IR 05000321/2021011
| ML21176A042 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 06/25/2021 |
| From: | James Baptist Division of Reactor Safety II |
| To: | Gayheart C Southern Nuclear Operating Co |
| References | |
| IR 2021011 | |
| Download: ML21176A042 (15) | |
Text
June 25, 2021
SUBJECT:
EDWIN I. HATCH NUCLEAR PLANT UNITS 1 & 2 - DESIGN BASIS ASSURANCE INSPECTION (TEAMS) INSPECTION REPORT 05000321/2021011 AND 05000366/2021011
Dear Ms. Gayheart:
On May 14, 2021, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Edwin I. Hatch Nuclear Plant Units 1 & 2 and discussed the results of this inspection with Johnny Weissinger - Plant Manager 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 Branch 1 Division of Reactor Safety
Docket Nos. 05000321 and 05000366 License Nos. DPR-57 and NPF-5
Enclosure:
As stated
Inspection Report
Docket Numbers:
05000321 and 05000366
License Numbers:
Report Numbers:
05000321/2021011 and 05000366/2021011
Enterprise Identifier: I-2021-011-0010
Licensee:
Southern Nuclear Operating Company, Inc.
Facility:
Edwin I. Hatch Nuclear Plant Units 1 & 2
Location:
Baxley, GA
Inspection Dates:
April 26, 2021 to May 14, 2021
Inspectors:
P. Braxton, Reactor Inspector
P. Carman, Senior Reactor Inspector
K. Mangan, Senior Reactor Inspector
M. Schwieg, Reactor Inspector
R. Smith, Senior Resident Inspector
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 Edwin I.
Hatch Nuclear Plant Units 1 & 2, 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) (5 Samples)
- (1) Time Critical Operator Actions to Reduce Containment Pressure During a Small Break Loss of Coolant Accident (LOCA) and Drywell Pressure is 35 PSIG, within 10 Minutes via one of following methods; Time Critical Operator Action to Start Standby Liquid Control (SBLC) after a LOCA to Buffer Suppression Pool, within Two Hours by one of the following methods:
- Reduce Reactor Pressure Using Main Condenser Bypass Valves to the Main Condenser
- Reduce Reactor Pressure Using Safety Relief Valves (SRVs) to the Torus
- Reduce Drywell Pressure Using Drywell Sprays via the Residual Heat Removal System
- Initiating SBLC Using the Control Switch from the Main Control Room (MCR)
- Initiating SBLC Using Links and Jumpers from the MCR
- Initiating SBLC Using Links and Jumpers and Switch Manipulation Locally
- Component Degradation
- Component Inputs/Outputs
- Consistency among design and licensing bases and other documents/procedures
- System health report, maintenance effectiveness and records, and corrective action history
- Modifications
- Equipment/Environmental Qualification
- Design calculations
- Instrumentation (range, accuracy, and setpoint)
- Surveillance testing and recent test results
- Energy Source (air)
- Time Critical Operator Action to establish MSIV Alternate Path to main condenser within 90 Minutes
- (3) U1 LPCI MCC 1R24-S018B
- Compliance with UFSAR, Technical Specifications (TS), and TS Bases
- Conformance with manufacturer instructions for installation, maintenance, and operation
- Material condition and configuration (i.e. photos provided by licensee)
- System health reports
- Design requirements
- (4) Diesel Generating Building ventilation system
- 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
- Electrical and logic diagrams
- (5) Unit 1 Emergency Diesel Generator 1C
- Design bases documents, system descriptions, and training documents
- Primary design calculations
- System/component health report
- Condition reports associated with component
- Completed surveillance and test procedures
Design Review - Large Early Release Frequency (LERFs) (IP Section 02.02)===
- (1) Unit 1 Reactor Building-to-Suppression Chamber Vacuum Breakers, 1T48-F328A/B
- UFSAR and other applicable design and licensing basis documents
- Design calculations
- Surveillance and in-service testing results
- Consistency between station documentation and vendor specifications
- Corrective maintenance records and corrective action history
- Maintenance effectiveness
- System/component health report
Modification Review - Permanent Mods (IP Section 02.03) (4 Samples)
- (1) EDG Fuel Oil Storage Tank Vent Line Missile Protection, SNC799744
- (2) Degraded Grid - U2 Degraded Voltage Replacement, SNC489866
- (3) SNC338333, Dissolved Gas Monitors - U1 & U2 Kelman Gas Analyzers for Large Power Transformers
- (4) SNC950252, Masterpact Part 21
Review of Operating Experience Issues (IP Section 02.06) (2 Samples)
- (1) NRC Information Notice 2019-03: Inadequate Implementation of Clearance Processes Resulting in Configuration Control Issues.
