Letter Sequence Request |
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EPID:L-2021-LLR-0039, American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternative RP-10 (Open) |
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MONTHYEARCNL-21-060, Supplement to Sequoyah Nuclear Plant (Sqn), Unit 1, American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternative RP-102021-05-28028 May 2021 Supplement to Sequoyah Nuclear Plant (Sqn), Unit 1, American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternative RP-10 Project stage: Request CNL-21-059, American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternative RP-102021-05-28028 May 2021 American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternative RP-10 Project stage: Request ML21266A3892021-05-28028 May 2021, 2 June 2021, 1 October 2021 Authorization of Alternative Request RP-10 for the 1B-B Motor Driven Auxiliary Feedwater Pump Project stage: Request ML21152A1252021-06-0202 June 2021 Summary of Verbal Authorization of Alternative Request RP-10 for the 1B-B Motor Driven Auxiliary Feedwater Pump Project stage: Other ML21266A3832021-10-0101 October 2021 Authorization of Alternative Request RP-10 for the 1B-B Motor Driven Auxiliary Feedwater Pump Project stage: Other 2021-05-28
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Category:Letter type:CNL
MONTHYEARCNL-24-040, Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2024-05-0808 May 2024 Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure Revisions CNL-24-037, Clinch River, Sequoyah, Units 1 and 2, Watts Bar, Unit 1 and 2, Nuclear Quality Assurance Plan, TVA-NQA-PLN89-A, Revision 422024-04-22022 April 2024 Clinch River, Sequoyah, Units 1 and 2, Watts Bar, Unit 1 and 2, Nuclear Quality Assurance Plan, TVA-NQA-PLN89-A, Revision 42 CNL-24-024, Hydrologic Engineering Center River Analysis System Project Milestone Status Update2024-04-17017 April 2024 Hydrologic Engineering Center River Analysis System Project Milestone Status Update CNL-24-033, Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2024-04-17017 April 2024 Central Emergency Control Center Emergency Plan Implementing Procedure Revisions CNL-23-006, Application to Modify Technical Specifications 3.8.1, AC Sources – Operating, and 3.8.2, AC Sources – Shutdown, for Sequoyah Nuclear Plant (SQN-TSC-22-03)2024-04-15015 April 2024 Application to Modify Technical Specifications 3.8.1, AC Sources – Operating, and 3.8.2, AC Sources – Shutdown, for Sequoyah Nuclear Plant (SQN-TSC-22-03) CNL-24-020, Clinch River, Sequoyah, Units 1 and 2, Watts Bar, Units 1 and 2, Request for Approval of Quality Assurance Program Description and Application to Revise the Technical Specifications Associated with QAPD Requirements2024-04-0101 April 2024 Clinch River, Sequoyah, Units 1 and 2, Watts Bar, Units 1 and 2, Request for Approval of Quality Assurance Program Description and Application to Revise the Technical Specifications Associated with QAPD Requirements CNL-24-007, Annual Insurance Status Report2024-03-27027 March 2024 Annual Insurance Status Report CNL-24-008, Guarantee of Payment of Deferred Premiums - 2023 Annual Report2024-03-27027 March 2024 Guarantee of Payment of Deferred Premiums - 2023 Annual Report CNL-24-027, Response to Request for Additional Information Regarding Sequoyah Nuclear Plant, Units 1 and 2, Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation2024-03-14014 March 2024 Response to Request for Additional Information Regarding Sequoyah Nuclear Plant, Units 1 and 2, Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation CNL-24-029, Response to Request for Additional Information Regarding Tennessee Valley Authority - Request for Exemption from Specific Requirements of 10 CFR Part 372024-03-14014 March 2024 Response to Request for Additional Information Regarding Tennessee Valley Authority - Request for Exemption from Specific Requirements of 10 CFR Part 37 CNL-24-017, Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure and Emergency Preparedness Department Procedure Revisions2024-01-17017 January 2024 Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure and Emergency Preparedness Department Procedure Revisions CNL-23-068, Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation2023-12-21021 December 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation CNL-23-036, Application to Revise Function 5 of Technical Specification