IR 05000327/2022010
| ML22115A161 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 04/25/2022 |
| From: | James Baptist NRC/RGN-II/DRS/EB1 |
| To: | Jim Barstow Tennessee Valley Authority |
| Shared Package | |
| ML22115A162 | List: |
| References | |
| IR 2022010 | |
| Download: ML22115A161 (14) | |
Text
April 25, 2022
SUBJECT:
SEQUOYAH NUCLEAR PLANT - DESIGN BASIS ASSURANCE INSPECTION (TEAMS) INSPECTION REPORT 05000327/2022010 AND 05000328/2022010
Dear Mr. Barstow:
On March 17, 2022, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Sequoyah Nuclear Plant and discussed the results of this inspection with Mr. Tom Marshall, Site Vice President and other members of your staff. The results of this inspection are documented in the enclosed report.
No findings or violations of more than minor significance were identified during this inspection.
This letter, its enclosure, and your response (if any) will be made available for public inspection and copying at http://www.nrc.gov/reading-rm/adams.html and at the NRC Public Document Room in accordance with Title 10 of the Code of Federal Regulations 2.390, Public Inspections, Exemptions, Requests for Withholding.
Sincerely, Signed by Baptist, James on 04/25/22 James B. Baptist, Chief Engineering Br 1 Division of Reactor Safety Docket Nos. 05000327 and 05000328 License Nos. DPR-77 and DPR-79
Enclosure:
As stated
Inspection Report
Docket Numbers: 05000327 and 05000328 License Numbers: DPR-77 and DPR-79 Report Numbers: 05000327/2022010 and 05000328/2022010 Enterprise Identifier: I-2022-010-0023 Licensee: Tennessee Valley Authority Facility: Sequoyah Nuclear Plant Location: Soddy Daisy, TN 37379 Inspection Dates: February 28, 2022 to March 18, 2022 Inspectors: C. Baron, Contractor J. Braisted, Reactor Inspector P. Braxton, Reactor Inspector R. Fanner, Reactor Inspector C. Franklin, Reactor Inspector P. Meier, Senior Resident Inspector R. Patterson, Senior Reactor Inspector S. Sandal, Senior Reactor Analyst T. Su, Reactor Inspector Approved By: James B. Baptist, Chief Engineering Branch 1 Division of Reactor Safety Enclosure
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting a design basis assurance inspection (teams) inspection at Sequoyah Nuclear Plant, in accordance with the Reactor Oversight Process. The Reactor Oversight Process is the NRCs program for overseeing the safe operation of commercial nuclear power reactors. Refer to https://www.nrc.gov/reactors/operating/oversight.html for more information.
List of Findings and Violations
No findings or violations of more than minor significance were identified.
Additional Tracking Items
None.
INSPECTION SCOPES
Inspections were conducted using the appropriate portions of the inspection procedures (IPs) in effect at the beginning of the inspection unless otherwise noted. Currently approved IPs with their attached revision histories are located on the public website at http://www.nrc.gov/reading-rm/doc-collections/insp-manual/inspection-procedure/index.html. Samples were declared complete when the IP requirements most appropriate to the inspection activity were met consistent with Inspection Manual Chapter (IMC) 2515, Light-Water Reactor Inspection Program - Operations Phase. The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel to assess licensee performance and compliance with Commission rules and regulations, license conditions, site procedures, and standards.
