IR 05000348/2020010
| ML21015A000 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 01/14/2021 |
| From: | James Baptist Division of Reactor Safety II |
| To: | Kharrl C Southern Nuclear Operating Co |
| References | |
| IR 2020010 | |
| Download: ML21015A000 (14) | |
Text
January 14, 2021
SUBJECT:
JOSEPH M. FARLEY NUCLEAR PLANT - DESIGN BASIS ASSURANCE INSPECTION (PROGRAMS) INSPECTION REPORT 05000348/2020010 AND 05000364/2020010
Dear Mr. Kharrl:
On December 9, 2020, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Joseph M. Farley Nuclear Plant and discussed the results of this inspection with Delson Erb 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,
/RA/
James B. Baptist, Chief Engineering Br 1 Division of Reactor Safety
Docket Nos. 05000348 and 05000364 License Nos. NPF-2 and NPF-8
Enclosure:
As stated
Inspection Report
Docket Numbers:
05000348 and 05000364
License Numbers:
Report Numbers:
05000348/2020010 and 05000364/2020010
Enterprise Identifier: I-2020-010-0039
Licensee:
Southern Nuclear Operating Co., Inc.
Facility:
Joseph M. Farley Nuclear Plant
Location:
Columbia, AL
Inspection Dates:
April 06, 2020 to December 09, 2020
Inspectors:
P. Braxton, Reactor Inspector
M. Donithan, Operations Engineer
P. Niebaum, Senior Project Engineer
R. Patterson, Senior Reactor Inspector
S. Sandal, Senior Reactor Analyst
M. Schwieg, Reactor Inspector
M. Yeminy, contractor
S. Kobylarz, contractor
Approved By:
James B. Baptist, Chief
Engineering Br 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 (programs) inspection at Joseph M. Farley 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.
Starting on March 20, 2020, in response to the National Emergency declared by the President of the United States on the public health risks of the coronavirus (COVID-19), inspectors were directed to begin telework. In addition, regional baseline inspections were evaluated to determine if all or portion of the objectives and requirements stated in the IP could be performed remotely. If the inspections could be performed remotely, they were conducted per the applicable IP. In some cases, portions of an IP were completed remotely and on site. The inspections documented below met the objectives and requirements for completion of the IP
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) (6 Samples)
- Material condition and installed configuration (e.g., visual inspection/walkdown)
- Normal, abnormal, and emergency operating procedures
- Consistency among design and licensing bases and other documents/procedures
- Maintenance effectiveness and records, and corrective action history
- Design calculations
- Surveillance testing and recent test results
- System and component level performance monitoring
- Consistency among design and licensing bases and other documents/procedures
- System and component level performance monitoring
- Diaphragm installation and maintenance
- (1) Unit 1 and Unit 2 Auxiliary Feed Water System including the Turbine Driven Auxiliary Feed Water (TDAFW) Pump and AFW check valves (N23V002A/B and N23V002D/F/H)
- (2) Startup Auxiliary Transformers 1A, 1B, 2A, and 2B (3)1K/1L Feeder breakers (DF02/DG02)
- (4) Unit 1 and Unit 2 Condensate Storage Tanks
- (5) Emergency Diesel Generator (EDG) 1C room ventilation
- (6) EDG Fuel Oil Transfer Pumps
Design Review - Large Early Release Frequency (LERFs) (IP Section 02.02)===
- (1) Unit 1 and Unit 2 Reactor Coolant Pump (RCP) Shut Down Seals
- Normal, abnormal and emergency operating procedures
- Maintenance effectiveness; Maintenance Rule functions and performance criteria, procedures for preventive maintenance, inspection, and seal replacement to compare maintenance practices against industry and vendor guidance.
- Component health reports, corrective maintenance records, and corrective action history
- Failure mode analysis of RCP shutdown seal components
Modification Review - Permanent Mods (IP Section 02.03) (4 Samples)
- (1) DG02 Breaker Hand Switch Q2R15HS2007BA Replacement
- (2) SNC929182, 4kV Switchgear Bus 1K Lightning Arrestor Power Cable - 1VADF02Q
- (3) SNC808954, Unit 1 Train A 4.16 kV Breaker Replacement
- (4) SNC875753, CRACS Motor Controller Replacement for 2A, 2B, and 3A
Review of Operating Experience Issues (IP Section 02.06) (1 Sample)
- (1) IN-18-04, Operating Experience Regarding Failure of Operators to Trip the Plant When Experiencing Unstable Conditions.
