IR 05000387/2024003
| ML24317A044 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 11/12/2024 |
| From: | Sarah Elkhiamy Division of Operating Reactors |
| To: | Berryman B Susquehanna |
| References | |
| IR 2024003 | |
| Download: ML24317A044 (1) | |
Text
November 12, 2024
SUBJECT:
SUSQUEHANNA STEAM ELECTRIC STATION, UNITS 1 AND 2 -
INTEGRATED INSPECTION REPORT 05000387/2024003 AND 05000388/2024003
Dear Brad Berryman:
On September 30, 2024, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Susquehanna Steam Electric Station, Units 1 and 2. On October 28, 2024, the NRC inspectors discussed the results of this inspection with Douglas LaMarca, Director, Strategic Planning, and other members of your staff. The results of this inspection are documented in the enclosed report.
One finding of very low safety significance (Green) is documented in this report. This finding involved a violation of NRC requirements. One Severity Level IV violation without an associated finding is documented in this report. We are treating these violations as non-cited violations (NCVs) 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 I; the Director, Office of Enforcement; and the NRC Resident Inspector at Susquehanna Steam Electric Station, Units 1 and 2.
If you disagree with a cross-cutting aspect assignment 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 I; and the NRC Resident Inspector at Susquehanna Steam Electric Station, Units 1 and 2. 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 (10 CFR) 2.390, Public Inspections, Exemptions, Requests for Withholding.
Sincerely, Sarah H. Elkhiamy, Chief Projects Branch 4 Division of Operating Reactor Safety
Docket Nos. 05000387 and 05000388 License Nos. NPF-14 and NPF-22
Enclosure:
As stated
Inspection Report
Docket Numbers:
05000387 and 05000388
License Numbers:
Report Numbers:
05000387/2024003 and 05000388/2024003
Enterprise Identifier: I-2024-003-0043
Licensee:
Susquehanna Nuclear, LLC
Facility:
Susquehanna Steam Electric Station, Units 1 and 2
Location:
769 Salem Blvd., Berwick, PA
Inspection Dates:
July 1, 2024 to September 30, 2024
Inspectors:
J. England, Senior Resident Inspector
E. Brady, Resident Inspector
S. Flanagan, Resident Inspector
J. Schussler, Senior Project Engineer
Approved By:
Sarah H. Elkhiamy, Chief
Projects Branch 4
Division of Operating Reactor Safety
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Susquehanna Steam Electric Station,
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.
List of Findings and Violations
Failure to Justify the Quality and Reliability for Agastat Relays Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000387/2024003-01 Open/Closed
[H.14] -
Conservative Bias 71111.12 A self-revealed finding of very low safety significance (Green) and non-cited violation (NCV) of Technical Specification (TS) 5.4.1.a, Procedures, and Regulatory Guide (RG) 1.33,
Appendix A, Section 9b, Procedures for Performing Maintenance, was identified because the licensee failed to establish an effective maintenance strategy to ensure the quality and reliability of Agastat control relays used in safety-related systems. As a result, the Susquehanna Steam Electric Station (SSES) Unit 1 C engineered safeguards system (ESS)bus alternate power supply breaker relay failed during surveillance testing on April 2, 2024, as original plant equipment in service for over 40 years.
Condition Prohibited by Technical Specifications Due to Slow Start Time of the D Emergency Diesel Generator Cornerstone Severity Cross-Cutting Aspect Report Section Not Applicable Severity Level IV NCV 05000387,05000388/2024003-02 Open/Closed Not Applicable 71153 A self-revealed Severity Level IV NCV of TS Limiting Condition for Operation (LCO) 3.8.1,
AC Sources - Operating, Condition B, for both Units 1 and 2, was identified when the D emergency diesel generator (EDG) failed to meet Surveillance Requirement (SR) 3.8.1.7.
Specifically, on September 12, 2023, the D EDG could not meet SR 3.8.1.7 start time requirements during surveillance testing, resulting in an unplanned TS LCO 3.8.1 entry. The inoperable condition occurred between August 17 and September 12, 2023, which was a duration greater than the LCO allowed outage time.