REACTOR SAFETY
===71111.21M - Design Bases Assurance Inspection (Teams) The inspectors evaluated the following components and listed applicable attributes, permanent modifications, and operating experience:
Design Review - Risk-Significant/Low Design Margin Components (IP Section 02.02) (5 Samples)
- (1) Unit 1 residual heat removal pump 1B-B Compliance with the Update Final Safety Analysis Report and the Technical Specifications Material condition and configuration Surveillance test procedures and recent results System health report Normal and emergency operating procedures Corrective action history
- (2) 480V Shutdown Boards 1A1-A,1B1-B, 1B2-B Compliance with UFSAR, TS and TS Bases Material Condition and Configuration Design Requirements Environmental Conditions Protective relay setting and calibration Overcurrent protection and coordination System Health Report
- (3) 1B EDG - Mechanical/Electrical Surveillance Test Procedures and Recent Results Corrective maintenance records Normal and Emergency Operating Procedures Vendor Manuals for battery chargers Condition Report history Alarm Response Procedures Design Procedures and Guides review Environmental Qualification Documents
- (4) Unit 1 Motor Driven Auxiliary Feedwater Pump 1B Normal and Emergency Operating Procedures Surveillance Test Procedures and Recent Results Inservice Test Procedures and Recent Results Basis for Pump Test Acceptance Criteria, Including Instrument Uncertainty Validation of Time Critical Action Associated with Isolating AFW Flow Safety and Seismic Classification of Piping Associated with AFW Pumps Potential Backleakage of Hot Fluid Through AFW Check Valves Potential Clogging of AFW Control Valves Material Condition of Pumps and Associated Equipment Corrective Action History
- (5) Unit 1 Pressurizer Power Operated Relief Valves (PORVs) SQN-1-PCV-068-0340A-A
& SQN-1-PCV-068-0334-B Normal and Emergency Operating Procedures Surveillance Test Procedures and Recent Results Time Critical Action Associated with PORVs Design Review - Large Early Release Frequency (LERFs) (IP Section 02.02) ===
- (1) Unit 1 Containment Purge/Relief Valves 1-FCV-30-46, -47, -48, -56, -57 Surveillance Test Procedures and Recent Results Appendix J Test Procedures and Recent Results Air-Operated Valve and Inservice Testing Program Documents Setpoint Control Calculations Valve and Actuator Vendor Manuals Environmental Qualification Documents Wiring, Logic, Control, and Flow Diagrams Preventive Maintenance History Corrective Action History
Modification Review - Permanent Mods (IP Section 02.03) (5 Samples)
- (1) DCN 22703, Replace Unit 1 TDAFW Governor Valve Controller w/Digital Controller
- (3) D23623, Degraded non-conforming motor-operated valve (MOV) modification for the gear replacement of the refueling water storage tank to residual heat removal pump control valve SQN-1-FCV-063-0001-A
- (4) DCN 23680, 480V Shutdown Board Transformer 1A1-A
- (5) D22644, Replace Pressurizer PORVs due to Current Valves Being Obsolete and Reaching End of Life
Review of Operating Experience Issues (IP Section 02.06) (4 Samples)
- (1) IN 2010-25 Inadequate Electrical Connections
- (2) IN 2019-08 Flow-Accelerated Corrosion Events
- (3) IN 2004-01: Auxiliary Feedwater Pump Recirculation Line Orifice Fouling - Potential Common Cause Failure
- (4) IN 84-06: Steam Binding of Auxiliary Feedwater Pumps
INSPECTION RESULTS
Very Low Safety Significance Issue Resolution Process: Safety Classification of 71111.21 Piping Associated with Auxiliary Feedwater Pump Suctions M This issue is a current licensing basis question and inspection effort is being discontinued in accordance with the Very Low Safety Significance Issue Resolution (VLSSIR) process. No further evaluation is required.
Description:
The inspectors identified a concern with the safety classification of a section of piping in the auxiliary feedwater (AFW) system. The water supply for the AFW pumps of both units is normally aligned from the two non-safety related, non-seismic condensate storage tanks (CSTs) through a common 16-inch header. The piping from the CSTs up to the auxiliary building wall is classified as TVA Class H. The Class H piping is not safety related, not seismically qualified, and not protected from external events.
The portion of piping from the auxiliary building wall to the check valves located adjacent to the six AFW pump suctions is classified as TVA Class G and Seismic Category I(L)A as defined in TVA Design Criteria Document SQN-DC-V-3.0, Classification of Piping, Pumps, Valves, and Vessels, Revision 23. The Class G piping is quality related, but not safety related, and is designed to designed to maintain pressure retention in the event of a safe shutdown earthquake (SSE). In accordance with SQN-DC-V-3.0, Category I(L)A seismic qualification may be accomplished without meeting the full extent of the design, construction, quality assurance, and other regulatory requirements normally specified for Seismic Category I structures, systems, or components wherein a quality related function must be assured. The remainder of the AFW system is classified as TVA Classes C and B.