INSPECTION RESULTS
Very Low Safety Significance Issue Resolution Process: Capability of Emergency Diesel Building (EDB) Ventilation System to Withstand the Effects of a Tornado 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 DBAI inspectors identified an issue of concern in that the EDGs ventilation systems were not specifically shown to be designed to withstand the effects of a tornado depressurization. A tornado pressure drop could potentially damage all EDB exhaust fans and cause failure of all the FNP EDGs ability to maintain its safety functions due to rapidly increasing room temperatures.
There are two EDB ventilation subsystems: generator room and switchgear room. The generator room ventilation system maintains a maximum temperature 122F during the generator operation cycle. The switchgear room ventilation system maintains a maximum temperature of 104F.
The generator rooms ventilation systems consist of one small power roof exhaust ventilator and two large power roof exhaust ventilator in each room (each 100 percent capable units),one motor-operated wall air intake louver in each room for supplying air to the exhaust ventilators, and annunciation equipment for alarming the control room in the event of excessively high or low temperatures within the rooms.
The switchgear rooms ventilation systems include in each room a power roof exhaust ventilator, a nonpowered roof exhaust ventilator, and a power roof intake ventilator with connecting ductwork and redundant motor-operated dampers. Both the power intake and power exhaust ventilators are sized to individually provide 100 percent of the heat removal requirements and are totally redundant, and annunciation equipment for alarming the control room in the event of excessively high or low temperatures in the rooms.
In April 2017, the licensee performed a safety system functional assessment on the EDGs, it was identified that the motor-operated wall air intake louver in each EDG room did not specifically account for the expected differential pressure for a design basis tornado. The design basis tornado as defined in the site USFAR has a maximum wind speed of 300 mph and a pressure drop of 3.0 psi over a 3.0 sec period. Procedure FNP-0-AOP-21.0 Severe Weather was revised to require placing one roof ventilation fan in each EDG room in service to ensure the wall air intake louvers were in the open position to facilitate equalization of the differential pressure. This action would occur if a tornado watch was issued for the site.
During the DBAI inspection, the inspectors questioned the technical bases for the procedural change to ensure that the actions incorporated into procedures FNP-0-AOP-21.0 and FNP-0-SOP-43.0 were appropriate. The site provided an information-only calculation to show that the actions incorporated into the procedure were sufficient enough to prevent damage to the exhaust ventilators and louvers in the EDG room but it did not account for the impacts on the switchgear rooms.
The inspectors reviewed this calculation and identified the square footage input for the corridor entry ways was less due to the security door and corridor grating. When the inspectors independently evaluated the calculation using the reduced corridor area, the EDG room and switchgear room exhaust ventilators could potentially be damaged during a design basis tornado event.
The licensee provided another calculation using Regulatory Guide 1.76 (issued in March 2007) which revised the design-based tornado characteristics based on geographical regions. Plant Farley is in Region I so the revised characteristics were wind speed of 230 mph and 1.2 pressure drop over 2.4 seconds. The licensee determined the EDG roof ventilators would not be damaged with the revised tornado characteristics. However, the inspectors determined the switchgear room roof ventilators could be damaged.
The inspectors reviewed the operator action to start one EDG room ventilator after a tornado watch is issued. This action will open the EDG room air intake louvers. If the operator failed to complete this action or a tornado watch was not issued, the EDG room louvers would not be opened. This condition would prevent pressure equalization through the corridor and have an impact on the EDG room exhaust ventilators. The inspectors evaluated other tornado characteristics and determined a tornado equivalent to a Region II with a maximum wind speed of 200 mph could damage the EDG room exhaust ventilators if the operator action was not completed.