Additional Tracking Items
Type Issue Number Title Report Section Status LER 05000387,05000388/
2023-003-00 LER 2023-003-00 for Susquehanna Steam Electric Station, Units 1 and 2, D Diesel Generator Inoperable Due to Clogged Fuel Injectors 71153 Closed
PLANT STATUS
Unit 1 began the inspection period at rated thermal power. On September 8, 2024, the unit shut down for a maintenance outage to replace the B recirculation pump seal. The unit returned to rated thermal power on September 16, 2024, and remained at or near rated thermal power for the remainder of the inspection period.
Unit 2 began the inspection period at rated thermal power. On July 1, 2024, the unit down powered to 67 percent for work on the 2C reactor feed pump hydraulic power unit and returned to rated thermal power. On September 6, 2024, the unit down powered to 70 percent for scram time testing. The unit returned to rated thermal power on September 7, 2024, and remained at or near rated thermal power for the remainder of the 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 onsite 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
71111.04 - Equipment Alignment
Partial Walkdown (IP Section 03.01) (3 Samples)
The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:
- (1) Unit 2 B residual heat removal system during the week of July 8, 2024
- (2) Unit 2 control rod drive system on August 15, 2024
- (3) Unit 2 high-pressure coolant injection system on September 26, 2024
Complete Walkdown (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated system configurations during a complete walkdown of the Unit 2 standby liquid control system during the week of July 15, 2024.
71111.05 - Fire Protection
Fire Area Walkdown and Inspection (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 Common A, B, C, and D EDG rooms, fire areas 0-41A, 0-41B, 0-41C, and 0-41D, on July 2, 2024
- (2) Unit 2 reactor building, fire areas 2-5A-N, 2-5A-S, 2-5A-W, 2-5F, and 2-5G, on July 10, 2024
- (3) Unit 2 reactor building, reactor core isolation cooling pump room, high-pressure coolant injection pump room, division I core spray room, division II core spray room, division I residual heat removal pump room, division II residual heat removal pump room, and sump room, fire areas 2-1A, 2-1B, 2-1C, 2-1D, 2-1E, 2-1F, and 2-1G, on July 23, 2024
- (4) Unit 1 reactor building, emergency core cooling system rooms, fire areas 1-1A, 1-1B, 1-1C, 1-1D, 1-1E, 1-1F, 1-1G, 1-1H, and 1-1J, on August 13, 2024
- (5) Unit Common radioactive waste building, fire areas 0-61A, 0-61B, 0-61C, 0-61D, 0-61E, 0-61F, 0-61G, 0-61H, 0-62, 0-63A, 0-63B, 0-63C, 0-63D, 0-63E, and 0-63F, on August 22, 2024
71111.06 - Flood Protection Measures
Flooding (IP Section 03.01) (1 Sample)
- (1) The inspectors evaluated internal flooding mitigation protections on the 645-foot elevation in the Unit 2 reactor building on August 28, 2024.
71111.11Q - Licensed Operator Requalification Program and Licensed Operator Performance
Licensed Operator Performance in the Actual Plant/Main Control Room (IP Section 03.01) (1 Sample)
- (1) The inspectors observed Units 1 and 2 operations personnel during a high-risk evolution to build scaffold and troubleshoot lighting in the main control room on August 14, 2024.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
- (1) The inspectors observed a Unit 1 simulator evaluation that included an unisolable leak of the reactor core isolation cooling steam supply on August 19, 2024.