- (2) IER L3 18-3 - Inadequate Use of Operating Experience and Declining Personnel Experience Lead to Damage to Rod Control Cluster Assembly Extension Shaft While Setting the Reactor Vessel Head.
INSPECTION RESULTS
Very Low Safety Significance Issue Resolution Process: Capability of Diesel Building 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 diesel building ventilation system was not specifically shown to be designed to withstand the effects of a tornado re-pressurization. It is postulated that the differential pressure developed by a specific magnitude tornado could potentially damage the diesel building room ventilation system and challenge the emergency diesel generators (EDGs) to maintain their safety functions due to rapidly increasing room temperatures.
Each EDG and Switchgear room ventilation system consists of two large 100 percent capacity exhaust ventilation fans, associated automatic dampers, and motorized room louver that are arranged to maintain minimum ventilation requirements during diesel operation. The maximum temperature is not expected to exceed 122°F.
When the room ventilation fans are not running, the room louver and auto dampers would be closed. During a tornado re-pressurization event, there would be no venting path to equalize the pressure differential which could damage the room louver and auto dampers
As a result of inspector concerns, the licensee hired a contractor (MPR) to conduct a computer analysis of the louvers and dampers during a tornado event. The evaluation results indicate that the differential pressure caused by the room re-pressurization after the design basis tornado passing will cause the LV-6 louver blades to fail. The LV-6 blades are expected to survive the less severe tornado recommended in Regulatory Guide 1.76. Additionally, the fan dampers are expected to survive the design basis tornado.
Licensing Basis: The NRC staff reviewed the licensing basis documents, regulatory requirements, and regulatory correspondence related to the diesel building tornado protection criterion. The main documents reviewed are detailed below.
- FSAR 3.3.2 TORNADO LOADINGS o All above-ground Seismic Category 1 structures are designed to withstand tornado loadings and horizontal tornado-generated missiles. Components which directly affect the ultimate safe shutdown of the plant are located either under the protection of reinforced concrete or underground. These components include the following o Standby diesel generator system
- FSAR 3.3.2.1 Applicable Design Parameters o For Seismic Category 1 structures designed to withstand tornadoes and horizontal tornado-generated missiles, the following parameters are applied in combinations producing the most critical conditions o Pressure Differential
The structure interior bursting pressure is taken as rising 1 psi/s for 3 s, followed by a 3-s calm, then decreasing at 1 psi/s for 3 s. This cycle accounts for reduced pressure in the eye of a passing tornado. All fully enclosed Category 1 structures are designed to withstand the full 3-psi pressure differential.
- 10 CFR 50, Appendix A, I. Overall Requirements, Criterion 2Design bases for protection against natural phenomena: Structures, systems, and components important to safety shall be designed to withstand the effects of natural phenomena such as earthquakes, tornadoes, hurricanes, floods, tsunami, and seiches without loss of capability to perform their safety functions. The design bases for these structures, systems, and components shall reflect:
- (1) Appropriate consideration of the most severe of the natural phenomena that have been historically reported for the site and surrounding area, with sufficient margin for the limited accuracy, quantity, and period of time in which the historical data have been accumulated,
- (2) appropriate combinations of the effects of normal and accident conditions with the effects of the natural phenomena and
- (3) the importance of the safety functions to be performed.