The inspectors reviewed the EDG building calculation (2142-AH-003, Design Generator Building Concrete Calculations, 3/11/87) demonstrate that the DG portions of the building are sufficiently ventilated such that the depressurization effects would be negligible. This was demonstrated by meeting criteria in Bechtel design Topical Report BC-TOP-3-A (ML14093A218) which concluded that no significant pressure differential develops if there is a minimum of 1 FT2 of vent area to 1000 FT3 of room volume. Calculation 2142-AH-003 utilizes the Hatch Nuclear Plant DG building as the structure and ventilation input which provides a very similar structure and ventilation equipment layouts as the Farley design. The Hatch DG building has the same layout feature as Farley where a large corridor with grating air intakes one each end provides protection of each DG rooms ventilation intake dampers and personnel access doors from missiles and wind loading.
The calculation determined the DG rooms have adequate ventilation openings suitable to be classified as fully vented. However, the DG switchgear rooms were determined to be only partially vented and a depressurization computer run was performed. The results of the DG switchgear room depressurization indicate structure would not be in jeopardy. Observation of the structural calculation depressurization results indicates the differential pressure challenge to the ventilation fan and ductwork would be reduced to approximately 0.3 psi.
The inspectors questioned the conclusion that no significant pressure differential develops in the EDB rooms. The corridor entry dimensions did not consider the loss of area due to the doors and grating. If the reduce corridor area was used, the fully vented criteria (1 FT2 of vent area to 1000 FT3 of room volume.) would not be met and a further analysis would be required. Farley switchgear room have a different layout from Hatch EDB. Farley has two large switchgear room while Hatch has five smaller switchgear room. The Farley layout would create a larger differential pressure during a tornado de-pressurization and it could impact the switchgear fans.
The inspectors could not determine if Farleys EDB ventilation design was based on this calculation or whether significant differential pressure would develop in the EDB rooms without further analysis.
The inspectors evaluated the impact of the loss of the switchgear room roof ventilators and determined the condition was recoverable. Since the switchgear generates less heat, it would take several hours before a high temperature room alarm would occur. The operators would have enough time to take compensatory actions by installing temporary room fans.
The inspectors evaluated the impact of loss of the EDG room roof ventilators and determine the condition was unrecoverable. If the EDG roof exhaust ventilators were damaged, a running EDG could overheat within an hour. Given the size of these ventilator fans (56,200 CFM), the operators could not install temporary fans to remove the running EDG room heat. This could result in a complete loss all onsite emergency power
Following the inspectors identification of the concern, the licensee entered the issue into their corrective action program as nuclear condition report NCR 10704499, and took additional actions to inspect the fans and dampers following a tornado event.
Licensing Basis: The NRC staff reviewed both current and historical regulatory requirements and regulatory correspondence related to the EDB tornado protection criterion. The main documents reviewed are detailed below.
- USFAR sections 3.2.1, 3.3.2 and Table 3.2-1
- 10 CFR 50, Appendix A, Criterion 2Design bases for protection against natural phenomena.
- 10 CFR 50, Appendix B, Criterion III, Design Control,
- Regulatory Issue Summary (RIS) 2006-23
- Regulatory Issue Summary (RIS) 2015-06
- Regulatory Guide 1.76 (issued in March 2007)
The inspectors were not able to conclude whether the issue of concern was part of the plants current licensing basis. As a result, the effort to determine whether the EDG ventilation systems should be protected from the effects of a tornado depressurization is judged to likely require a significant amount of resources to develop a conclusion that far outweighed the issues potential safety significance.
As a result, the issue could be closed without immediate enforcement action and treated under the very low safety significance issue resolution process.
Significance: A risk evaluation was performed by a regional senior reactor analyst using SAPHIRE Version 8.2.2 and NRC Farley SPAR model Version 8.57. The conditional analysis assumed failure of the EDG ventilation fans for tornado initiating events with wind speeds greater than 200 miles per hour with a one-year exposure time. The dominant sequences were a tornado initiator accompanied by a loss of offsite power with failures of the emergency diesel generators, the turbine driven AFW pump, and operator actions to recover offsite power. The analysis determined that if a performance deficiency was assumed to have existed, it would have resulted in an increase in core damage frequency of <1E-6/year, representing very low safety significance (Green).
Technical Assistance Request: A technical assistance request (TAR) was not initiated.
