IR 05000327/2022001
ML22130A795 | |
Person / Time | |
---|---|
Site: | Sequoyah |
Issue date: | 05/11/2022 |
From: | Renee Taylor Division Reactor Projects II |
To: | Bartow J Tennessee Valley Authority |
References | |
IR 20220001 | |
Download: ML22130A795 (22) | |
Text
SUBJECT:
SEQUOYAH, UNITS 1 AND 2 - INTEGRATED INSPECTION REPORT 05000327/2022001, 05000328/2022001 AND 07200034/20220001
Dear Mr. Barstow:
On March 31, 2022, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Sequoyah, Units 1 and 2. On April 26, 2022, the NRC inspectors discussed the results of this inspection with Mr. Tom Marshall and other members of your staff. The results of this inspection are documented in the enclosed report.
Two findings of very low safety significance (Green) are documented in this report. One of these findings involved a violation of NRC requirements. We are treating this violation as a non-cited violation (NCV) consistent with Section 2.3.2 of the Enforcement Policy.
A licensee-identified violation which was determined to be of very low safety significance is documented in this report. We are treating this violation as a non-cited violation (NCV)
consistent with Section 2.3.2 of the Enforcement Policy.
If you contest the violations or the significance or severity of the violations documented in this inspection report, you should provide a response within 30 days of the date of this inspection report, with the basis for your denial, to the U.S. Nuclear Regulatory Commission, ATTN:
Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, Region II; the Director, Office of Enforcement; and the NRC Resident Inspector at Sequoyah, Units 1 and 2.
If you disagree with a cross-cutting aspect assignment or a finding not associated with a regulatory requirement in this report, you should provide a response within 30 days of the date of this inspection report, with the basis for your disagreement, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, Region II; and the NRC Resident Inspector at Sequoyah, Units 1 and 2.
May 11, 2022 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, Thomas A. Stephen, Chief Projects Branch 5 Division of Reactor Projects Docket Nos. 05000327, 05000328 and 07200034 License Nos. DPR-77 and DPR-79
Enclosure:
As stated
Inspection Report
Docket Numbers:
05000327, 05000328, and 07200034
License Numbers:
Report Numbers:
05000327/2022001, 05000328/2022001, AND 07200034/20220001
Enterprise Identifier:
I-2022-001-0025
I-2022-001-0036
Licensee:
Tennessee Valley Authority
Facility:
Sequoyah, Units 1 and 2
Location:
Soddy Daisy, TN 37379
Inspection Dates:
January 01-March 31, 2022
Inspectors:
D. Hardage, Senior Resident Inspector
P. Cooper, Senior Reactor Inspector
N. Childs, Resident Inspector
Approved By:
Thomas A. Stephen, Chief
Projects Branch 5
Division of Reactor Projects
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Sequoyah, Units 1 and 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. A licensee-identified non-cited violation is documented in report section: 71114.0
List of Findings and Violations
Inadequate Design Control for ISFSI Operations Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV05000327,05000328/2022001-01 Open None (NPP)60855 The team identified three examples of a Green, non-cited violation of Title 10, Code of Federal Regulations Part 50, Appendix B, Criterion III, Design Control, for the licensees failure to assure that the design basis was correctly translated into procedures and instructions.
Specifically, the inspectors identified that the licensee failed to develop appropriate acceptance criteria associated with the ISFSI haul path and the railway access hatch hoisting system and failed to verify the adequacy of the Auxiliary Building Crane testing program.
Failure to Install the Correct Orifice Block on Unit 2 Main Turbine Throttle Valve (TV-1) as Required by Maintenance Work Instructions Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green FIN 05000328/2022001-02 Open
[H.2] - Field Presence 71111.15 A self-revealed Green finding was identified when the licensee failed to ensure the correct orifice block was installed on Unit 2 main turbine TV-1, resulting in the valves inability to reliably isolate on a turbine trip signal. Specifically, the licensee failed to ensure the correct orifice block was installed during planned valve replacement activities as required by quality critical maintenance (QCM) step 5.7 of preventive maintenance work instruction PM21626.
Additional Tracking Items
Type Issue Number Title Report Section Status AV 05000327,05000328/20 21003-02 Failure to Ensure Accurate Instrumentation Threshold Values Are Used for Certain Emergency Classifications 71114.04 Closed LER 05000328/2021002-00 LER 2021-002-00 for Sequoyah Nuclear Plant,
Unit 2, Turbine Trip Function Inoperable Due to Slow to Close Turbine Throttle Valve 71153 Closed
Plant Status Unit 1 and Unit 2 operated at or near rated thermal power for the entire inspection period.
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 performed activities described in IMC 2515, Appendix D, Plant Status, conducted routine reviews using IP 71152, Problem Identification and Resolution, observed risk significant activities, and completed on-site portions of IPs. 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
71111.01 - Adverse Weather Protection
Impending Severe Weather Sample (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated the adequacy of the overall preparations to protect risk-significant systems from impending severe weather for extreme cold conditions on January 7, 2022.