The inspectors reviewed calculation CAD530HCGLCS110882, Auxiliary Feedwater System Pressure Switch Analytical Limits, Revision 18, which evaluated the automatic transfer of the AFW pumps suction supply from the CSTs to the safety related essential raw cooling water (ERCW) system. This transfer would be automatically initiated by low pressure switches in the CST supply header after a time delay. The AFW pumps would continue to operate during the transfer. The calculation took credit for the volume of water contained in a portion of the Class G piping after a seismic event; this volume was required to prevent air ingestion to the pump suctions during the time required to complete the transfer, less than one minute. If the Class G piping was not available, the transfer would not be successful without damaging the AFW pumps.
Based on these reviews, the inspectors were concerned with the classification of the Class G piping required to support the suction transfer. This portion of AFW system would be required to maintain pressure retention until the pump suction transfer was completed. SQN-DC-V-3.0, Table 3.1-1a addresses the classification of systems. Regarding AFW, it states that condensate supply and other piping not required after a seismic event but in Seismic Category I structures are TVA Class G, Seismic Category I(L). It also states that portions of the system not in SC-2a but required after a seismic event are TVA Class C, Seismic Category I. Based on calculation CAD530HCGLCS110882, the inspectors determined that this portion of piping would be required after a seismic event and should be TVA Class C, Seismic Category I in accordance with SQN-DC-V-3.0. The inspectors also observed that TVA Design Criteria Document SQN-DC-V-3.0 referenced NRC Regulatory Guide 1.26, Quality Group Classifications and Standards for Water ,Steam and Radioactive Waste Containing Components of Nuclear Power Plants, Revision 3, February, 1976; and that the design criteria document was consistent with the regulatory guide regarding safety classifications.
In response to this concern, the licensee stated that the classification of this piping was consistent with the licensing basis, was designed to maintain pressure retention in the event of a safe shutdown earthquake (SSE), was located within a safety related building, and was subject to periodic visual inspections in accordance with the Aging Management Program. They stated that this portion of the piping was only required to perform a secondary, not primary, safety function as discussed in Position 2 of NRC Regulatory Guide 1.29, Seismic Design Classification, Revision 2, February 1976.
After extensive discussions with licensee personnel and NRC staff, the inspectors concluded that there was very low safety significance associated with the difference between classifying this section of piping as TVA Class C, Seismic Category I and TVA Class G, Seismic Category I(L)A. The inspectors also concluded that the current licensing basis was not clear and significant resources would be required to fully resolve this issue.
Licensing Basis: UFSAR Table 10.4.7-5 states that AFW system components were classified in accordance with the draft version of ANS 18.2 issued August 1970 and that a point-by-point comparison with RG 1.26 quality groups shows no significant differences for the AFW.
UFSAR Section 3.7.3.6, Seismic Analysis of System Piping, states All piping systems important to safety that have been designed to remain functional in the event of a safe shutdown earthquake (SSE) are designated as Category I.
Those portions of structures, systems, or components which perform secondary safety functions and which are not essential to safe shutdown and isolation of the reactor but whose failure could jeopardize, to an unacceptable extent, the achievement of a primary safety function are considered Category I(L) safety related.
Where pressure boundary integrity is required, the piping is classified as Category I(L)A. For Category I(L)A, all piping and tubing shall be analyzed to meet the requirements for Category I except that ASME Section III subsection NC Equation 9 needs not to be evaluated for the upset condition.
UFSAR Table 10.4.7-6, Responses to Short- and Long-Term Recommendations Resulting From a General NRC Investigation of AFWS, states that pump damage is prevented by the automatic transfer to the alternate water source which is essential raw cooling water.
Significance: This potential issue would Phase 1 screen to GREEN in question 1 of exhibit 2 (for mitigating systems - AFW) of IMC 0609 App A because there is no increased likelihood of failure of the pipe due to the qualification in question (i.e., no change in PRA likelihood of failure between the nominal and conditional case).
