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MONTHYEARML0429904522004-10-27027 October 2004 RAI, License Amendment Request to Use Alternate Decay Heat Removal in Mode 6 Refueling Project stage: RAI ML0432100882004-11-22022 November 2004 FRN: General Notice - Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 - Notice of Consideration of Issuance of Amendment to Renewed Facility Operating License and Opportunity for a Hearing Project stage: Other ML0500500112005-01-0404 January 2005 Request for Additional Information (RAI) License Amendment Request to Use Alternate Decay Heat Removal in Mode 6 Refueling Project stage: RAI ML0506900362005-03-0303 March 2005 Response to RAI Concerning License Amendment Request: Use of Alternative Decay Heat Removal in Mode 6 Refueling Project stage: Response to RAI ML0510902052005-04-25025 April 2005 Withdrawal of an Amendment Request Project stage: Withdrawal 2005-01-04
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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
[Table view] |
Text
January 4, 2005 Mr. George Vanderheyden, Vice President Calvert Cliffs Nuclear Power Plant, Inc.
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 (RAI) RE: LICENSE AMENDMENT REQUEST TO USE ALTERNATE DECAY HEAT REMOVAL IN MODE 6 REFUELING (TAC NOS. MC3595 AND MC3596)
Dear Mr. Vanderheyden:
By letter dated June 7, 2004, you requested an amendment to incorporate the use of an alternate cooling method to function as a path for decay heat removal when in Mode 6 with the refueling pool fully flooded. In reviewing your submittal, the Nuclear Regulatory Commission (NRC) staff has determined that additional information contained in the enclosure to this letter is needed to complete its review. An advanced copy of these questions was provided and discussed with your staff on November 10, 2004. The NRC staff had also requested information for the subject license amendment request in a letter dated October 27, 2004. As discussed with your staff, we request you respond to both RAIs within 60 days of the date of this letter to support our review schedule.
If you have any questions, please contact me at 301-415-1030.
Sincerely,
/RA/
Richard V. Guzman, Project Manager, Section 1 Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-317 and 50-318
Enclosure:
As stated cc w/encl: See next page
ML050050011 OFFICE PDI-1/PM PDI-1/LA SPLB/SC SRXB/SC PDI-1/SC NAME RGuzman SLittle SJones JUhle RLaufer DATE 12/20/04 12/20/04 1/4/05 1/4/05 1/4/05 REQUEST FOR ADDITIONAL INFORMATION (RAI) CONCERNING AMENDMENT REQUEST TO USE ALTERNATE COOLING METHOD IN MODE 6 REFUELING CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NOS. 1 AND 2 (CCNPP 1 AND 2)
DOCKET NOS. 50-317 AND 50-318 By letter dated June 7, 2004, Calvert Cliffs Nuclear Power Plant, Inc. (CCNPPI), requested a license amendment to revise Technical Specification (TS) 3.9.4, Shutdown Cooling (SDC) and Coolant Circulation-High Water Level, to permit the operation of a spent fuel pool (SFP) cooling loop providing cooling to the refueling pool in place of one SDC loop operable and in operation. This TS applies in Mode 6, Refueling, with 23 feet or more water above the top of irradiated fuel seated in the reactor vessel. Existing TS 3.9.3, Shutdown Cooling (SDC) and Coolant Circulation-Low Water Level, permits one SFP cooling loop capable of providing adequate cooling to the refueling pool and reactor vessel to replace one of two SDC loops required to be operable in Mode 6 with less than 23 feet of water above the top of irradiated fuel seated in the reactor vessel.
The provision allowing the substitution of one SFP cooling loop for one of two operable SDC loops in Mode 6 at low water level was issued by Amendment Nos. 55 and 38 for Unit Nos. 1 and 2, respectively, dated June 16, 1981. The preceding amendment request was based on a Nuclear Regulatory Commission (NRC) Generic Letter (GL) addressed to all operating pressurized-water reactors (later numbered GL 80-053) dated June 11, 1980, that requested each licensee to propose an amendment to their facilitys TSs to improve the reliability of reactor decay heat removal (DHR) capability. The licensee for CCNPP 1 and 2 proposed the model TSs included with GL 80-053, with modifications including the provision to substitute a spent fuel cooling loop for one of two operable SDC loops. The NRC approved the amendment on the basis that the revised TS was more conservative than the existing specification in that it required an additional DHR subsystem be maintained operable in the event the operating subsystem became inoperable. The amendment did not include an evaluation of the reliability or capability of the SFP cooling loop in providing DHR for irradiated fuel located in the reactor vessel.