71111.04 - Equipment Alignment
Partial Walkdown Sample (IP Section 03.01) (2 Samples)
The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:
- (1) Vital Instrument Board 1-II with invertor 1-II out of service for functional testing on January 26, 2022 (2)2B Emergency Diesel Generator (EDG) while 2A EDG was out of service for battery charger replacement on March 1, 2022
Complete Walkdown Sample (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated system configurations during a complete walkdown of the Essential Raw Cooling Water (ERCW) system on March 29, 2022.
71111.05 - Fire Protection
Fire Area Walkdown and Inspection Sample (IP Section 03.01) (5 Samples)
The inspectors evaluated the implementation of the fire protection program by conducting a walkdown and performing a review to verify program compliance, equipment functionality, material condition, and operational readiness of the following fire areas:
- (1) Unit 1 and Unit 2 Auxiliary Building, Elevation 669, on January 18, 2022
- (2) EDG Building, Elevation 740.5, on January 21, 2022
- (3) EDG Building Elevation 722, on March 2, 2022
- (4) Unit 1 and Unit 2 Cable Spreading Room, Control Building Elevation 706, on March 3, 2022
- (5) ERCW Building on March 22, 2022 Fire Brigade Drill Performance Sample (IP Section 03.02) (1 Partial)
(1)
(Partial)
The inspectors evaluated fire brigade performance on January 12, 2022.
71111.07A - Heat Exchanger/Sink Performance
Annual Review (IP Section 03.01) (1 Sample)
The inspectors evaluated readiness and performance of:
(1)1A1 component cooling system heat exchanger and observed state of cleanliness on February 14, 2022
71111.11Q - Licensed Operator Requalification Program and Licensed Operator Performance
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
- (1) The inspectors observed and evaluated a simulator examination scenario on March 10, 2022
71111.12 - Maintenance Effectiveness
Maintenance Effectiveness (IP Section 03.01) (2 Samples)
The inspectors evaluated the effectiveness of maintenance to ensure the following structures, systems, and components (SSCs) remain capable of performing their intended function:
(1)bearing failure and seizure of the 1B MDAFW pump shaft on May 27, 2021 (2)maintenance rule functional failure of Unit 2 hydrogen mitigation system (CDE 3161)on October 25, 2021
71111.13 - Maintenance Risk Assessments and Emergent Work Control
Risk Assessment and Management Sample (IP Section 03.01) (5 Samples)
The inspectors evaluated the accuracy and completeness of risk assessments for the following planned and emergent work activities to ensure configuration changes and appropriate work controls were addressed:
- (1) Unit 1 and 2, week of January 9-January 15, 2022, including protection equipment reviews for scheduled maintenance on the 1B EDG, R-A ERCW pump, and ERCW pump well B-B inspection
- (2) Unit 1 and 2, week of January 23-January 29, 2022, including protection equipment reviews for scheduled maintenance on the 1-II Vital Invertor, R-A ERCW pump, and M-B ERCW pump
- (3) Unit 1 and 2, week of February 13-February 19, 2022, including protection equipment reviews for scheduled maintenance on the 1A1 component cooling water heat exchanger, R-A ERCW pump, and 2A charging pump
- (4) Unit 1 and 2, week of February 27-March 5, 2022, including protection equipment reviews for scheduled maintenance on the 1A2 component cooling water heat exchanger, 2A EDG, A Auxiliary Air Compressor, and emergent failure of Unit 2 power range NI channel N-41.