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 remain capable of performing their intended function:
- (1) Unit Common C EDG due to Agastat relay failure on April 2, 2024
- (2) Unit 1 error trending reactor building ventilation system condition monitoring events above limit on August 8, 2024
Quality Control (IP Section 03.02) (1 Sample)
The inspectors evaluated the effectiveness of maintenance and quality control activities to ensure the following structures, systems, and components remain capable of performing their intended function:
- (1) Unit Common commercial grade dedication of diesel fuel for the EDGs on August 22, 2024
71111.13 - Maintenance Risk Assessments and Emergent Work Control
Risk Assessment and Management (IP Section 03.01) (6 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 Common 'A' EDG for planned maintenance during the week of July 29, 2024
- (2) Unit 2 A residual heat removal pump out of service for planned maintenance during the week of August 5, 2024
- (3) Unit 2 emergency service water planned outage for pipe replacement during the week of August 26, 2024
- (4) Unit 1 planned maintenance outage for degraded B recirculation pump seal during the week of September 9, 2024
- (5) Unit Common emergency safety system transformer during planned outage for electrical maintenance during the week of September 16, 2024
- (6) Unit 2 elevated risk during planned activity on division 1 of core spray on September 30, 2024
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (6 Samples)
The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:
- (1) Unit 1 undervoltage relay 27A-20204 low out of specification on April 5, 2024
- (2) Unit 2 emergency safety system division 1 swingbus transfer slow to swap on May 29, 2024
- (3) Unit 1 division 1 emergency service water pipe wall thickness less than requirement on August 27, 2024
- (4) Unit 1 B reactor recirculation pump second stage seal degradation on August 28, 2024
- (5) Unit Common standby gas treatment system damper did not close when fan secured on September 4, 2024
- (6) Unit 1 control rod withdrawal out of sequence on September 12, 2024
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:
- (1) Unit 1 permanent modification - Engineering Change Package EC 2466869, Modify HV14F101 and 144F103 Operation to Allow for Modulation of the Reactor Water Cleanup Bottom Head Drain Flow to Minimize Flow Accelerated Corrosion in the Bottom Head Drain Line
71111.20 - Refueling and Other Outage Activities
Refueling/Other Outage (IP Section 03.01) (1 Sample)
- (1) The inspectors evaluated Unit 1 reactor recirculation pump seal maintenance outage activities from September 9 to 13, 2024.
71111.24 - Testing and Maintenance of Equipment Important to Risk
The inspectors evaluated the following testing and maintenance activities to verify system operability and/or functionality:
Post-Maintenance Testing (IP Section 03.01) (8 Samples)
- (1) Unit 1 charging water isolation valve, 147113-2655, for control rod 26-55 following replacement on July 30, 2024
- (2) Unit Common A EDG following mechanical governor replacement on July 31, 2024
- (3) Unit Common SO-024-001B data collection for linear reactor redesign on August 9, 2024
- (4) Unit 2 SO-253-004, Standby Liquid Control Flow Verification, following pump motor oil change on August 20, 2024
- (5) Unit 2 division 2 of emergency service water following pipe replacement on August 29, 2024
- (6) Unit 1 Part 21 cable replacement on valves HV143F031A, HV14182A, and HV14182B during the week of September 9, 2024
- (7) Unit 1 B reactor recirculation pump following seal replacement on September 11, 2024
- (8) Unit 1 bottom head drain throttling following maintenance outage on September 11, 2024
Surveillance Testing (IP Section 03.01) (2 Samples)
- (1) Unit 2 SO-251-A02, Quarterly Core Spray Flow Verification Division 1, on July 3, 2024
- (2) Unit 1 SE-164-305, 24-Month Calibration of Recirc MG Set Positioners - Electrical and Mechanical High-Speed Stops, on July 26, 2024
Inservice Testing (IP Section 03.01) (1 Sample)
- (1) Unit Common SO-030-A03, Quarterly Control Structure Chilled Water Flow Verification Loop A, on July 2, 2024
71114.06 - Drill Evaluation
Additional Drill and/or Training Evolution (1 Sample)
- (1) The inspectors evaluated a tabletop exercise in the Emergency Operating Facility at Unit 1 on August 14,
OTHER ACTIVITIES - BASELINE
===71151 - Performance Indicator Verification
The inspectors verified licensee performance indicators submittals listed below:
MS05: Safety System Functional Failures (SSFFs) (IP Section 02.04)===
- (1) Unit 1 July 1, 2023 through June 30, 2024
- (2) Unit 2 July 1, 2023 through June 30, 2024
71153 - Follow-up of Events and Notices of Enforcement Discretion Event Report (IP Section 03.02)
The inspectors evaluated the following licensees event reporting determinations to ensure it complied with reporting requirements.
- (1) Licensee Event Report (LER) 05000387 and 05000388/2023-003-00, "D Diesel Generator Inoperable Due to Clogged Fuel Injectors," (Agencywide Documents Access and Management System Accession No. ML23313A196): The inspection conclusions associated with this LER are documented in this report under the Inspection Results Section, Severity Level IV NCV. This LER is closed.