- 10 CFR 50, Appendix B, Criterion III, Design Control: Measures shall be established to assure that applicable regulatory requirements and the design basis, as defined in 10 CFR 50.2 and as specified in the license application, for those structures, systems, and components to which this appendix applies are correctly translated into specifications, drawings, procedures, and instructions.
- Regulatory Issue Summary (RIS) 2006-23: Notifies licensees of its regulatory position regarding loading effects caused by natural phenomena to safety related systems and components housed inside a structure partially exposed to the outside environment, specifically ventilating and air-conditioning (VAC) systems housed in the EDG room.
- Regulatory Guide 1.76 (issued in March 2007): Provides licensees and applicants with new guidance that the NRC staff considers acceptable for use in selecting the design-basis tornado and design-basis tornado-generated missiles that a nuclear power plant should be designed to withstand to prevent undue risk to the health and safety of the public.
The licensee provided information on why they believed the issue of concern is not in their licensing basis. The licensees review concluded that tornado depressurization structural design criteria applies to the design of Category 1 structures only. There is no commitment or requirement in the UFSAR extending this structural design criteria to individual systems or components, or in this case to the DG building fans or related components.
The inspectors did not agree with the licensees design basis determination. The Diesel Generating room louvers and auto dampers are exposed to the outside pressure and will experience high differential pressure during a tornado. These components should be considered as part of the EDG building structural design and be designed to withstand the differential pressure caused by a design basis tornado.
Following the inspectors issue of concern, the licensee revised the site procedure 34AB-Y22-002-0 Naturally Occurring Phenomena to add an operator action during a tornado warning to start one Diesel and Switchgear room fan and to ensure room has its louver open. The licensee provided a hand calculation, with the room louver open, to show the maximum room pressure differential will be below the damper and louver design rating (0.28 psid). In other words, with the room fan running, the dampers and louvers would be protected by the design basis tornado.
Based on the low probability of an event of this magnitude and the licensees actions taken, the inspectors concluded that 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 8.2.3 and NRC Hatch SPAR model Version 8.58. The conditional analysis assumed failure of the EDG ventilation louvers 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 reactor core isolation cooling (RCIC) 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-06/year and an estimated increase in large early release frequency of <1E-07/year, representing very low safety significance (Green).
Technical Assistance Request: A technical assistance request (TAR) was not initiated.
Corrective Action Reference: CR
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On May 14, 2021, the inspectors presented the design basis assurance inspection (teams) inspection results to Johnny Weissinger - Plant Manager and other members of the licensee staff.
- On June 23, 2021, the inspectors presented the Phone Re-Exit for the Hatch DBAI Meeting inspection results to Brian Waltman and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
71111.21M Calculations
Vacuum Breaker Sizing for 67 Product Line, Torus/Lightbulb
Containments
2/1970
S18643
Discontinuity Calculations F/20X20 Vacuum Breaker
11/19/1971
S18646
Seismic Calculation for 20 X 20 Vacuum Breaker Vlv
Rev. A
SCNH-13-021
Evaluation Of Plant Hatch Local Intense Precipitation Severe
Accident Management (Sam) For Fukushima Near-Term
Task Force (NTTF) Recommendation 2.1 Flooding Re-
Evaluation
Rev. 1.0
SENH-89-009
Steady State Loading Emergency Buses 1E, 1F & 1G
During a LOCA/LOSP/SBO Event
Rev. 17
SENH-94-013
Coordination Study for Non-Appendix R Breakers and
Fuses in Response to REA HT-93753
Rev.7
SMNH-15-006
EDG Bay and Battery Rooms Exhaust Area Required to
Prevent Pressure Differential During Design Basis Tornado
Rev. 1
Corrective Action
Documents
10116247
209664,
212821,
213119,
232344,
10464440,
10527495
10467098
2/28/2018
10467100
2/28/2018
2/01/2016
CR10753014
11/11/2020
Corrective Action
Documents
Resulting from
Inspection
10793548
04/27/2021
10793550
04/27/2021
10793879
04/28/2021
10794181
04/29/2021
10794215
04/29/2021
10795264
U1 FSAR Code of Record
5/4/2021
10797616
21 Hatch DBAI - Vacuum Breaker Sizing Design
05/13/2021
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Calculation
Drawings
B-44875
Diesel Generator Building North Access Door Modifications
Rev. 0
H-12615
Diesel Generating Building Roof and Floor Plan
Rev. 7
H-13395
Diesel Generator Heating and Ventilation
Rev. 20
H-16024
Primary Containment Purge & Inerting System P.&I.D.