- (5) Unit 1 and 2, week of March 6-March 12, 2022, including protection equipment reviews for scheduled maintenance on the B Auxiliary Air Compressor, 2B EDG and R-A ERCW pump
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (5 Samples)
The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:
(1)damage identified on B main control room (MCR) chiller oil piping, cable and flex conduit on December 6, 2021 (2)leak discovered in ceiling above 0-M-29 in the MCR on January 7, 2022 (3)lock washer not installed on Unit 2 steam driven auxiliary feedwater (AFW) pump trip linkage on March 18, 2022 (4)perform POE on ERCW leak off the return header upstream of 2-VLV-67-0549B on October 29, 2021
- (5) Unit 2 main turbine throttle valve TV-1 slow to close during turbine overspeed trip testing on November 8, 2021
71111.18 - Plant Modifications
Temporary Modifications and/or Permanent Modifications (IP Section 03.01 and/or 03.02) (1 Sample)
The inspectors evaluated the following temporary or permanent modifications:
71111.19 - Post-Maintenance Testing
Post-Maintenance Test Sample (IP Section 03.01) (6 Samples)
The inspectors evaluated the following post-maintenance testing activities to verify system operability and/or functionality:
- (2) Work Order (WO) 1219400448, testing of 1B AFW pump and breaker following replacement of HFA relays 1X, 30X and 30RX, on February 7, 2022
- (3) WO 121940472, 1-MOVP-063-153-B EQ inspection, following replacement of damaged cabling, on February 8, 2022
- (4) WO 121927263, Perform a clam and mic inspection on 1A1 CCS Heat Exchanger, on February 17, 2022
- (5) WO 120673932, Replace existing fire/flood mode pump motor A-A, and re-work splice, on March 4, 2022
- (6) WO 122790938, Repair or Replace Unit 2 N41 control power filter identified during troubleshooting as faulty, on March 18, 2022
71111.22 - Surveillance Testing
The inspectors evaluated the following surveillance testing activities to verify system operability and/or functionality:
Surveillance Tests (other) (IP Section 03.01) (2 Samples)
(1)1-SI-SXP-063-201.A, Safety Injection Pump 1A-A Performance Test, on February 2, 2022
- (2) 1-SI-OPS-082-024.A, 1A-A D/G 24 Hour Run and Load Rejection Test, on February 16, 2022
Inservice Testing (IP Section 03.01) (1 Sample)
(1)0-SI-SXP-067-201.R, Essential Raw Cooling Water Pump R-A Performance Test, on March 14, 2022
71114.04 - Emergency Action Level and Emergency Plan Changes
Inspection Review (IP Section 02.01-02.03)
(Closed) Apparent Violation: Failure to Ensure Accurate Instrumentation Threshold Values Are Used for Certain Emergency Classifications; AV 05000327,05000328/2021003-02 During the Significance and Enforcement Review Panel (SERP) review, the apparent violation documented in inspection report 2021-003 (ML21314A097), was determined to be a licensee identified non-cited violation of very low safety significance (Green). This is because numerous low probability conditions would need to occur to enable a CG1 or CS1 classification: plant operations would have been aware of a challenge to maintain RVLIS level before the 64% threshold, and would have taken steps to close containment, increase RCS level, or both; assuming containment closure was challenged, the plant operators would still have 30 minutes to increase the level above 64%; the 4% difference in RVLIS would not have significantly increased public risk with early evacuation, in that it wouldnt have significantly shortened the amount of time to classify the Initiating Condition.
Prior to initiating the AV the licensee had documented the discrepancy in Condition Report (CR) 1673364. The EAL was corrected on March 5, 2021. In addition, the process to initiate a causal evaluation was documented in CR 1676064.
The inspectors determined the AV to be a non-cited LIV, because it is very low safety significance, corrective actions were taken to restore full compliance, and planned actions have been taken to address recurrence via a causal evaluation.
71114.06 - Drill Evaluation
Select Emergency Preparedness Drills and/or Training for Observation (IP Section 03.01) (1 Sample)
(1)emergency preparedness drill conducted February 9,
OTHER ACTIVITIES - BASELINE
===71151 - Performance Indicator Verification The inspectors verified licensee performance indicators submittals listed below:
BI01: Reactor Coolant System (RCS) Specific Activity Sample (IP Section 02.10)===
- (1) Unit 1 (January 2021-December 2021)
- (2) Unit 2 (January 2021-December 2021)
BI02: RCS Leak Rate Sample (IP Section 02.11) (2 Samples)
- (1) Unit 1 (January 2021-December 2021)
- (2) Unit 2 (January 2021-December 2021)
71152A - Annual Follow-up Problem Identification and Resolution Annual Follow-up of Selected Issues (Section 03.03)
The inspectors reviewed the licensees implementation of its corrective action program related to the following issues:
- (1) CR 1734304, Magnetite Identified in multiple steam generator sense lines during U2R24
71153 - Follow Up of Events and Notices of Enforcement Discretion Event Report (IP Section 03.02)
The inspectors evaluated the following licensee event reports (LERs):
- (1) LER 05000328/2021-002-00, Turbine Trip Function Inoperable Due to Slow to Close Throttle Valve (ADAMS accession: ML22006A232). The inspection conclusions associated with this LER are documented in this report under the Inspection Results.
OTHER ACTIVITIES
- TEMPORARY INSTRUCTIONS, INFREQUENT AND ABNORMAL
===60855 - Operation of An ISFSI 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) 2690, Inspection Program for Storage of Spent Reactor Fuel and Reactor-Related Greater-than-Class C Waste at Independent Spent Fuel Storage Installations (ISFSI) and for 10 CFR Part 71 Transportation Packagings."
Operation Of An ISFSI===
- (1) Operation of an Independent Spent Fuel Storage Installation From January 17-24, 2022, the inspectors performed a review of the licensees ISFSI activities to verify compliance with regulatory requirements. During the on-site inspection, the inspectors observed and reviewed licensee activities in each of the five safety focus areas including occupational exposure, public exposure, fuel damage, confinement, and impact to plant operations.
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. Additionally, the inspectors performed independent walkdowns of the heavy load lifting equipment and the ISFSI haul path. The inspector also performed an independent radiation survey of the ISFSI pad. The inspection conclusions are documented in this report under the Inspection Results.