Table 3.3.2-1, Engineered Safety Feature Actuation System Instrumentation, for the Sequoyah Nuclear Plant and Watts Bar Nuclear Plant (SQN-TS-23-02 and WBN-TS-23-08)2023-12-18018 December 2023 Application to Revise Function 5 of Technical Specification Table 3.3.2-1, Engineered Safety Feature Actuation System Instrumentation, for the Sequoyah Nuclear Plant and Watts Bar Nuclear Plant (SQN-TS-23-02 and WBN-TS-23-08) CNL-23-067, Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2023-11-27027 November 2023 Central Emergency Control Center Emergency Plan Implementing Procedure Revisions CNL-23-061, Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure Revision2023-09-20020 September 2023 Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure Revision CNL-23-059, Supplement to Sequoyah Nuclear Plant, Units 1 and 2, and Watts Bar Nuclear Plant, Units 1 and 2, Application to Revise Technical Specifications to Adopt TSTF-567-A, Revision 1, Add Containment Sump TS to Address GSI-191 Issues (SQN-TS-23-2023-09-20020 September 2023 Supplement to Sequoyah Nuclear Plant, Units 1 and 2, and Watts Bar Nuclear Plant, Units 1 and 2, Application to Revise Technical Specifications to Adopt TSTF-567-A, Revision 1, Add Containment Sump TS to Address GSI-191 Issues (SQN-TS-23-03 CNL-23-057, Central Emergency Control Center Emergency Plan Implementing Procedure Revisions. Includes CECC-EPIP-1, Revision 76 and CECC-EPIP-9, Revision 642023-09-0505 September 2023 Central Emergency Control Center Emergency Plan Implementing Procedure Revisions. Includes CECC-EPIP-1, Revision 76 and CECC-EPIP-9, Revision 64 CNL-23-028, Application to Revise Technical Specifications to Adopt TSTF-567-A, Revision 1, Add Containment Sump TS to Address GSI-191 Issues (SQN-TS-23-03 and WBN-TS-23-06)2023-08-0202 August 2023 Application to Revise Technical Specifications to Adopt TSTF-567-A, Revision 1, Add Containment Sump TS to Address GSI-191 Issues (SQN-TS-23-03 and WBN-TS-23-06) CNL-23-055, Tennessee Valley Authority - Emergency Preparedness Department Procedure Revision. Includes EPDP-3, Revision 3, Emergency Plan Exercises and Preparedness Drills2023-07-25025 July 2023 Tennessee Valley Authority - Emergency Preparedness Department Procedure Revision. Includes EPDP-3, Revision 3, Emergency Plan Exercises and Preparedness Drills CNL-23-053, Tennessee Valley Authority - Radiological Emergency Plan Revisions2023-07-18018 July 2023 Tennessee Valley Authority - Radiological Emergency Plan Revisions CNL-23-049, Tennessee Valley Authority - Radiological Emergency Plan and Central Emergency Control Center Emergency Plan .2023-06-26026 June 2023 Tennessee Valley Authority - Radiological Emergency Plan and Central Emergency Control Center Emergency Plan . CNL-23-042, Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2023-05-16016 May 2023 Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions CNL-23-032, Clinch River, Sequoyah, Units 1 and 2, Watts Bar, Unit 1 and 2, Nuclear Quality Assurance Plan, TVA-NQA-PLN89-A, Revision 412023-04-27027 April 2023 Clinch River, Sequoyah, Units 1 and 2, Watts Bar, Unit 1 and 2, Nuclear Quality Assurance Plan, TVA-NQA-PLN89-A, Revision 41 CNL-23-030, Tennessee Valley Authority - Hydrologic Engineering Center River Analysis System Project Milestone Status Update2023-04-27027 April 2023 Tennessee Valley Authority - Hydrologic Engineering Center River Analysis System Project Milestone Status Update CNL-23-033, Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revision2023-04-24024 April 2023 Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revision CNL-23-029, Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2023-04-11011 April 2023 Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions CNL-23-012, Revision to the Application to Revise Updated Final Safety Analysis Report Regarding Changes to Hydrologic Analysis, (TS-19-02)2023-04-11011 April 2023 Revision to the Application to Revise Updated Final Safety Analysis Report Regarding Changes to Hydrologic Analysis, (TS-19-02) CNL-23-023, Annual Insurance Status Report2023-03-30030 March 2023 Annual Insurance Status Report CNL-23-024, TVA Guarantee of Payment of Deferred Premiums - 2022 Annual Report2023-03-29029 March 2023 TVA Guarantee of Payment of Deferred Premiums - 2022 Annual Report CNL-23-022, Decommissioning Funding Status Report2023-03-29029 March 2023 Decommissioning Funding Status Report