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
On March 17, 2022, the inspectors presented the design basis assurance inspection (teams) inspection results to Mr. Tom Marshall, Site Vice President and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection Type Designation Description or Title Revision or
Procedure Date
71111.21M Calculations 03D53EPMGLC031193 Condensate Storage Tank (CST) Usable Volume for Rev. 10
Aux Feedwater Use
03D53EPMWLL063094 AFW Hydraulic Analysis Rev. 17
219280000 Minimum Head Required for the Turbine-Driven and Rev. 26
Motor Driven Auxiliary Feedwater (AFW) Pumps
219280000A Flow to Steam Generator During Main Steam Line Rev. 15
Break for Various Single Component Failures
3BD53HCGHCM090486 Auxiliary Feedwater System Maximum Operating Rev. 18
Pressures
B25861217301 7-Day Fuel Oil Tank Volume & Setpoints Calculation - Rev. 7
Diesel Generators
B87 890810 003 SQN Diesel Generator Fuel Oil Consumption 7 Day Rev. 3
Supply Calculation
CAD0530HCGLCS032384 Auxiliary Feedwater System Instrument/Process Safety Rev. 24
Limits
CAD530HCGLCS110882 Auxiliary Feedwater System Pressure Switch Analytical Rev. 20
Limits
ED00009992018000092 Turbine Driven Auxiliary Feedwater Dedication, Rev. 0
Qualification, and Software Verification &
Validation Documentation
MDQ00000120020128 System Level Review for Sequoyah Main Steam Rev. 0
Supply System (MSSS) Air Operated Valves (AOV)
MDQ00000120020133 Evaluation of Required Thrust for MSIVs and SG- Rev. 1
PORVs (Pilot-Operated Balanced Disk Globe AOVs) At
Sequoyah Nuclear Power Station
MDQ00000120020134 Component Level Review Calculation for SQN Main Rev. 5
Steam Supply (MSS) System Pilot-Operated Balanced
Disk Globe Air Operated Valves (AOVs)
MDQ00099920040148 Set Point Controls Parameters Review Calculation for Rev. 10
Sequoyah Category 2 Air Operated Valves (AOVs)
SCG-4M-00976 Seismic Qualification of 32" Main Steam Isolation Rev. 4
Valve
Inspection Type Designation Description or Title Revision or
Procedure Date
SQN-APS-003 480VAC APS Class 1E Load Coordination Study Rev. 115
SQN-CPS-051 Circuit Protection Device Evaluation Rev. 74
SQNETAPAC Auxiliary Power System Rev. 111
SQS20110 Emergency and Abnormal Operating Procedure Rev. 40
Setpoints
SQTP-003 ASME Section XI ln-service and Augmented Valve Rev. 042
Identification for the Second and Third Ten
Year Interval
Corrective Action Condition Report (CR) 1210327, 1494201, 1557491, 1560137, 1561929,
Documents 1687020, 1697239, PER 20333
Corrective Action 1758304 Administrative Drawing Discrepancies Were Identified
Documents When Responding to an NRC Question
Resulting from 1758706 Procedure Weakness Was Identified When
Inspection Responding to a Question Asked By an NRC Inspector
1759019 SQN DBAI 2022010 / DWG 1-47W610-30-1 03/03/2022
Discrepancy
1759352 5/28/21 performance of 1-SI-SXP-003-202.B, Motor
Driven Auxiliary Feedwater Pump 1B-B
Comprehensive Performance Test
1759354 11/8/21 performance of 1-SI-SXP-003-201.B, Motor
Driven Auxiliary Feedwater Pump 1B-B Performance
Test
1759382 During Extent of Condition Review, an EOP Weakness
Was Identified
1759385 During the Extent of Condition Review, Additional
Deficiencies In PI-4 Were Identified