INSPECTION RESULTS
Inadequate Design Control for ISFSI Operations Cornerstone Significance Cross-Cutting Aspect Report Section Barrier Integrity Green NCV 05000327,05000328/2022001-01 Open None (NPP)60855 The team identified three examples of a Green, non-cited violation of Title 10, Code of Federal Regulations Part 50, Appendix B, Criterion III, Design Control, for the licensees failure to assure that the design basis was correctly translated into procedures and instructions. Specifically, the inspectors identified that the licensee failed to develop appropriate acceptance criteria associated with the ISFSI haul path and the railway access hatch hoisting system and failed to verify the adequacy of the Auxiliary Building Crane testing program.
Description:
During the week of January 17, 2022, the inspectors observed activities and reviewed documentation associated with the Independent Spent Fuel Storage Installation (ISFSI) campaign. The inspectors identified three examples where the design basis criteria were not translated into procedures and instructions.
For the first example, during a walkdown of the ISFSI haul path, the inspectors identified that the roller compacted concrete surface showed evidence of deterioration in the form of erosion, spalling, and cracking. The function of the haul path is to provide protection to underground safety related components by distributing the additional load of the ISFSI crawler and to provide a physical barrier from the potential impacts of external phenomena such as tornado missiles. In response to the identified condition the inspectors interviewed licensee staff and learned that the deterioration of the surface was expected and permissible by original construction specifications. The inspector, however, reviewed the calculation that evaluates impact to underground commodities, SCG1S620, Assessment of Utilities Beneath Dry Cask Transportation Haul Roadway, and determined that the calculation did not incorporate the degradation of the surface but rather assessed the impacts based on the original thickness of 18-inches. Upon further review, the inspector identified that the design basis criteria were not incorporated into procedures or instructions to ensure the analyzed 18-inch cross section was maintained. In response to the identified concern about the current surface thickness, as well as future progressive degradation, the licensee performed a preliminary assessment and determined that the current condition of the haul path did not adversely impact underground commodities and continued to perform its intended function.
For the second example, during the observation of ISFSI stack-up activities, the inspector noted that the railways access hatch covers were leaning towards the ISFSI cask while being supported by a hoisting system that was not qualified to be single-failure-proof. UFASR Section 3.8.4.1.1, Auxiliary Control Building, states that all spent fuel casks, new fuel shipments, and major items of equipment entering or leaving the Auxiliary Building above the Elevation 734.0 floor must go through this hatchway. This includes both quality and safety related components such as the pressurizer safeties, power operated relief valves, reactor coolant pump motor and reactor coolant pump. The inspectors interviewed licensee staff and determined that the failure of the railways access hatch hoisting system resulting in a drop of the railway access door hatch had not been evaluated to prevent damage to the spent fuel cask or safety related equipment. Further conversations revealed that the design basis relied upon the full retraction of the railways access hatch covers until the covers were leaning against the bumpers. The fully retracted state ensures that that the failure of the hoisting system would result in the hatch door dropping towards the exterior wall and would not result in a drop towards the ISFSI casks during stack-up activities or result in damage to safety related equipment while being handled through the railway access hatch opening. In response to the inspectors questioning, the licensee reviewed procedures GOI-6 and FPMI-12.2, which describe the methodology to open the railways access hatch covers and determined that the requirement to confirm that the hatches were in the fully retracted position was not translated into those procedures or instructions. The licensee initiated actions to immediately correct the condition.
For the third example, UFSAR Section 3.8.6.2, Auxiliary Building Crane, states that the main hoist must meet NUREG-0554, Single-Failure-Proof Cranes for Nuclear Power Plants, single failure proof criteria for compliance with 10 CFR 72.124(a), Design for Criticality Safety, for handling spent fuel casks. NUREG-0554, Single-Failure-Proof Cranes for Nuclear Power Plants, Section 9, Operating Manual, states that the crane designer and crane manufacturer should provide a manual of information and procedures to use in checking, testing, and operating the crane. Additionally, UFSAR Section 3.8.6.2 states that the Ederer Topical Report, was utilized to ensure that the crane met the requirements to be qualified as single-failure-proof. Ederer (the crane manufacturer) developed the Ederer Topical Report which describes the design and testing of the single-failure-proof features that are added to or working in connection with the standard hoisting equipment which is intended for handling of spent fuel casks and other loads that are considered critical to preserving the safety of the plant operation. The inspectors reviewed the Ederer Topical Report and compared it to the licensees crane maintenance procedure 0-MI-ECR-303-921.0, Auxiliary Building Crane Periodic Inspection, and identified that several inspections and tests described in the Ederer Topical Report where not incorporated into the procedure as described. The inspectors interviewed licensee staff and determined that an evaluation for the missing tests or an evaluation of the alternative methods for testing were not performed to ensure that the equivalent level of safety with the maintenance and testing program prescribed by the crane manufacturer was utilized to maintain the single-failure-proof qualification of the Auxiliary Building Crane. The licensee initiated corrective actions to correct the nonconformance's of testing requirements.