CNL-23-021, Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2023-03-0808 March 2023 Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions CNL-22-037, Application to Revise Technical Specifications to Adopt TSTF-541-A, Add Exceptions to Surveillance Requirements for Valves and Dampers Locked in the Actuated Position (BFN TS-533)2023-01-31031 January 2023 Application to Revise Technical Specifications to Adopt TSTF-541-A, Add Exceptions to Surveillance Requirements for Valves and Dampers Locked in the Actuated Position (BFN TS-533) CNL-23-003, Browns Nuclear Plant, Units 1, 2 & 3; Sequoyah Nuclear Plant, Units 1 & 2; and Watts Bar Nuclear Plant, Units 1 & 2 - Organizational Topic Report TVA-NPOD89-A2023-01-30030 January 2023 Browns Nuclear Plant, Units 1, 2 & 3; Sequoyah Nuclear Plant, Units 1 & 2; and Watts Bar Nuclear Plant, Units 1 & 2 - Organizational Topic Report TVA-NPOD89-A CNL-23-011, Steam Generator Tube Inspection Report to Reflect TSTF-577 Reporting Requirements2023-01-18018 January 2023 Steam Generator Tube Inspection Report to Reflect TSTF-577 Reporting Requirements CNL-23-009, Response to Request for Additional Information Request to Revise Technical Specification 3.4.122023-01-0404 January 2023 Response to Request for Additional Information Request to Revise Technical Specification 3.4.12 CNL-23-008, Tennessee Valley Authority Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2022-12-22022 December 2022 Tennessee Valley Authority Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions CNL-22-106, Tennessee Valley Authority - Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revision. Includes CECC EPIP-14, Revision 38, Nuclear Emergency Public Information Organization and Operat2022-11-28028 November 2022 Tennessee Valley Authority - Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revision. Includes CECC EPIP-14, Revision 38, Nuclear Emergency Public Information Organization and Operatio CNL-22-099, Tennessee Valley Authority - Hydrologic Engineering Center River Analysis System Project Milestone Status Update2022-10-31031 October 2022 Tennessee Valley Authority - Hydrologic Engineering Center River Analysis System Project Milestone Status Update CNL-22-104, Correction to Response to Request for Additional Information Regarding Sequoyah Nuclear Plant, Units 1 and 2, American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternative RV-022022-10-31031 October 2022 Correction to Response to Request for Additional Information Regarding Sequoyah Nuclear Plant, Units 1 and 2, American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternative RV-02 CNL-22-098, Tennessee Valley Authority - Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions. Includes CECC EPIP-7, Rev. 45 & CECC EPIP-8, Rev. 552022-10-17017 October 2022 Tennessee Valley Authority - Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions. Includes CECC EPIP-7, Rev. 45 & CECC EPIP-8, Rev. 55 CNL-22-084, Response to Request for Additional Information Regarding License Amendment Request to License Amendment Request to Modify Approved 10 CFR 50.69 Categorization Process (SQN-TS-21-07)2022-09-16016 September 2022 Response to Request for Additional Information Regarding License Amendment Request to License Amendment Request to Modify Approved 10 CFR 50.69 Categorization Process (SQN-TS-21-07) CNL-22-085, Response to Request for Additional Information Regarding Sequoyah Nuclear Plant (Sqn), Units 1 and 2 and Watts Bar Nuclear Plant (Wbn), Units 1 and 2, American Society of Mechanical Engineers Operation and Maintenance Code, Request for Al2022-09-0202 September 2022 Response to Request for Additional Information Regarding Sequoyah Nuclear Plant (Sqn), Units 1 and 2 and Watts Bar Nuclear Plant (Wbn), Units 1 and 2, American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alte CNL-22-053, Response to Request for Additional Information Regarding Application to Revise Sequoyah Nuclear Plant Units 1 and 2 Updated Final Safety Analysis Report Regarding Changes to Hydrologic Analysis - Second Partial Response to Additional Requ2022-08-22022 August 2022 Response to Request for Additional Information Regarding Application to Revise Sequoyah Nuclear Plant Units 1 and 2 Updated Final Safety Analysis Report Regarding Changes to Hydrologic Analysis - Second Partial Response to Additional Reques CNL-22-077, Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2022-08-11011 August 