Ver. 54.0
H-16062, SHT 1
Nuclear Boiler System P&ID
Rev. 57
H-17012
Reactor Building 600V MCC "1E-A" & " 1E-B' MPL R24-
S018A & R24-S018B
Rev. 30
S18136
B/M 20 X 20 VAC. BKR.
Rev. E
S71062
Bill of Material 20 Pallet Assembly
03/02/1990
SX-17731
Assembly Drawing 20 Vacuum Breakers 20 ST/20 Flange
Rev. J
Engineering
Changes
SNC338333
Kelman Gas Analyzers for Transformers
Rev. 3
Engineering
Evaluations
LR-REG-003-
0404
Response to OE 14370 (Testing Methodology For MSIVs
May Not Support USAR and Licensing Commitments)
04/13/2004
NMP-ES-050-F01 RER Response Form for SNC 510820 - Sequence 1
08/02/2013
NMP-ES-050-F01 RER Response Form for SNC510820 - Sequence 2
08/26/2014
NMP-GM-003-
F19
Focused Area Self-Assessment (FASA) Plan and Report
Rev. 3
SNC950252
Masterpack Part 21
Rev. 1
TE1047898
09/08/2019
TE1055365
09/18/2020
Miscellaneous
EDG Room Main Louvers and associated thermostat
Rev. 0
Hatch Position on Effects of Tornado Induced
depressurization on Emergency Diesel Generator Building
Ventilation System Components
05/13/2021
Ltr From Bechtel Power Corporation to
- E.I Hatch, IEN 85-48
June 30,
1986
Volumetric Leak Rate Monitor Local Leak Rate Test Data
Sheet, MPL Number: 1T48-F310 & F328A
2/22/2018
Volumetric Leak Rate Monitor Local Leak Rate Test Data
Sheet, MPL Number: 1T48-F310 & F328A Retest
03/01/2020
Volumetric Leak Rate Monitor Local Leak Rate Test Data
2/11/2018
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Sheet, MPL Number: 1T48-F311 & F328B
Volumetric Leak Rate Monitor Local Leak Rate Test Data
Sheet, MPL Number: 1T48-F311 & F328B
2/03/2020
Surveillance Frequency Control Program, Surveillance Test
Interval List
Rev. 22
Georgia Power Interoffice Correspondence from G.A. Goode
to
January 13,
1987
1R24 System
Health Report
June 2019, June 2020, June 2021
H-LT-PP-X86-
FLEX-LOCT-
20303
Plant Hatch FLEX Strategies (X86)
Rev. 2.0
Inadequate Inservice Testing of Main Steam Isolation Valves
LDCR 2021-005
Vacuum Breaker Inspection
Ver. 1.0
NMP-OS-014-
2, Attachment
1, 2 and 3
HNP Time Critical Operator Action Program - Training for
05/12/2021
S70572
Vendor Manual-Instruction Valueline Mark 1 MCC's
Installation, Operations, and Maintenance
MSIV Closure Testing Requirement
2/22/89
SNC338333
Design Input Record
Rev. 1
SS6914-19
Specification for Louvers for Diesel Generating Building U1
and U2
09/18/1972
SX-17731
Assembly Drawing 20 Vacuum Breakers 20 ST/20 Flange
Rev. J
Procedures
31-GO-OPS-006-
Condition, Required Actions, and Completion Times
Rev. 8.7
1/2
RC RPV Control (Non-ATWS)
Rev.