Corrective Actions: 1748950, 1750618, and 1750635
Performance Assessment:
Performance Deficiency: The team determined that the failure to develop appropriate acceptance criteria associated with the ISFSI haul path and the railway access hatch hoisting system and failed to verify the adequacy of the Auxiliary Building Crane testing program. was a performance deficiency.
Screening: The inspectors determined the performance deficiency was more than minor because, if left uncorrected, it would have the potential to lead to a more significant safety concern.
For the first example, the failure to develop and translate acceptance criteria for the degradation of the roller compacted concrete ISFSI haul path into procedures resulted in reasonable doubt that that ISFSI operations would not adversely impact the functionality of plant underground safe shutdown equipment and that the thickness of the haul path would continue to provide an adequate level of protection from external phenomena.
For the second example, the failure to develop and translate acceptance criteria for the railway access hatch hoisting system, introduced the potential for a heavy load drop of the access hatch should the hoisting system fail. The drop of the access hatch has the potential to damage quality related and safety related plant equipment during material handling activities. Additionally, the heavy load drop during ISFSI stack-up operations introduced potential impacts on the stability of stack-up activities that had not been previously analyzed.
For the third example, the failure to verify the adequacy of the Auxiliary Building Crane testing program to assure the equivalent level of safety with the maintenance and testing program prescribed by the vendor has the potential to decrease the load handling reliability of the crane and increase the likelihood of a load drop of the spent fuel cask and subsequently damage spent fuel, the spent fuel pool and associated components due to a crane malfunction.
Significance: The inspectors assessed the significance of the finding using Appendix A, The Significance Determination Process (SDP) for Findings At-Power. The finding screened as Green because the inspectors answered No to all six questions described in this appendix.
The inspectors identified that two cornerstones were impacted, Mitigating Systems and Barrier Integrity, and screened each one independently for significance. In regard to the Mitigating Systems cornerstone, using IMC 0609, Exhibit 2 - Mitigating Systems Screening Questions, the finding was determined to be of very low safety significance (Green) because it
- (1) was not a design deficiency,
- (2) did not represent a loss of system and/or function, (3)did not represent an actual loss of function of at least a single train for longer than its technical specification allowed outage time,
- (4) did not represent a loss of the probability risk analysis function of two separate technical specification systems for greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />,
- (5) did not represent a loss of probability risk analysis system and/or function for greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, and
- (6) did not result in the loss of a high safety-significant, nontechnical specification train. In regard to the Barrier Integrity Cornerstone, using IMC 0609, Exhibit 4 - Barrier Integrity Screening Questions, Section E, Spent Fuel Pool (SFP), the finding was determined to be of very low safety significance (Green) because it:
- (1) did not adversely affect decay heat removal capabilities from the spent fuel pool,
- (2) did not result from fuel handling errors, dropped fuel assembly, dropped storage cask, or crane operations over the spent fuel pool,
- (3) did not result in a loss of spent fuel pool water inventory, and
- (4) did not affect the SFP neutron absorber, fuel bundle misplacement, or soluble boron concentration.
Although both cornerstones resulted in a determination of very low safety significance (Green), the inspector qualitatively determined that the impact to the Barrier Integrity Cornerstone was the most significant.
Cross-Cutting Aspect: Not Present Performance. No cross-cutting aspect was assigned to this finding because the inspectors determined the finding did not reflect present licensee performance.
Enforcement:
Violation: 10 CFR Part 50, Appendix B, Criterion III, Design Control, requires the design control measures shall provide for verifying or checking the adequacy of design, such as by the performance of design reviews, by the use of alternate or simplified calculational methods, or by the performance of a suitable testing program.
Contrary to the above, since the original ISFSI loading campaign in 2005, the inspector identified three examples where the licensee failed to assure that applicable regulatory requirements and the design basis were correctly translated into procedures, and instructions. Specifically, the inspectors identified that the licensee failed to develop appropriate acceptance criteria associated with the ISFSI haul path and the railway access hatch hoisting system and failed to verify the adequacy of the Auxiliary Building Crane testing program.
Enforcement Action: This violation is being treated as an NCV, consistent with Section 2.3.2 of the Enforcement Policy.
Failure to Install the Correct Orifice Block on Unit 2 Main Turbine Throttle Valve (TV-1) as Required by Maintenance Work Instructions Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green FIN 05000328/2022001-02 Open/Closed
[H.2] - Field Presence 71111.15 A self-revealed Green finding was identified when the licensee failed to ensure the correct orifice block was installed on Unit 2 main turbine TV-1, resulting in the valves inability to reliably isolate on a turbine trip signal. Specifically, the licensee failed to ensure the correct orifice block was installed during planned valve replacement activities as required by quality critical maintenance (QCM) step 5.7 of preventive maintenance work instruction PM21626.
Description:
During the 2021 Unit 2 refueling outage, several turbine control system valves, including TV-1, were replaced in accordance with preventive maintenance requirements.