2022 Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions CNL-22-030, Application to Revise Technical Specification 3.4.12, Low Temperature Overpressure Protection System for Sequoyah Nuclear Plant (SQN-TSC-22-01) and TS 3.4.12 Cold Overpressure Mitigation System for Watts Bar Nuclear Plant (WBN-TS-22-03)2022-07-27027 July 2022 Application to Revise Technical Specification 3.4.12, Low Temperature Overpressure Protection System for Sequoyah Nuclear Plant (SQN-TSC-22-01) and TS 3.4.12 Cold Overpressure Mitigation System for Watts Bar Nuclear Plant (WBN-TS-22-03) CNL-22-080, Request for Enforcement Discretion from the Requirements of Technical Specification 3.5.2, ECCS - Operating2022-07-22022 July 2022 Request for Enforcement Discretion from the Requirements of Technical Specification 3.5.2, ECCS - Operating CNL-22-081, Supplement to Sequoyah Nuclear Plant, Unit 1, American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternative RP-122022-07-21021 July 2022 Supplement to Sequoyah Nuclear Plant, Unit 1, American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternative RP-12 CNL-22-079, American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternative RP-122022-07-20020 July 2022 American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternative RP-12 CNL-22-039, Application to Revise Technical Specifications to Adopt TSTF-554-A, Revision 1, Revise Reactor Coolant Leakage Requirements (BFN TS-537) (SQN-21-05) (WBN-TS-21-04)2022-07-13013 July 2022 Application to Revise Technical Specifications to Adopt TSTF-554-A, Revision 1, Revise Reactor Coolant Leakage Requirements (BFN TS-537) (SQN-21-05) (WBN-TS-21-04) CNL-22-071, Supplement to Application to Revise Technical Specifications to Adopt TSTF-577, Revised Frequencies for Steam Generator Tube Inspections (SQN-TS-21-03 and WBN-TS-21-08)2022-07-13013 July 2022 Supplement to Application to Revise Technical Specifications to Adopt TSTF-577, Revised Frequencies for Steam Generator Tube Inspections (SQN-TS-21-03 and WBN-TS-21-08) 2024-05-08
[Table view] Category:Request for Code Relief or Alternative
MONTHYEARCNL-22-079, American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternative RP-122022-07-20020 July 2022 American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternative RP-12 CNL-22-049, American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternatives RP-11 (SQN) and IST-RR-9 (WBN)2022-04-26026 April 2022 American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternatives RP-11 (SQN) and IST-RR-9 (WBN) CNL-22-009, Request for Relief from American Society of Mechanical Engineers Boiler & Pressure Vessel Code, Section XI, In.2022-04-25025 April 2022 Request for Relief from American Society of Mechanical Engineers Boiler & Pressure Vessel Code, Section XI, In. CNL-22-024, American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternative RV-022022-03-15015 March 2022 American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternative RV-02 CNL-21-059, American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternative RP-102021-05-28028 May 2021 American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternative RP-10 CNL-21-037, Request for Alternative, 21-ISI-1 Alternative Repair and Examination for Mid Canopy Seal Weld Replacement2021-03-26026 March 2021 Request for Alternative, 21-ISI-1 Alternative Repair and Examination for Mid Canopy Seal Weld Replacement 2022-07-20
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1101 Market Street, Chattanooga, Tennessee 37402 CNL-21-059 May 28, 2021 10 CFR 50.55a ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Sequoyah Nuclear Plant, Unit 1 Renewed Facility Operating License No. DPR-77 NRC Docket No. 50-327
Subject:
Sequoyah Nuclear Plant (SQN), Unit 1, American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternative RP-10 In accordance with Title 10 of the Code of Federal Regulations (10 CFR) 50.55a, "Codes and Standards," paragraphs (z)(2), Tennessee Valley Authority (TVA) requests an alternative to the inservice testing requirements of the American Society of Mechanical Engineers (ASME) Operation and Maintenance (OM) Code, Section ISTB-3310, Effect of Pump Replacement, Repair, and Maintenance on Reference Values. This alternative request applies to testing of the Motor Driven Auxiliary Feedwater (MDAFW) Pump 1B-B for the Sequoyah Nuclear Plant (SQN), Unit 1 (alternative request RP-10).