INSPECTION RESULTS
Failure to Justify the Quality and Reliability for Agastat Relays Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000387/2024003-01 Open/Closed
[H.14] -
Conservative Bias 71111.12 A self-revealed finding of very low safety significance (Green) and NCV of TS 5.4.1.a, Procedures, and RG 1.33, Appendix A, Section 9b, Procedures for Performing Maintenance, was identified because the licensee failed to establish an effective maintenance strategy to ensure the quality and reliability of Agastat control relays used in safety-related systems. As a result, the SSES Unit 1 C ESS bus alternate power supply breaker relay failed during surveillance testing on April 2, 2024, as original plant equipment in service for over 40 years.
Description:
The SSES Class 1E alternating current (AC) electrical power distribution system consists of two offsite power sources, normal and alternate. The onsite power sources are EDGs A, B, C, D and a fifth EDG E which can be substituted for any of the four. The AC distribution system includes four 4.16 kV ESS buses each having a primary and alternate offsite source of power as well as an onsite EDG. Each 4.16kV ESS bus is designed to automatically transfer from the normal to the alternate power supply if the normal supply breaker trips; likewise, an automatic transfer from alternate to normal power supply occurs after the alternate supply breaker trips. If neither offsite power supply is available, the EDG will start and provide power to the bus.
The licensee tests the transfer of 1C ESS bus from alternate power supply to normal supply in accordance with procedure SO-104-102, 4.16KV Class 1E BUS 1C 1A203 Offsite Supply Transfer Check. In April 2024 after performing steps 5.4.1 through 5.4.3, ESS bus 1C failed to transfer from alternate to normal. During the test, the 1A203-09 alternate power supply breaker failed to trip on an undervoltage condition, and the 1A203-01 normal power supply breaker did not close. When the system operates as designed, the Agastat relay 62A-20309 provides a time delay of 0.2 seconds, about 12 cycles, and then provides a trip function to open the 1A203-09 alternate power supply breaker.
The licensee conducted troubleshooting and determined that Agastat relay 62A-20309 in the 1A203-09 alternate supply breaker had failed. Contact 1-5 was open when it should have been closed. This relay must function for the loss of power instrumentation and relay to perform the safety function of tripping the associated breaker. This incorrect contact state resulted in a failure to meet TS SR 3.8.1.8 when the 1C ESS bus is being powered from 1A203-09 alternate supply. Furthermore, in this specific instance with the failed relay, the C EDG is inoperable when the 1C ESS bus is aligned to the 1A203-09 alternate power supply. Specifically, upon a loss of offsite power while on the alternate power supply 1A203-09, the relay failure would not allow 1A203-09 to open; and as a result, the C EDG would not power the Unit 1 C ESS bus. In the event of a loss of offsite power, manual operator actions could operate the breaker which will bypass the loss of power instrumentation and allow the breaker to trip and C EDG to power the bus.
The inspectors noted previous relay issues were conveyed to the industry in Information Notice 2012-006, Ineffective Use of Vendor Technical Recommendations. Specifically, an inspection team determined that the failure of a T3A Agastat relay at Calvert Cliffs installed in the EDG lube oil trip circuit demonstrated quality and reliability concerns after approximately 13 years due to timing drift after substituting a performance monitoring program for the Agastat relays. CR-1570017 reviewed this information notice, and the only actions identified during this review were related to document control of operating manuals.
ER-1001, Component Criticality Classification, defines this relay as Category 2, Non-Critical
- Important, because its failure would result in an unplanned shutdown LCO action of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or less. NDAP-QA-0415, Susquehanna Preventive Maintenance (PM) Program, Section 5.10, PM Templates, requires Electric Power Research Institute (EPRI) PM templates are to be used and any deviations from the EPRI templates need to be documented in the PM basis field. For non-critical relays operating with a high duty cycle, in a mild environment, the EPRI PM template recommends a 40-year replacement frequency. The licensee completed a PM frequency change for an environmental qualification replacement activity, extending the replacement from 40 to 60 years. The PM basis field contained per EQAR-052, Revision14, "the extended qualified life is 60 years. The inspectors reviewed EQAR-052 and found the PM change referenced the environmental qualification criteria as technical justification for the replacement extension.