Refurbished valves received from the vendor typically arrived with flushing blocks installed and were clearly marked as such. Two of the replacement valves received from the vendor were clearly marked as having flushing blocks installed. The replacement for TV-1 was received with an unmarked flushing block installed. QCM step 5.7 of PM21626 ensures the correct orifice block is installed and required supervisory oversight is present in the field to witness the installation. This step was not completed as required and TV-1 valve replacement proceeded on October 28, 2021, with the unmarked flushing block installed.
On November 8, 2021, during performance of periodic instruction 2-PI-OPS-047-760.1, Unit 2 Main Turbine Overspeed Trip Tests, main turbine TV-1, was noted to close in 10 seconds versus its response time acceptance criteria of less than 1.1 seconds. Troubleshooting activities discovered that a flushing block was installed on TV-1 instead of the correct orifice block. The specified function of the main turbine TVs is to close on a turbine trip signal and stop steam flow to the turbine to prevent turbine damage (Limiting conditions for operation (LCO) 3.3.2 function 5.b). Technical Specification (TS) 3.3.2, Engineered Safety Feature Actuation System (ESFAS) Instrumentation, requires that the main turbine TVs close in less than 1.1 seconds (Surveillance Requirement 3.3.2.9) so that, when combined with other trip logic in a turbine trip signal, the overall response time testing requirement of 2.5 seconds for a turbine trip is met (Final Safety Analysis Report (FSAR)
Table 7.3.1-4 Table 8). The turbine trip function is required to be operable in Modes 1 through 3 and requires four out of four main turbine TVs to close. With the flushing block installed, the operation of TV-1 became unpredictable and there wasnt reasonable assurance that the valve would operate as required.
The licensee concluded that TV-1 was unable to perform its required isolation function once Unit 2 entered a mode of applicability (Mode 3) on November 5, 2021, at 05:19, which was a condition prohibited by TS 3.3.2 with only 3 of 4 main turbine TVs operating as required. Additionally, the turbine trip response time requirement of 2.5 seconds could not be met with TV-1 closure time significantly greater than the required closure time of less than 1.1 seconds. The valves isolation function was restored on November 9, 2021, at 07:00, when the correct orifice block was installed, and testing was completed successfully. Licensee Event Report (LER) 05000328/2021-002-00 was submitted on January 6, 2022, in accordance with 10CFR50.73(a)(2)(i)(B) and 10CFR50.73(a)(2)(v) to report a condition prohibited by TS and a condition that could have prevented the fulfillment of a safety function needed to mitigate the consequences of an accident.
Corrective Actions: The licensee replaced the flushing block with the correct orifice block. Operability was restored after post-maintenance testing was completed with acceptance criteria met.
Corrective Action References: Condition report (CR) 1734714
Performance Assessment:
Performance Deficiency: The failure to ensure the correct orifice block was installed as required by QCM step 5.7 of preventive maintenance work instruction PM21626 was a performance deficiency.
Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Equipment Performance attribute of the Mitigating Systems cornerstone and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, slow closure of TV-1 could adversely impact the overall turbine trip response time requirement of 2.5 seconds as listed in the FSAR.
Significance: The inspectors assessed the significance of the finding using Appendix A, The Significance Determination Process (SDP) for Findings At-Power. The inspectors contacted a Region II Senior Reactor Analyst and confirmed that closure of the main turbine throttle valve was not credited in the Sequoyah SPAR (Standardized Plant Analysis Risk) model for any mitigating system success criteria, fault tree logic or otherwise relied upon for operator actions in response to modeled events. Additionally, the licensees Probabilistic Risk Analysis (PRA) Birnbaum importance measure for a completely failed (failure-to-close) turbine throttle valve was approximately 1E-08. The inspectors determined that the finding screened to Green because degraded (i.e., delayed) closure of the main turbine throttle valve did not alter any PRA assumptions, did not increase the risk associated with modeled functions and, therefore, maintained its SDP PRA functionality.
Cross-Cutting Aspect: H.2 - Field Presence: Leaders are commonly seen in the work areas of the plant observing, coaching, and reinforcing standards and expectations. Deviations from standards and expectations are corrected promptly. Senior managers ensure supervisory and management oversight of work activities, including contractors and supplemental personnel. The individual responsible for QCM oversight did not witness the QCM step performance as required.
Enforcement:
Inspectors did not identify a violation of regulatory requirements associated with this finding.
Licensee-Identified Non-Cited Violation 71114.04 This violation of very low safety significance was identified by the licensee and has been entered into the licensee corrective action program and is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Violation: Title 10 CFR Part 50.54(q)(2) requires that a holder of a nuclear power reactor operating license under this part, shall follow and maintain the effectiveness of an emergency plan that meets the requirements in Appendix E to this part and the planning standards of 10 CFR 50.47(b). Title 10 CFR Part 50.47(b)(4) requires a standard emergency classification and action level scheme, the bases of which include facility system and effluent parameters, is in use by the nuclear facility licensee, and State and local response plans call for reliance on information provided by facility licensees for determinations of minimum initial offsite response measures.