Due to a fire in inboard pump bearing on MDAFW Pump 1B-B, while operating in support of a forced outage with SQN Unit 1 in Mode 3, replacement of the pump is necessary. The ASME OM Code ISTB-3310 requires a preservice test to be performed following pump replacement to establish new reference values and acceptance criteria before declaring the pump operable. As discussed in the enclosure to this letter, compliance with ISTB-3310 would cause a hardship or unusual difficulty without a compensating increase in the level of quality or safety. Therefore, TVA is submitting this one-time alternative request in accordance with 10 CFR 50.55a(z)(2). The enclosure to this letter describes the proposed alternative and the basis for use.
TVA requests verbal approval of this alternative request within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> from the time and date of this submittal in order to support the timeline for restoring the MDAFW Pump 1B-B to operable status prior to completion of the 72-hour completion time for SQN Unit 1 TS 3.7.5 Condition B.
U.S. Nuclear Regulatory Commission CNL-21-059 Page 2 May 28, 2021 There are no new regulatory commitments associated with this submittal. Please address any questions regarding this request to Kimberly D. Hulvey, Senior Manager, Fleet Licensing, at (423) 751-3275.
Respectfully, James T. Polickoski Director, Nuclear Regulatory Affairs
Enclosure:
American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternative RP-10 cc (w/Enclosure):
NRC Regional Administrator - Region II NRC Senior Resident Inspector - Sequoyah Nuclear Plant NRC Project Manager - Sequoyah Nuclear Plant
Enclosure American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alternative RP-10 Motor Driven Auxiliary Feedwater Pump 1B-B Alternative Test I. American Society of Mechanical Engineers (ASME) Operation and Maintenance (OM) Code Components Affected Site/Unit Pump ID Pump Description Pump Code OM Type Class Group Sequoyah SQN-1-PMP-003-0128 Motor Driven Centrifugal-Nuclear Auxiliary Horizontal, Plant Feedwater 3 A Fixed (SQN) (MDAFW) Pump Speed Unit 1 1B-B II. ASME Code Edition and Addenda SQN Unit 1 Fourth ten-year interval - September 1, 2016 to June 30, 2026 ASME OM Code 2004 Edition through 2006 Addenda III. Applicable Code Requirement ISTB-3310, Effect of Pump Replacement, Repair, and Maintenance on Reference Values, states:
When a reference value or set of values may have been affected by repair, replacement, or routine servicing of a pump, a new reference value or set of values shall be determined in accordance with ISTB-3300, or the previous value reconfirmed by a comprehensive or Group A test run before declaring the pump operable. The Owner shall determine whether the requirements of ISTB-3100, to reestablish reference values, apply. Deviations between the previous and new set of reference values shall be evaluated, and verification that the new values represent acceptable pump operation shall be placed in the record of tests (see ISTB-9000).
IV. Reason for Request On May 24, 2021, at 0915 Eastern Daylight Time (EDT), SQN Unit 1 experienced a reactor trip due to a control rod failure, which resulted in SQN Unit 1 entering Mode 3. The MDAFW Pump 1B-B started coincident with the reactor trip. At 1301 EDT on May 27, 2021, flames were observed coming out of the inboard pump bearing of the MDAFW Pump 1B-B. The pump was immediately secured and the flames were extinguished. SQN Unit 1 entered Technical Specification (TS) 3.7.5, Auxiliary Feedwater (AFW) System, Condition B, which requires that with one AFW train inoperable in Mode 1, 2, or 3, for reasons other than Condition A, then an AFW train must be restored to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. The 72-hour completion time expires at 1301 EDT on May 30, 2021. The cause of the failure of the MDAFW Pump 1B-B is still under investigation, but initial troubleshooting indicates an inboard bearing failure.