Corrective Action Reference: NCR
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On December 9, 2020, the inspectors presented the design basis assurance inspection (programs) inspection results to Delson Erb and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
71111.21M Calculations
Revised tornado depressurization model
38.04
Unit 2 Verification of AFW Flow Bases
40.02
Unit 1 Verification of AFW Flow Bases
E-035.02.A
Setting of Protective Relays for 4.16kV Auxiliary Power
System
Rev.8
Calibration
Records
FNP-BFM-007
Data Sheet 7, Maintenance Test Gauge and Flowmeter
Calibration in Support of Units 1 and 2 STP-158
4.0
Corrective Action
Documents
10364209
Time Critical Operator Actions periodic validation
results from training segment 17-3
05/11/2017
10540234, 10547916,
731598, 753172, 807775,
10487968, 10495824,
10601538, 1057275,
10616812, 10660702,
10656967, 10475772,
10601078
10698360
Tracking and trending of Time Critical Operator Action
Program periodic validation
03/25/2020
CARs 276841, 273775
Corrective Action
Documents
Resulting from
Inspection
10703532
- This is a place holder fro Stan's procedure
discrepancies
CR 10703089
DBAI NRC identified - NMP-OS0014-001 TCOA E04
(Response to Security Event)
04/21/2020
CR 10703095
DBAI NRC identified - NMP-OS0014-001 TCOA E16
04/21/2020
CR10704499
NRC identified FNP-0-SOP-43.0
04/22/2020
CR10732049
NRC minor violation - transformer loading
8/21/2020
CR10732057
NRC Minor Violation - Testing Rig Accuracy
08/21/2020
CRs 10706041, 10700974
Drawings
C-172765
Elementary Diagram - 4160 V Bus 1K Feeder Breaker
to Station Service Transformer 1K
Rev. 7
D-172747
Elementary Diagram - Service Water Pump No. 1A -
Rev.12
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Bus 1K
D-172748
Elementary Diagram - Service Water Pump No. 1B -
Bus 1K
Rev. 13
D-172749
Elementary Diagram - Service Water Pump No. 1C -
Bus 1K
Rev. 14
D-172948
Wiring Diagram - 4160 Volt Switchgear Bus 1K Cell
No. DK01, Sheet. 1
Rev. 7
D-173013
Outdoor AC Distribution Cabinet (Low Voltage
Switchgear)
Rev. 5
D-175007
Unit 1 Auxiliary Feedwater System Piping and
Instrumentation Diagram (PI&D)
D-175033
Unit 1 P&ID - Main Steam and Auxiliary Steam
Systems
D-177001
Single Line Electrical Auxiliary System (Emergency
4160 & 600 V), Sheet. 1
Rev. 23
Engineering
Changes
SNC1012405
Breaker DG02 Remote Handswitch Replacement
Q2R15HS2007BA
Rev. 2
SNC808954
Unit 1 Train A 4.16 kV Breaker Replacement
Rev. 4.0
SNC929182
4kV Switchgear Bus 1K Lightning Arrestor Power
Cable-1VADF02Q
Rev. 2.0
Engineering
Evaluations
Eval 5.29.96
AFW System Check Valve Reversal Flow Operability
Test and Check Valves
May 29,
1996
TEs 1024644, 732042,
808790, 318646
Westinghouse LTR-CRA-
16-102
Steam Generator Tube Rupture Margin to Overfill
Analysis Report
Miscellaneous
CCSI As-Found Inspection Report for Unit 2
Condensate Storage Tank Diaphragm
11/24/2020
A181001
Functional System Description - Service Water System
69.0
A181004
Functional System Description Electrical Distribution
System
Rev. 58
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
A181010
Functional System Description Auxiliary Feedwater
System
FNP-0-M-115
Check Valve Condition Monitoring Plan
IER LI-17-5
Farley's response to IER LI-17-5, Line of Sight to the
Reactor Core
Job Performance
Measure SO-449F
Operation of Steam Generator Atmospheric Relief