Contrary to the above, from July 3, 2018, until March 5, 2021, the licensee failed to maintain the effectiveness of its emergency plan and standard emergency classification scheme for system malfunctions during cold initiating conditions, CG1 & CS1. Specifically, in July 2018 the licensee implemented NRC-approved NEI 99-01, Revision 6, the emergency action level (EAL) scheme that utilized a calculated design output value of 60% for an emergency classification based on reactor vessel level indication system (RVLIS) percentage values. However, it was later discovered by the Operations Training Department that a value of 64% for RVLIS was used instead, which was the design output used by Emergency Preparedness (EP). The discrepancy degraded the licensees ability to declare emergencies, because the event classification would have occurred early under certain cold initiating conditions (Mode 5 and 6) using RVLIS. The RVLIS threshold values of 64% were overly conservative and therefore, could have caused a General Emergency to be declared early, and could have led to unnecessary protective action recommendations (PARs) being made to the public.
Significance/Severity: Green. A preliminary apparent violation (AV) was documented in the section Inspection Results of inspection report 2021-003 for this finding. The apparent violation was issued as a violation with the safety significance having to be determined. To disposition this finding the inspectors met with NRC management to discuss the significance of the finding during a pre-significance and enforcement review panel (pre-SERP). As a follow on to the pre-SERP, the inspectors further discussed the details of the finding to determine significance, using staff guidance in IMC 0609, Emergency Preparedness SDP, Appendix B, with the NRC headquarters EP program office. The discussions with the EP program office provided improved clarity on characterizing the significance of the AV finding. The pre-SERP members were informed that the significance of the violation did not warrant a SERP to be conducted.
The NRC process described above determined the significance of the finding using IMC 0609, Appendix B, Table 5.4-1. Although a CG1 or CS1 classification from RVLIS could result in an over-classification causing an unnecessary emergency declaration, numerous low probability conditions would need to happen to enable this to occur. For example, plant operations would have been aware of a challenge to maintain RVLIS level before the 64%
threshold, and would have taken steps to close containment, increase RCS level, or both.
Assuming containment closure was challenged, the plant operators would still have 30 minutes to increase the level above 64%. The 4% difference in RVLIS would not have significantly increased public risk with early evacuation, in that it wouldnt have significantly shortened the amount of time to classify the Initiating Condition. In the event both RVLIS recovery and containment closure were challenged at the same time, the emergency director (per the EALs) has the ability to declare a general emergency prior to reaching 64%. Thus, concern that the public could be placed at increased health risk without realizing the dose avoidance benefit of a necessary protective action, as a result of an unnecessary protective action from an overclassification, would no longer be an issue. Therefore, the regional management, inspectors, and the EP program office agreed to disposition the finding as very low safety significance (Green).
Corrective Action References: Condition Report (CR) 1673364 was written to document this issue, and the EAL was corrected on March 5, 2021. Eventually, another CR was written to initiate a causal evaluation (CR 1676064).
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
On April 26, 2022, the inspectors presented the integrated inspection results to Mr. Tom Marshall and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Procedures
0-PI-OPS-000-
006.0
Freeze Protection
Revision 67
Procedures
0-SO-250-2
20 Volt AC Vital Instrument Power System
Revision 75
Procedures
0-SO-67-1
Essential Raw Cooling Water
Revision 117
Procedures
0-SO-82-4
Diesel Generator 2B-B
Revision 66
Fire Plans
CON-0-706-00
Pre-Fire Plans - Control Building Elevation 706
Revision 6
Fire Plans
DGB-0-722-00
Pre-Fire Plans Diesel Generator Building - El. 722
Revision 7
Fire Plans
DGB-0-740.5-00
Pre-Fire Plans Diesel Generator Building - El. 740.5
Revision 6
Fire Plans
ERCW-0-688-00
Pre-Fire Plan Essential Raw Cooling Water Station,
Elevation 688
Revision 2
Fire Plans
ERCW-0-704-00
Pre-Fire Plan Essential Raw Cooling Water Station,
Elevation 704
Revision 2
Fire Plans
ERCW-0-720-00