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Enclosure The MDAFW Pump 1B-B is being replaced and Owner review of ISTB-3310 determined that ISTB-3100 is applicable and a preservice test is required to develop a pump curve and establish new reference values and acceptance criteria before declaring the MDAFW Pump 1B-B operable. In accordance with SQN Unit 1 TS Limiting Condition for Operation (LCO) 3.0.4, MDAFW Pump 1B-B must be restored to operable status before the unit can transition from Mode 3 to a higher Mode. Therefore, the preservice test must be performed in Mode 3. The following information justifies why performing the preservice test in Mode 3 poses a hardship or unusual difficulty without a compensating increase in the level of quality and safety.
Currently, SQN Unit 1 is in Mode 3 with Tavg of 547.5 degrees Fahrenheit (°F), pressurizer level of 25 percent (%), and AFW flow of 100-125 gallons per minute (gpm) to maintain stable plant conditions due to low decay heat levels.
In order to perform the MDAFW Pump 1B-B pre-service test, flow from the MDAFW Pump 1B-B must be stabilized between 480 and 490 gpm for two minutes prior to data collection, then flow must be lowered to four other data point locations between full flow, and minimum flow for the pump. The 1B-B pump provides flow to Steam Generators (SG) 3 and 4 only. Cycling of flow to the SG is not desirable due to potential stresses placed on the SG nozzles. With such high flows required for extended durations for data collection on SG 3 and 4, flow must be isolated to SG 1 and 2 to provide sufficient time for the required data collection. Given that Unit 1 is in Mode 3, the SGs would be thermally cycled as the operators would most likely be required to repeatedly terminate the test to prevent loss of pressurizer level (as discussed below) and to maintain required SG levels below feedwater isolation setpoint of 81%.
In Mode 3 above permissive P-11, the pressurizer level is maintained below 30% due to inadvertent safety injection termination criteria requirements. The high AFW flows required by the preservice test could potentially cause letdown isolations on low pressurizer level as well as reactor coolant system (RCS) Tavg temperature drops. Letdown isolation will cause a rise in pressurizer level until operators can restore letdown potentially challenging the 30% level requirement.
Conversely, performance in Mode 1 allows sufficient reactor heat and main steam flow to support main feedwater flow. Flow from the MDAFW Pump is marginal in comparison to the flow volume from main feedwater. The SG level change from inducing full flow from one MDAFW Pump is controlled automatically by the main feed water regulating valves and main feed pump (MFP) speed controller (i.e., does not require operator action). The operator challenges of manual control of plant parameters are not necessary in Mode 1 due to the availability of the MFPs.
If the MDAFW Pump 1B-B is not able to be restored to operable status within the 72-hour Completion Time of SQN Unit 1 TS 3.7.5, Condition B, then SQN Unit 1 TS 3.7.5, Condition D would require the unit to transition from Mode 3 to Mode 4 within 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br />. Transition to Mode 4 is not a desirable operation from a plant transient aspect for the following reasons.
Maneuvering the plant from Mode 3 to lower modes of operation introduces additional shutdown risks, infrequent field and control room operations, and an increase in the volume of critical parameter monitoring. Cycling plant temperature and pressure from Mode 3 to Mode 4, and subsequently back to Mode 3 would introduce the potential to challenge both primary and secondary systems, such as safety valves simmering.
Performing this test in the lower mode of Mode 4 would present the same challenges in plant control during the test, but would actually result in more risk to the plant as it would first require CNL-21-059 E2 of 4
Enclosure the operators to maneuver the plant to Mode 4, perform the test, and then maneuver back to Mode 3 normal operating pressure and temperature to resume plant startup.