By letter dated May 12, 2003, Westinghouse Electric Company submitted Topical Report WCAP-15782, Rev. 0 (non-proprietary), Use of Alternate Decay Heat Removal in Mode 6 Refueling, for NRC review. The report included a description of the alternate DHR system alignment, a description of system modeling, a description of validation of model predictions to in-plant measurements, a qualitative assessment of risk during operation of alternate DHR, a description of a method to determine alternate DHR entry conditions, and a proposed change to TSs. This topical report relied, in part, on plant-specific information from Calvert Cliffs Nuclear Power Plant, including details used in the qualitative assessment of risk and the validation of system modeling. The license amendment request dated June 7, 2004, references this topical report.
In order to complete our review, the NRC staff requests that CCNPPI provide the following information:
Enclosure
- 1. Pressure Boundary Qualification: Regulatory Guide (RG) 1.29 and Standard Review Plan (SRP) Section 5.4.7 specify that components whose failure could cause an unacceptable reduction in the capability of the residual heat removal system should be safety related (i.e., designed as Seismic Category I and subject to the quality assurance criteria of Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix B). With the plant in the configuration permitted by the proposed revision to TS 3.9.4, a significant loss of cooling water inventory would cause an unacceptable reduction in the capability of the residual heat removal system in that both the alternate DHR path and the large capacity heat sink provided by the coolant inventory would be lost. SRP Section 3.2.2 and position C.1.b of RG 1.26 specify that portions of the shutdown cooling system essential for performance of the residual heat removal safety function be designed to Quality Group B. Describe the extent that the following pressure boundaries necessary to prevent a significant loss of coolant inventory from the refueling cavity satisfy the criteria of position C.1 of RG 1.29 and position C.1.b of RG 1.26: the refueling cavity (e.g., the refueling cavity-to-reactor vessel seal.
interfacing piping, and the cavity liner), the fuel transfer canal (assuming the fuel transfer tube is open), any regularly used temporary reactor coolant system boundaries (e.g., steam generator nozzle dams), and the portions of the SFP cooling loop connected to the refueling cavity.
- 2. Loss of Inventory Events and Mitigation Capability: Section 3.1.3 of WCAP-15872 includes the statement that, for events such as a reactor cavity seal failure or a steam generator nozzle dam failure that cause a significant loss of cooling water inventory, the traditional SDC loop should continue to function while the alternate DHR capability would be unavailable. Industry operating experience includes examples where the pressure boundary formed by the reactor cavity seal and steam generator nozzle dams have failed such that a rapid and gross loss of cooling water did result or could have resulted. NRC SRP Section 5.4.7 and General Design Criterion (GDC) 34 specify that the residual heat removal function be available assuming a single failure. For pressure boundary components such as refueling cavity seals and steam generator nozzle dams that do not meet the quality criteria specified in position C.1 of RG 1.29 and position C.1.b of RG 1.26, explain how the loss of the available alternate DHR path following the failure of these components would be prevented or mitigated to retain the residual heat removal function. If necessary, describe the basis for excluding the systems, structures, and components that provide this mitigation capability from the TSs considering the requirements of 10 CFR 50.36.
- 3. Containment closure: The existing action statements associated with TS 3.9.4 require that containment closure be achieved within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> of a loss of forced cooling for the DHR function. The basis for the 4-hour completion time is the low probability of boiling beginning within the 4-hour period. In the alternate DHR configuration, a steam generator nozzle dam failure could result in reactor vessel boiling in a short time because no SDC loop would be readily available to cool the small inventory of water that would remain in the reactor vessel below the elevation of the steam generator manway. Time to boil would be longer for a refueling cavity seal failure because the remaining cooling water inventory is slightly larger. For pressure boundary components such as refueling cavity seals
and steam generator nozzle dams that do not meet the quality criteria specified in position C.1 of RG 1.29 and position C.1.b of RG 1.26, explain how the basis of the containment closure action statement would be satisfied following the failure of these components with only the alternate DHR path available.