Pre-Fire Plan Essential Raw Cooling Water Station,
Elevation 720
Revision 3
Corrective Action
Documents
CR 1732657
Fouling Limit Exceeded for 1A1/1A2 CCS Heat Exchangers
11/01/2021
Procedures
1-PI-SFT-070-
001.0
Performance Testing of Component Cooling Heat
Exchangers 1A1, 1A2
Revision 24
Work Orders
Perform a clam and mic inspection on 1A1 CCS Heat
Exchanger
2/14/2022
Miscellaneous
SEG#
OPL273E2221
Cycle 22-2 Simulator Exam
03/10/2022
Corrective Action
Documents
CR 1697239
Equipment Failure Investigation Checklist: Unit 1, B train
Motor Driven Auxiliary Feed Water Pump failure
08/20/2021
Engineering
Evaluations
Cause
Determination
Evaluation (CDE)
3154
1B MDAFW pump bearing failure
01/24/2022
Miscellaneous
CDE 3161
Maintenance rule functional failure of hydrogen mitigation
system
10/25/2021
Miscellaneous
SQN-DC-V-26.1
Design Criteria - Combustible Gas Control System
Revision 6
Miscellaneous
Standing Order:
ERCW Preferred Lineups during Components Outages
01/18/2022
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
SO-22-001
Procedures
0-GO-16
System Operability Checklist
Revision 31
Corrective Action
Documents
CR 1731919
Thru wall leak between 2-67-549B and main header
10/29/2022
Corrective Action
Documents
CR 1734714
Unit 2 TV-1 slow to close
11/08/2021
Corrective Action
Documents
CR 1734963
U2R24 lessons learned TV1 slow closure due to incorrect
orifice block
11/09/2021
Corrective Action
Documents
CR 1737790
Tech spec change request for TS LCO 3.3.2 function 5
11/22/2021
Corrective Action
Documents
CR 1753149
Perform POE on condition identified in CR 1731919
2/07/2022
Corrective Action
Documents
CR 1763164
Holding nut on Unit 2 Terry Turbine Electric Overspeed
device found removed
03/17/2022
Corrective Action
Documents
PER 990740
MCR ceiling cracked
2/21/2015
Engineering
Evaluations
2-DEM-067-006
Evaluate ERCW system for leak upstream of 2-67-549B
2/03/2022
Engineering
Evaluations
EWR 22-SNE-01-
2
Provide reasonable assurance of the Electrical Overspeed
functionality with the nut not securing the solenoid to the trip
mechanism
03/24/2022
Miscellaneous
Prompt investigation report for CR 1734714
11/09/2021
Miscellaneous
Replace throttle valve TV-1 actuator
11/10/2021
Miscellaneous
SQN-2-22-021
PRA evaluation response for Birnbaum value for main steam
throttle valve TV-1
03/17/2022
Operability
Evaluations
Past operability evaluation for CR 1734714
11/22/2021
Operability
Evaluations
Prompt
Determination of
Operability for CR
1753149
PDO for ERCW thru wall leak upstream of 2-VLV-067-0549B
03/04/2022
Miscellaneous
Test Report for
96000164-0412
Ametek Solidstate Controls test report for TVA-Sequoyah
amp dual chargers
07/22/2021
Corrective Action
CR 1747673
Alarm not received as expected during 1B EDG battery
01/14/2022
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Documents
charger PMT
Corrective Action
Documents
CR 1753331
1-MVOP-063-0153-B internal motor wire mashed
2/08/2022
Corrective Action
Documents
CR 1759467
Fire/Flood mode pump A-A flow and pressure below
acceptance criteria
03/04/2022
Procedures
0-SI-SXV-000-
206.0
Testing of Category A and B Valves after Work Activities,
Upon release from a Hold Order, or when Transferred form
Other Documents
Revision 7
Procedures
0-SI-SXV-063-
266.0
ASME Code Valve Testing
Revision 45
Procedures
2-SI-ICC-092-
N41.1
Channel Calibration of Power Range Nuclear Instrument
System Channel N41
Revision 37
Procedures
MMTP-141
Routine Inspection and Maintenance of Limitorque Motor
Actuators
Revision 4
Work Orders
21925421
0-PI-OPS-026-073.A, Fire/Flood Mode Pump A-A Flow Test
03/04/2022
Work Orders
21925711
1-PI-OPS-082-07.A, Load Shed of A-A Fire/Flood Mode
Pump
03/04/2022
Work Orders
SQN-1-BCTA-
003-0128-A, PM
20939
2/07/2022
Work Orders
SQN-19-989 Stage 2 PMT
Revision 1
Work Orders
Unit 2 N41 spiked bringing in rate trip and high flux alarms
03/10/2022
Calculations
SQTP002
ASME Section XI and OM Inservice Pump and Augmented
Pump Identification for the Second and Third Ten Year
Interval
Revision 9
Work Orders
20914194
Replace RA ERCW pump per C55 SQNL 187089
03/14/2022
71152A
Corrective Action
Documents
CR 1733842
Steam Line Pressure Transmitter 2-PI-1-9B out of tolerance
11/05/2021
71152A
Corrective Action
Documents
CR 1733966
2-PT-001-0009B Blockage
11/05/2021
71152A
Corrective Action
Documents
CR 1734092
Minor amounts of magnetite identified in Main Steam PT
sense lines
11/06/2021
71152A
Engineering
Evaluations
Equipment
Failure
CR 1734304 with extent of condition
2/08/2022
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Investigation
Checklist
71152A
Engineering
Evaluations
TVA Central Labs
Technical Report
BC20273
Plugged Pressure Transmitter Sense Line
2/14/2021