Valves for TCOA of EEP-3.0 with a Loss of Instrument
Air
2/08/2018
MIS-17-031
Unit 1 Fifth 10-Year Interval Valve Inservice Testing
Basis Document
MIS-17-032
Unit 2 Fifth 10-Year Interval Valve Inservice Testing
Basis Document
PMCR 97345
Change frequency of CST Inspection to 3 years
7/23/2020
PMCR95348
Preventive Maintenance Change Request for AFW
April 7, 2020
RER 03-032
Evaluation and Testing of K& N Handswitches
2/2/03
SNC1012405
Breaker DG02 Remote Handswitch Replacement
Q2R15HS2007BA
Rev. 2
Qualification Report on CA10 Series Selector Switches
and Aluminum Handles and Retaining Nuts
Rev. 4
Installation, Operation and Maintenance Manual for
Kraus & Naimer Hybrid Contact Selector Switches
Rev.1
U262093
Auxiliary Feedwater Pump Turbine Drive Manual
U612339
Unit 2 - Use of Westinghouse Shield Passive Shutdown
Seal for Flex Strategies
U737296
Farley - Unit No. 1&2 Qualification Report QR 17-02
for Siemens Medium Voltage Vacuum Replacement
Circuit Breakers, 5 KV MSV and Accessories
Rev. 2.0
U737307
Siemens 4160 V Circuit Breaker MSV - Safety-Related
Schematic & Wiring Diagram 18-806-541-411
Rev. 1
Procedures
Licensed Operator Continuing Training Simulator
3.2
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Exercise Guide
FNP-0-ARP-8.0
Annunciator Response Procedure - Service Water
Structure
27.0
FNP-0-MP-10
Reactor Coolant Pump Uncoupling/Recoupling
FNP-0-MP-9.0
RCP Seal Examination and Replacement Incorporating
the Shut Down Seal
FNP-1-AOP-4.0
Loss of Reactor Coolant Flow
FNP-1-AOP-4.1
Abnormal Reactor Coolant Pump Seal Leakage
FNP-1-ARP-1.12
Main Control Board Annunciator Panel M
Rev. 75
FNP-1-ARP-5.0
Unit Startup Transformer Miscellaneous Alarm Panel
Rev 13.1
FNP-1-ECP-3.1
SGTR With Loss of Reactor Coolant, Subcooled
Recovery Desired
25.0
FNP-1-EEP-0
Reactor Trip or Safety Injection
FNP-1-EEP-1
Loss of Reactor or Secondary Coolant
FNP-1-EEP-3
Steam Generator Tube Rupture
FNP-1-EEP-3.0
Steam Generator Tube Rupture
31.0
FNP-1-MP-7.3
Turbine Driven Aux Feed Pump Overspeedtrip Setpoint
Check
FNP-1-SOP-24.0
Service Water System
88.0
FNP-1-STP-22.16
Turbine Driven Auxiliary Feedwater Pump Quarterly
Inservice Test
FNP-1-STP-22.24
Auxiliary Feedwater System Check Valve Reverse
Flow Closure Operability Test
through
FNP-1-STP-22.30
Auxiliary Feedwater Pump Discharge Check Valve
Reverse Flow Closure Operability Test
2, 7 through
FNP-2-AOP-4.0
Loss of Reactor Coolant Flow
FNP-2-AOP-4.1
Abnormal Reactor Coolant Pump Seal Leakage
FNP-2-ECP-0.0
Loss of All AC Power
IP-ENG-001
Standard Design Process
Rev. 1
NMP-OS-014
Time Critical Operator Action Program
2.0
NMP-OS-014-001
FNP Time Critical Operator Action Program
7.0
Work Orders
SNC400246
Performance of FNP-1-STP-22.30
April 20,
2015
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
SNC416549
Inspect the CST tank bladder for degradation
11/14/2020
SNC528671
Unit 1 TDAFWP - Overspeed Trip Test and Coupling
Lube
April 5, 2018
SNC53150, SNC531515,
SNC531516, SNC390897,
SNC390897, SNC390898,
SNC391152, SNC413154,
SNC546630, SNC546630,
SNC546650, SNC546651,
SNC353892, SNC339899,
SNC391154, SNC331162,
SNC573130, SNC391165,
SNC1039631,
SNC1039762,
SNC1041172,
SNC1041310,
SNC1042746,
SNC1042900,
SNC808954, SNC565614,
SNC910159,SNC1012725
SNC975145
FNP-1-STP-22.24
Nov. 4, 2019
SNC981614
Performance of FNP-2-STP-22.24 A Train
Dec. 17,
2019
SNC992621
FNP-1-STP-22.24
Nov. 6, 2019