcrsAcnw_MaiiCTR RidsNrrDoriDpr RidsRgn1 MaiiCenter RidsNrrDssSbpb RidsOGCMaiiCenter RidsNrrDssSrxb D. Palmrose M. Hamm L. Wheeler ADAMS ACCESSION NO: ML14237A069 *See dated memo OFFICE LPLI-1/PM LPLI-1/LA DSS/SRXB/BC DSS/SBPB/BC LPLI-1/BC NAME NMorgan KGoldstein CJackson GCasto BBeasley DATE 9/15/2014 08/27/2014 7/8/2014 7/25/2014 9/17/14 OFFICIAL RECORD COPY