The failed relay was installed as original plant equipment. The relay vendor noted the component is reliable up to 25,000 cycles or 10 years. The licensee noted the relays were not cycled often and had margin to the 25,000-cycle limit. The inspectors noted that the licensee limited their evaluation to the environmental qualification aspects which did not account for all applicable failure mechanisms, such as coil burnout, high contact resistance, mechanical binding, and lead failure to improve fuel performance during operation by mixing the water such that the fuel rods maintain the water film responsible for the heat transfer out of the rod and into the coolant.
For the 62A-20309 relay, the licensee elected to employ a value-based maintenance methodology of functional testing every 4 years and a separate replacement every 60 years for environmental qualification. The inspectors noted that the PM optimization guidance for PM change requests in licensee procedure NDAP-QA-0415, Attachment B, PM Change Request Process, is focused on maintaining the same level of reliability as assumed in the EPRI PM templates for Category 2 components and allows performance of value-based maintenance for Category 3 components with acceptable equipment performance. However, as outlined in EPRIs PM basis database, the omission of the recommended replacement PM would increase likelihood of failure by 25 percent.
Corrective Actions: The relay was replaced.
Corrective Action References: CR-2024-05363 and CR-2024-05427
Performance Assessment:
Performance Deficiency: The licensee failed to establish an effective maintenance strategy to ensure the quality and reliability of Agastat control relays used in safety-related systems and resulted in the failure of relay 62A-20309. NDAP-QA-0415, Section 5.10, PM Templates, states EPRI PM templates are to be used and any deviations from the EPRI templates need to be documented in the PM basis field. Specifically, the PM change evaluation only considered environmental qualification and did not review the relay vendor recommendations or consider all failure mechanisms.
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, the failure of the 62A-20309 relay resulted in the loss of the C ESS bus function to automatically transfer from the alternate offsite circuit to the normal offsite circuit, and adversely affected the aligned EDG's ability to automatically start with the Unit 1 C ESS bus aligned to the alternate power source. Additionally, the inspectors determined the performance deficiency was more than minor in accordance with IMC 0612, Appendix E, Examples of Minor Issues. Specifically, the inspectors determined this issue was similar to the more than minor criteria established in Example 13.a, Service Life.
Significance: The inspectors assessed the significance of the finding using IMC 0609, Appendix A, The Significance Determination Process for Findings At-Power, dated January 1, 2021. The inspectors performed a review of this finding using the guidance provided in IMC 0609, Appendix A, Exhibit 3, Mitigating Systems Screening Questions, and determined this finding is of very low safety significance (Green) because the questions in Exhibit 3, Section A, were answered No. Specifically, the failure of the 62A-20309 relay resulted in the loss of the C ESS bus function to automatically transfer to its normal power supply and adversely affected the reliability and capability of the automatic start of the aligned EDG if a loss of offsite power occurred. The inspectors noted control room operators could take manual action to open the alternate power supply breaker in an undervoltage condition.
Cross-Cutting Aspect: H.14 - Conservative Bias: Individuals use decision-making practices that emphasize prudent choices over those that are simply allowable. A proposed action is determined to be safe in order to proceed, rather than unsafe in order to stop. Specifically, while one criteria aspect, environmental qualification, indicates a component could withstand 60 years in service, further technical rigor and component health impacts should be considered and evaluated to proceed and ensure prudent PM choices are made.
Enforcement:
Violation: Susquehanna TS 5.4.1.a, Procedures, requires, in part, that written procedures shall be established, implemented, and maintained covering the applicable procedures recommended in RG 1.33, Quality Assurance Program Requirements (Operation),
Revision 2, Appendix A, February 1978. RG 1.33, Appendix A, Section 9, Procedures for Performing Maintenance, requires, in part, that procedures shall be established, implemented, and maintained. Section 9.b of Appendix A to RG 1.33 states, in part, that PM schedules should be developed to specify replacement of parts that have a specific lifetime.