- 4. Boron Dilution: The piping and instrumentation diagram of the SFP cooling loop indicates that demineralized water can be supplied directly to the refueling water cavity through the SFP cooling system. Evaluation of the temperature distribution within the refueling cavity during operation of the alternate DHR path in WCAP-15872 indicates that cool water entering the refueling cavity from the SFP cooling loop remains stratified, spills over the reactor vessel flange, and flows downward directly into the reactor vessel. Neither the topical report nor the license amendment request explicitly addressed boron dilution from this flow path. Describe how boron dilution from this path affects the boron concentration within the reactor vessel and how continued dilution would be assured of being detected and mitigated prior to dilution below the minimum boron concentration required to maintain an adequate margin to criticality.
- 5. Spent Fuel Pool Cooling Reliability: The SFP pool cooling system is a shared system that cools the two normally connected SFPs at Calvert Cliffs. The system includes two SFP cooling loops operating in parallel, each loop consisting of one half-capacity pump and one half capacity heat exchanger. The alternate DHR path uses one loop to cool the refueling cavity and connected reactor vessel instead of the SFP. However, the Calvert Cliffs Updated Final Safety Analysis Report (UFSAR), Revision 26, states that, in the event one SFP cooling loop is lost, the remaining loop can remove a heat load associated with a recent partial core discharge while maintaining the SFP temperature at 155 EF. The Calvert Cliffs UFSAR also states that a complete loss of cooling is not part of the design basis for the SFP structural components and the SFP cooling system.
Explain how these design bases and the requirements of the proposed TS 3.9.4 would be satisfied when one spent fuel cooling loop is operating as an alternate reactor vessel DHR path and no shutdown cooling loop is operable.
- 6. Reliability of the Alternate DHR Path: Describe the reliability of an SFP cooling loop when used as an alternate to an SDC loop. Specifically address vulnerability to blockage of each spent fuel cooling loop suction by rigid (e.g.,
steel deck material on the refueling bridge) or flexible (e.g., clothing, rubber gloves, and tape) materials that may be located in, over, or around the refueling pool and the potential for significant pump damage as a result of suction blockage. Also, compare the redundancy of flowpaths, pumps, and electrical power supplies of the SFP loop with an SDC loop.
- 7. Instrumentation: GDC 63 specifies that appropriate systems be provided in fuel storage and handling areas to detect conditions that may result in a loss of residual heat removal capability. Describe how the isolation of the SDC loops from the reactor coolant system affect the ability to effectively monitor parameters associated with residual heat removal, such as temperature and pressure (as a surrogate for water level). Describe the frequency and location of monitoring of the refueling cavity and SFP water level when alternate DHR is in operation, and any annunciated alarms associated with these parameters.
Address how this monitoring assures a low probability of a significant inadvertent draindown of the refueling cavity.
- 9. Fuel Handling: The license amendment request indicates that the average temperature of the refueling cavity would be higher with alternate DHR in service than with an SDC loop in service and that the water directly above the reactor vessel would be significantly above the average temperature. Describe how the effect of the resulting higher air temperatures and humidity levels on human performance would be managed to prevent a significant increase in human errors during fuel handling.
- 10. TS Bases: Provide revised bases for the proposed amendment to TS 3.9.4, as specified by 10 CFR 50.90, 10 CFR 50.34(b)(6)(vi), and 10 CFR 50.36(a).
- 11. Final Safety Analysis Report: The NRC staff did not identify any discussion of the alternate DHR path in Final Safety Analysis Report (FSAR) Section 9.2, Shutdown Cooling System, or Section 9.4, Spent Fuel Pool Cooling System.
Identify any FSAR sections that were updated to describe the alternate DHR path following issuance of the associated license amendment on June 16, 1981.
Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 cc:
President Co-Director Calvert County Board of Maryland Safe Energy Coalition Commissioners P.O. Box 33111 175 Main Street Baltimore, MD 21218 Prince Frederick, MD 20678 Mr. Loren F. Donatell James M. Petro, Esquire NRC Technical Training Center Counsel 5700 Brainerd Road Constellation Energy Chattanooga, TN 37411-4017 750 East Pratt Street, 17th floor Baltimore, MD 21202 Jay E. Silberg, Esquire Shaw, Pittman, Potts, and Trowbridge 2300 N Street, NW Washington, DC 20037 Lou Larragoite Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657-4702 Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 287 St. Leonard, MD 20685 Mr. R. I. McLean, Administrator Radioecology Environ Impact Prog Department of Natural Resources Nuclear Evaluations 580 Taylor Avenue Tawes State Office Building Annapolis, MD 21401 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Kristen A. Burger, Esquire Maryland People's Counsel 6 St. Paul Centre Suite 2102 Baltimore, MD 21202-1631 Patricia T. Birnie, Esquire