2.0/12.0
1/2
PC Primary Containment Control
Rev. 7.1/7.1
1/2
CP-1 ALTERNATE LEVEL CONTROL, STEAM COOLING,
& EMERGENCY RPV DEPRESSURIZATION
Rev.
10.1/11.1
Miscellaneous Emergency Overrides
Rev. 5.2/8.4
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
1/2
1/2
ALTERNATE RPV PRESSURE CONTROL
Rev. 5.6/5.5
1/2
SEVERE ACCIDENT GUIDELINE 2
Rev. 7.0/7.0
1/2
MAIN STEAM LINE HIGH RADIATION OR SUSPECTED
FUEL ELEMENT FAILURE
Rev.
5.1/4.15
Naturally Occurring Phenomena
Rev. 20
34GO-OPS-056-0 Receipt of Diesel Generator, Security Diesel, Dry Storage
(ISFSI) Diesel, Diesel Fire Pumps, and Auxiliary Boiler Fuel
Oil
Rev. 12
34GO-SUV-001-0 Control And Surveillance Of Locked Valves,
Lock Wired Valves, And Locked Breakers
Rev. 28.6
1/2
STANDBY LIQUID CONTROL SYSTEM
Rev.
2.7/12.6
1/2
Residual Heat Removal System
Rev.
45.3/44.5
34SV-SUV-01901 Surveillance Procedure
Ver. 37.38
Reactor Building to Suppression Chamber Vacuum Relief
System Operability
Ver. 8.1
Containment Leakage Rate Testing Plan
Ver. 9.0
1/2
Reactor Vessel Reassembly
Rev. 26.7/21
1/2
Reactor Vessel Disassembly
Rev.
2.9/18.9
Torus to Reactor Building Vacuum Breaker Major
Inspection/Overhaul
Rev. 5.3
Torus to Reactor Building Vacuum Breaker Inspection
Rev. 2.0
HNP-AP-001-F08
Site Procedure Approval Form
09/28/2016
HNP-OS-014-002
HNP Time Critical Operator Action Program
Rev. 2.0
NMP-AD-003
Equipment Clearance and Tagging
Rev. 26.0
NMP-GM-005-
2
Human Performance Tools Instruction
Rev. 9.1
NMP-GM-005-
Communication Plan for Crew Learning - From NRC Design
04/29/2021
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
005-F02
Basis Assessment Inspection
NMP-GM-008-
F02
Typical Operating Experience Evaluation Format
Rev. 6.2
NMP-OS-007
Conduct of Operations
Rev. 17.0
NMP-OS-007-001 Conduct of Operations Standards and Expectations
Rev. 17.1
NMP-OS-007-005 Site Specific Operations Expectations and Fleet Operations
Policies
Rev. 2.0
NMP-OS-014
Time Critical Operator Action Program
Rev. 3.0
NMP-OS-014-002 HNP Time Critical Operator Action Program
Rev. 4.0
NMP-OS-014-
2-F01
Exclusion of Actions from MCTCA/MLTSA
06/24/2014
NMP-OS-014-
2-F02
Operator Response Time Validation - for Placing MSIV ALT
Path in Service Within 90 Minutes
08/19/2021
NMP-OS-014-
2-F02
Operator Response Time Validation - Take Action Within 10
Minutes of Drywell Pressure Reaching 35 PSIG
08/19/2020
NMP-OS-014-
2-F02
Operator Response Time Validation - Start SBLC Within 2
Hours
08/17/2020
NMP-OS-017
Severe Weather
Rev. 3
Self-Assessments SNC 950252
CFR 50.59 Screening
Rev. 1
Work Orders
SNC 553933,
SNC 553942,
SNC 925687,
25857, SNC
25858, SNC
1071304, SNC
359906, SNC
400164, SNC
400165, SNC
585222
SNC571213,
SNC571613,
SNC785958,
SNC786383,
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
SNC964804,
SNC965758,
SNC966852
SNC587388
Replace Fan Motor
SNC785593
SNC786889
SNC799744