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
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, 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:
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
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 Piping Associated with Auxiliary Feedwater Pump Suctions 71111.21 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
Procedure
Type
Designation
Description or Title
Revision or
Date
03D53EPMGLC031193
Condensate Storage Tank (CST) Usable Volume for
Aux Feedwater Use
Rev. 10
03D53EPMWLL063094
AFW Hydraulic Analysis
Rev. 17
219280000
Minimum Head Required for the Turbine-Driven and
Motor Driven Auxiliary Feedwater (AFW) Pumps
Rev. 26
219280000A
Flow to Steam Generator During Main Steam Line
Break for Various Single Component Failures
Rev. 15
3BD53HCGHCM090486
Auxiliary Feedwater System Maximum Operating
Pressures
Rev. 18
B25861217301
7-Day Fuel Oil Tank Volume & Setpoints Calculation -
Diesel Generators
Rev. 7
B87 890810 003
SQN Diesel Generator Fuel Oil Consumption 7 Day
Supply Calculation
Rev. 3
CAD0530HCGLCS032384
Auxiliary Feedwater System Instrument/Process Safety
Limits
Rev. 24
CAD530HCGLCS110882
Auxiliary Feedwater System Pressure Switch Analytical
Limits
Rev. 20
ED00009992018000092
Turbine Driven Auxiliary Feedwater Dedication,
Qualification, and Software Verification &
Validation Documentation
Rev. 0
MDQ00000120020128
System Level Review for Sequoyah Main Steam
Supply System (MSSS) Air Operated Valves (AOV)
Rev. 0
MDQ00000120020133
Evaluation of Required Thrust for MSIVs and SG-
PORVs (Pilot-Operated Balanced Disk Globe AOVs) At
Sequoyah Nuclear Power Station
Rev. 1
MDQ00000120020134
Component Level Review Calculation for SQN Main
Steam Supply (MSS) System Pilot-Operated Balanced
Disk Globe Air Operated Valves (AOVs)
Rev. 5
MDQ00099920040148
Set Point Controls Parameters Review Calculation for
Sequoyah Category 2 Air Operated Valves (AOVs)
Rev. 10
Calculations
SCG-4M-00976
Seismic Qualification of 32" Main Steam Isolation
Valve
Rev. 4
Inspection
Procedure
Type
Designation
Description or Title
Revision or
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
Setpoints
Rev. 40
SQTP-003
ASME Section XI ln-service and Augmented Valve
Identification for the Second and Third Ten
Year Interval
Rev. 042
Corrective Action
Documents
Condition Report (CR)
210327, 1494201, 1557491, 1560137, 1561929,
1687020, 1697239, PER 20333
1758304
Administrative Drawing Discrepancies Were Identified
When Responding to an NRC Question
1758706
Procedure Weakness Was Identified When
Responding to a Question Asked By an NRC Inspector
1759019
SQN DBAI 2022010 / DWG 1-47W610-30-1
Discrepancy
03/03/2022
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
MMTP-152
03/07/2022
1760945
NRC Asked Whether If It Necessary to Consider Flow
As Part Of The Overall Uncertainty For The IST Pump
Flow Tests
Corrective Action
Documents
Resulting from
Inspection
1762821
SQN Should Consider Using AFW Discharge Header
Temperature Elements to Monitor for Backleakage
Through AFW Check Valves
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
CR 1761999
ECP 22703 TDAFW flow controller dead time not
exeplicity discussed in 50.59
03/14/2022
1,2 45N749-4
Wiring Diagram 480V shutdown Board 1B2-B Single
Line
Rev. 63
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
Line
Rev. 58
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
Cond Air Flow
Rev. 20
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
Schematic Diagram SH-23
Rev. 44
SQN-0-45N779-49
Wiring Diagram - 480V Shutdown Aux Power
Schematic Diagram SH-49
Rev. 4
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
System
Rev. 44
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
System
Rev. 32
Drawings
SQN-2-47K427-59
N2-03-10A Isometric - Auxiliary Feedwater Piping
Rev. 4
Engineering
Changes
DC 22703
Upgrade the Turbine Driven Auxiliary Feedwater
Speed Governor and Flow Controller
Rev. 2
Miscellaneous
Equipment Failure Investigation Checklist - Unit 1, B
Train Motor Driven Auxiliary Feed Water Pump Failure
dated
08/20/21
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Sequoyah Nuclear Plant Updated Final Safety Analysis
Report
Amend. 29
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
(MOVs) With Bypassed Thermal Overload Devices and
Other MOVs
dated
10/22/87
Part 21, Event Number 54095
INTROL POSITIONERS POTENTIAL LATENT
DEFECT
05/31/2019
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
Double Acting and Spring Return Series Pneumatic
Rotary Valve Actuators
Rev. 1
SQN-VTD-B237-0030
General Operating and Maintenance Instructions for
Nuclear Series Actuators
Rev. 1
SQN-VTD-B237-0070
Operating and Maintenance Instructions Disassembly
and Assembly Spring Return Series Actuators
Rev. 2
SQN-VTD-F130-1300
Fisher Controls 67C Series Instrument Supply
Regulators
Rev. 1
SQN-VTD-W120-7457
MPH-DS Breaker (MARCH, 1999) Maintenance
Program Manual for Safety Related Type DS Low
Voltage Metal Enclosed Switchgear
Rev. 5
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
Simulator
Rev. 15
0-SI-SLT-030-258.3
Containment Isolation Valve Local Leak Rate Test
Containment Vacuum Relief
Rev. 12
Procedures
0-SI-SXV-068-201.0
Pressurizer PORV Operability Test
Rev. 2
Inspection
Procedure
Type
Designation
Description or Title
Revision or
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
Document External Surfaces Monitoring Program
Rev. 2
1-SI-ICC-003-144.0
Calibration of Condensate Storage Tank Suction
Header Pressure Switches to Auxiliary Feedwater
System (1-PS-3-144A, -144B & -144D)
Rev. 14
1-SI-ICC-003-144.0
Calibration of Condensate Storage Tank Suction
Header Pressure Switches to Auxiliary Feedwater
System
Rev. 14
1-SI-OPS-003-118.0
Auxiliary Feedwater Pump and Valve Automatic
Actuation
Rev. 38
1-SI-SXP-003-201.B
Motor Driven Auxiliary Feedwater Pump 1B-B
Performance Test
dated
2/08/22
1-SI-SXP-003-202.B
Motor Driven Auxiliary Feedwater Pump 1B-B
Comprehensive Performance Test
dated
05/28/21
1-SI-SXV-000-201.0
Full Stroking of Category A and B Valves During
Operation
Rev. 28
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
Transfer to RHR Containment Sump
Rev. 24
Transfer to Hot Leg Recirculation
Rev. 7
NPG-SPP-09.18.1
Vulnerability Identification and
Rev. 10
Inspection
Procedure
Type
Designation
Description or Title
Revision or
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
Rev. 26
SQN-DC-V-3.0
The Classification of Piping, Pumps, Valves, and
Vessels
Rev. 23
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