1760059 SQN DBAI 2022010 / Revise 0-MI-MVV-000-022.0 and 03/07/2022
MMTP-152
1760945 NRC Asked Whether If It Necessary to Consider Flow
As Part Of The Overall Uncertainty For The IST Pump
Flow Tests
1762821 SQN Should Consider Using AFW Discharge Header
Temperature Elements to Monitor for Backleakage
Through AFW Check Valves
Inspection Type Designation Description or Title Revision or
Procedure Date
CR 1761999 ECP 22703 TDAFW flow controller dead time not 03/14/2022
exeplicity discussed in 50.59
Drawings 1,2 45N749-4 Wiring Diagram 480V shutdown Board 1B2-B Single Rev. 63
Line
1,2- 45N749-1 Wiring Diagrams 480 V SD Board 1A1-A Single Line Rev. 54
1,2- 45N749-3 Wiring Diagram 480V Shutdown Board 1B1-B Single Rev. 58
Line
1,2-45N630-11, Sht. 11 Wiring Diagrams, Ventilation System Schematic Rev. 9
1,2-47W611-30-1 Mechanical Logic Diagram, Ventilation System Rev. 4
1,2-47W801-1 Flow Diagram, Main & Reheat Steam Rev. 122
1,2-47W866-3 Auxiliary Building -Flow Diagram Heating Vent & Air Rev. 20
Cond Air Flow
1-3591A16 Breaker Setting Sheet 480V Shutdown BD 1B1 Rev. 5
1-3591A17 Breaker Setting Sheet 480V Shutdown BD 1B1-B Rev. 5
1-47W610-30-1 Mechanical Control Diagram, Cntmt Ventilation Sys Rev. 23
1-47W866-1 Flow Diagram, Heating and Ventilating Air Flow Rev. 43
SQN-0-45N779-23 Wiring Diagram - 480V Shutdown Aux Power Rev. 44
Schematic Diagram SH-23
SQN-0-45N779-49 Wiring Diagram - 480V Shutdown Aux Power Rev. 4
Schematic Diagram SH-49
SQN-0-47W427-3 Mechanical Auxiliary Feedwater Piping Rev. 5
SQN-0-47W427-4 Mechanical Auxiliary Feedwater Piping Rev. 12
SQN-0-47W611-3-3 Mechanical Logic Diagram - Auxiliary Feedwater Rev. 44
System
SQN-0-47W803-2 Flow Diagram - Auxiliary Feedwater Rev. 78
SQN-0-47W813-1 Flow Diagram - Reactor Coolant System Rev. 59
SQN-1-47W610-3-3 Mechanical Control Diagram - Auxiliary Feedwater Rev. 32
System
SQN-2-47K427-59 N2-03-10A Isometric - Auxiliary Feedwater Piping Rev. 4
Engineering DC 22703 Upgrade the Turbine Driven Auxiliary Feedwater Rev. 2
Changes Speed Governor and Flow Controller
Miscellaneous Equipment Failure Investigation Checklist - Unit 1, B dated
Train Motor Driven Auxiliary Feed Water Pump Failure 08/20/21
Inspection Type Designation Description or Title Revision or
Procedure Date
Sequoyah Nuclear Plant Updated Final Safety Analysis Amend. 29
Report
0-GO-14-1 Daily Logsheet Rev. 55
0-TI-SXI-000-100.0 Inservice Testing Program Bases Document Rev. 6
0-TI-SXI-000-200.0 Inservice Testing Program Rev. 7
Amendment No. 61 Deletion of Reference to Motor-Operated Valves dated
(MOVs) With Bypassed Thermal Overload Devices and 10/22/87
Other MOVs
Part 21, Event Number INTROL POSITIONERS POTENTIAL LATENT 05/31/2019
54095 DEFECT
SO-22-007 Standing Order - Isolation of AFW to a Faulted S/G dated
03/02/22
SQN-DC-V-13.9.5 Reactor Building Environmental Control System Rev. 9
SQN-DC-V-21.0 Environmental Design Rev.29
SQN-DC-V-4.1.1 Main Steam System Rev. 19
SQN-VTD-A585-0020 Instruction Manual for 32 Main Steam Isolation Valves Rev. 10
SQN-VTD-B237-0020 General Operating and Maintenance Instructions Rev. 1
Double Acting and Spring Return Series Pneumatic
Rotary Valve Actuators
SQN-VTD-B237-0030 General Operating and Maintenance Instructions for Rev. 1