The vendor specified lifetime for relay 62A-20309 was 25,000 cycles or 10 years from the date of manufacture, whichever occurs first. NDAP-QA-0415, Section 5.10, PM Templates, requires EPRI PM templates are to be used and any deviations from the EPRI templates need to be documented in the PM basis field. The PM optimization guidance for PM change requests in NDAP-QA-0415, Attachment B, PM Change Request Process, also notes that the program is focused on maintaining the same level of reliability as assumed in the EPRI PM templates for Category 2 components.
Contrary to the above, since 2017, the licensees maintenance strategy for Agastat 62A-20309 was to perform periodic functional testing and replacement every 60 years for environment qualification. Specifically, the 62A-20309 relay replacement frequency was extended from 40 to 60 years without adequately evaluating replacement part service life incorporating available relay industry operating experience or all applicable failure mechanisms. As a result, the loss of power instrumentation for the aligned EDG was rendered inoperable when the relay failed during surveillance testing on April 2, 2024, after being in service for over 40 years.
Enforcement Action: This violation is being treated as an NCV, consistent with Section 2.3.2 of the Enforcement Policy.
Condition Prohibited by Technical Specifications Due to Slow Start Time of the D Emergency Diesel Generator Cornerstone Severity Cross-Cutting Aspect Report Section Not Applicable Severity Level IV NCV 05000387,05000388/2024003-02 Open/Closed Not Applicable 71153 A self-revealed Severity Level IV NCV of TS LCO 3.8.1, AC Sources - Operating, Condition B, for both Units 1 and 2, was identified when the D EDG failed to meet SR 3.8.1.7. Specifically, on September 12, 2023, the D EDG could not meet SR 3.8.1.7 start time requirements during surveillance testing, resulting in an unplanned TS LCO 3.8.1 entry.
The inoperable condition occurred between August 17 and September 12, 2023, which was a duration greater than the LCO allowed outage time.
Description:
The licensee Class 1E AC electrical power distribution system AC sources consist of two offsite power sources and onsite standby power sources, (EDGs). The EDGs A, B, C, D, and a fifth EDG E can be used as a substitute for any one of the four. The EDG, when aligned to an ESS bus, starts automatically on a loss of coolant accident signal or on an ESS bus degraded voltage or under voltage signal. After the EDG starts, it automatically ties to its respective bus after offsite power is tripped. SR 3.8.1.7 ensures the EDG can be started from standby conditions and achieve minimum required voltage and frequency in 10 seconds, as well as maintain the required voltage and frequency when steady state conditions are reached. This SR provides reasonable assurance that the EDG can support the ESS bus sequential loading design. The 10-second start requirement supports assumptions in the design basis loss of coolant accident analysis of the updated final safety analysis report.
On September 12, 2023, the licensee was performing D EDG surveillance testing in accordance with SR 3.8.1.7. The D EDG reached the required frequency in 12.6 seconds, which exceeded the acceptance criteria of 10 seconds specified in SR 3.8.1.7. The licensee operators declared that SR 3.8.1.7 failed and entered TS 3.8.1, Condition B, on both Units 1 and 2 for the inoperable D EDG. The other EDGs (A, B, and C) were verified to be operable, and the operators substituted the E EDG for the D EDG. This substitution allowed the operators to exit the LCO 3.8.1, Condition B, on September 12, 2023.
Through troubleshooting, the licensee determined the failure to reach the required frequency within the acceptance criteria was the result of clogged fuel injectors. Furthermore, the licensee determined the condition of the inoperable D EDG was likely to have existed for longer than allowed by TS. Therefore, the event was determined to be reportable in accordance with Title 10 of the Code of Federal Regulations 50.73(a)(2)(i)(B) as a condition prohibited by TS. The licensee submitted LER 05000387 and 05000388/2023-003-00, D Diesel Generator Inoperable Due to Clogged Fuel Injectors, to document and report this issue.