Based on simulator data, the preservice test could be performed in Mode 3; however, this would place the unit in a hardship with management of critical parameters of RCS temperature, SG level, and pressurizer level. Pressurizer pressure, pressurizer level, and SG levels have pre-established parameters that must be maintained outside of normal ranges to allow for full flow testing impacts. In addition, these parameters must be controlled manually because automatic controllers cannot maintain these parameters in band during test conditions. Even with ideal initial starting conditions and manual operator control, the test cannot be completed in its entirety without halting approximately every 20 minutes due to reaching maximum SG levels (70%) and requires approximately 100 minutes to drain back to initial conditions. There are five pump curve data points to be obtained during the full flow test. This risk cannot be eliminated and could only be mitigated by establishing clear abort criteria and performing just in time training.
Based on the above rationale, compliance with ISTB-3100 and ISTB-3310 represents a hardship or unusual difficulty without a compensating increase in the level of quality and safety.
Therefore, this request for alternative is being submitted in accordance with 10 CFR 50.55a(z)(2).
V. Proposed Alternative and Basis for Use Proposed Alternative Following the replacement of the MDAFWP Pump 1B-B, initial pump operability for compliance with TS LCO 3.7.5 and Surveillance Requirement (SR) 3.7.5.2 will be established by performance of a Group A pump test in Mode 3. The Group A pump test will be performed using the pump minimum flow recirculation path in which pump flow is set, then differential pressure and vibration are measured and compared to acceptance criteria established in accordance with ISTB-3300, ISTB-5121, and Table ISTB-5121-1. This acceptance criteria is truncated if necessary to ensure the pump minimum design limits are met.
The ISTB-3100 and ISTB-3310 required preservice test will be performed in Mode 1 during power ascension up to 95% power level, but no later than ten days from the performance of the Group A test. Testing will be performed in accordance with ISTB-3100, ISTB-3300, ISTB-5110, and Table ISTB-5121-1, as applicable. If the required preservice test is not performed within these timeframes, the unit will enter the required Action Statement of TS 3.7.5 Condition B.
Basis for Use SQN Unit 1 TS Bases for SR 3.7.5.2 state:
Verifying that each AFW pump's developed head at the flow test point is greater than or equal to the required developed head ensures that AFW pump performance has not degraded during the cycle. Flow and differential head are normal tests of centrifugal pump performance required by the ASME Code (Ref 2). Because it is undesirable to introduce cold AFW into the steam generators while they are operating, this testing is performed on recirculation flow. This test confirms one point on the pump design curve and is indicative of overall performance. Such inservice tests confirm component OPERABILITY, trend performance, and detect incipient failures by indicating abnormal performance. Performance of inservice CNL-21-059 E3 of 4
Enclosure testing discussed in the ASME Code (Ref. 2) (only required at 3 month intervals) satisfies this requirement.
The TS Bases provided above demonstrate the inservice test performed at the recirculation flow point on the pump design curve is adequate to confirm component operability. The TS SR and Bases do not place additional requirements on AFW pumps that have undergone repair, replacement, or routine servicing.
The performance of a Group A pump test is adequate to identify any significant issues resulting from replacement of the MDAFW Pump 1B-B and provides reasonable assurance that the MDAFW Pump 1B-B is capable of performing its safety-related function until plant conditions are stable enough to complete the ISTB-3310 required preservice test.
It should also be noted that the proposed alternative is consistent with recent ASME approved methodology in Section ISTB-3313, Baseline Test Deferral, of the ASME OM Code 2020 Edition.
VI. Duration of Proposed Alternative This alternative request is a one-time alternative request until the ISTB-3100 and ISTB-3310 required preservice test is completed for the MDAFW Pump 1B-B following SQN Unit 1 entering Mode 1.
VII. Precedents
- NRC letter to TVA dated August 26, 2019 (ML19227A110) approved a similar alternative request for the turbine driven auxiliary feedwater (TDAFW) pumps for SQN Units 1 and 2, and the Watts Bar Nuclear Plant (WBN), Units 1 and 2. The proposed alternative in Section IV of this alternative request is similar to the proposed alternative approved by the NRC for the TDAFW pumps in lieu of performing the ISTB-3310 required Group A comprehensive, or preservice test.
- A similar alternative (RR-4-12) was also approved by the NRC for Virgil C. Summer Nuclear Station, Unit 1 on April 28, 2017 (ML17088A256 and ML17103A533).
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