Nuclear Series Actuators
SQN-VTD-B237-0070 Operating and Maintenance Instructions Disassembly Rev. 2
and Assembly Spring Return Series Actuators
SQN-VTD-F130-1300 Fisher Controls 67C Series Instrument Supply Rev. 1
Regulators
SQN-VTD-W120-7457 MPH-DS Breaker (MARCH, 1999) Maintenance Rev. 5
Program Manual for Safety Related Type DS Low
Voltage Metal Enclosed Switchgear
Procedures 0-PI-DXX-000-100.06.2 Uninsulated Components External Surfaces Inspection Rev. 5
0-PI-OPS-000-004.0 Periodic Validation of Time Critical Actions Using Rev. 15
Simulator
0-SI-SLT-030-258.3 Containment Isolation Valve Local Leak Rate Test Rev. 12
Containment Vacuum Relief
0-SI-SXV-068-201.0 Pressurizer PORV Operability Test Rev. 2
Inspection Type Designation Description or Title Revision or
Procedure Date
0-TI-DXX-000-016.0 Erosive Wear Degradation Monitoring Program Rev. 3
0-TI-OPS-000-004.0 Time Critical Operator Actions Rev. 11
0-TI-OPS-000-004.0 Time Critical Operator Actions Rev. 11
0-TI-SXI-000-200.0 Inservice Testing Program Rev. 7
0-TPP-DXX-000-100.06 License Renewal Aging Management Program Basis Rev. 2
Document External Surfaces Monitoring Program
1-SI-ICC-003-144.0 Calibration of Condensate Storage Tank Suction Rev. 14
Header Pressure Switches to Auxiliary Feedwater
System (1-PS-3-144A, -144B & -144D)
1-SI-ICC-003-144.0 Calibration of Condensate Storage Tank Suction Rev. 14
Header Pressure Switches to Auxiliary Feedwater
System
1-SI-OPS-003-118.0 Auxiliary Feedwater Pump and Valve Automatic Rev. 38
Actuation
1-SI-SXP-003-201.B Motor Driven Auxiliary Feedwater Pump 1B-B dated
Performance Test 02/08/22
1-SI-SXP-003-202.B Motor Driven Auxiliary Feedwater Pump 1B-B dated
Comprehensive Performance Test 05/28/21
1-SI-SXV-000-201.0 Full Stroking of Category A and B Valves During Rev. 28
Operation
1-SO-3-2 Auxiliary Feedwater System Rev. 62
DS-M4.2.1 Flow Accelerated Corrosion Program Methods Rev. 10
E-0 Reactor Trip or Safety Injection Rev. 43
E-0 Reactor Trip or Safety Injection Rev. 43
E-1 Loss of Reactor or Secondary Coolant Rev. 32
E-3 Steam Generator Tube Rupture Rev. 28
EA-202-2 Operating Equipment from 6.9KV Shutdown Board Rev. 0
EA-3-10 Establishing Motor Driven AFW Flow Rev. 5
EA-3-11 Local Isolation of MD and TD AFW Rev. 2
ECA-0.0 Loss of All AC Power Rev. 37
ES-1.3 Transfer to RHR Containment Sump Rev. 24
ES-1.4 Transfer to Hot Leg Recirculation Rev. 7
NPG-SPP-09.18.1 Vulnerability Identification and Rev. 10
Inspection Type Designation Description or Title Revision or
Procedure Date
Management
NPG-SPP-09.26.13 Air Operated Valve Program Rev. 1
NPG-SPP-09.7.2 Flow Accelerated Corrosion Control Program Rev. 5
NPG-SPP-09.7.5 Erosion Program Rev. 1
SAR Change 20-27 Increased Operator Action Times for a SGTR dated
06/02/06
SQN-DC-V-13.9.8 Auxiliary Feedwater System Rev. 30
SQN-DC-V-27.4 Reactor Coolant System Rev. 26
SQN-DC-V-3.0 The Classification of Piping, Pumps, Valves, and Rev. 23
Vessels
Work Orders Work Order (WO) 111338695, 119443478, 119446769, 119746807,
20281971, 120440234, 120792667, 120883320,
21401831, 121135517, 121135880, 121446977,
21721612, 121881329, 121912740, 121919585,
21982107, 122040836, 122062181, 118860328,
118860343, 120231713,
21719840, 120573157
2