The licensee completed a corrective action level 2 document, which attributed the direct cause of the slow start to clogged fuel injectors. The licensee did not identify an apparent cause. Their causal document notes that buildup of carbonaceous deposits on the fuel injectors nozzles can interfere with the spray pattern. Furthermore, these deposits are created by non-ideal, high or low, temperatures of the nozzle. Generally, these conditions are present when the engine is run at low or no-load conditions. The licensee noted their procedures follow vendor recommendations in each monthly surveillance test with gradual load increases, as well as an extended time at full load to ensure any harmful carbon or hydrocarbon deposits in the combustion chamber and exhaust are burned off. The licensees causal document annotated the monthly full load, less than full load, and total monthly run times. Additionally, the corresponding engine start times were annotated for each diesel run.
The inspectors independently reviewed the corrective action document, procedures, and the engine load and start duration data. Additionally, the inspectors reviewed the vendor manual applicable to engine maintenance, loading, and run times. The inspectors noted the direct cause of the engines slow start, not meeting the required frequency in 10 seconds, was due to clogged fuel injectors. This conclusion is supported by the maintenance and troubleshooting immediately following the initial failure to meet the required frequency timing.
The inspectors further noted the historical start times and full loading times do not display an adverse trend indicative of imminent fuel injector clogging. Based on the information and data reviewed by the inspectors, this TS violation was not reasonably foreseeable and preventable. Separately, the inspectors also noted that the licensee plans to take enhancement actions to evaluate their PM strategies and engine low load run times.
Corrective Actions: The fuel injectors were removed, cleaned, and the D EDG was run successfully meeting the frequency requirements. The licensee also plans to review PM enhancements.
Corrective Action References: CR-2023-14782, PCWO 2672065-1
Performance Assessment:
The NRC determined this violation was not reasonably foreseeable and preventable by the licensee and therefore is not a performance deficiency.
Enforcement:
Traditional enforcement is used to disposition violations that are not associated with Reactor Oversight Process findings.
Severity: The inspectors determined this issue constitutes a Severity Level IV violation, based on Enforcement Policy, Section 2.2.4, as well as its similarity to example 6.1.d.1 in the Enforcement Policy. Specifically, this issue involved the failure to comply with a TS action requirement.
Violation: Susquehanna TS LCO 3.8.1, requires, in part, that four EDGs be operable while in Modes 1, 2, or 3. If one required EDG is determined to be inoperable, it shall be returned to an operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. If not restored to an operable status, the unit shall be shut down and placed in Mode 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and Mode 4 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.
Contrary to this, from a date prior to and up to September 12, 2023, the D EDG was inoperable for longer than its TS allowed outage time, and the licensee had not placed the reactor in Mode 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> or Mode 4 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.
The disposition of this finding closes LER 05000387 and 05000388/2023-003-00, D Diesel Generator Inoperable Due to Clogged Fuel Injectors.
Enforcement Action: This violation is being treated as an NCV, consistent with Section 2.3.2 of the Enforcement Policy.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On October 28, 2024, the inspectors presented the integrated inspection results to Douglas LaMarca, Director, Strategic Planning, and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Plant
Status
Corrective Action
Documents
Resulting from
Inspection
CR-2024-12564
CR-2024-13055
Corrective Action
Documents
CR-2024-09974
CR-2024-13667
Corrective Action
Documents
Resulting from
Inspection
CR-2024-10684
Drawings
M-2146
PI&D Control Rod Drive Part A
Revision 35
M-2147
P&ID Control Rod Drive Part B
Revision 38
M-2148
Unit 2 PI&D Standby Liquid Control
Revision 28
M-2151
Susquehanna S.
Sheet 3
Revision 29
M-2156 SH 1
Unit 2 P&ID H.P.C.I. Turbine-Pump
Revision 32
M-2156 SH 2
Unit 2 P&ID H.P.C.I. Turbine-Pump
Revision 13
Miscellaneous
CL-249-0014
Unit 2 RHR System Division 2 Electrical
Revision 13
CL-249-0015
Unit 2 RHR System Division 2 Mechanical
Revision 25
CL-249-0018
Unit 2 RHR System Common
Revision 22
CL-252-0012
Valves - Unit 2 HPCI System
Revision 24
CL-253-0011
Unit 2 Standby Liquid Control System
Revision 9
CL-253-0012
Unit 2 Standby Liquid Control System
Revision 14
CL-255-0011
Unit 2 CRD Hydraulic System
Revision 7
CL-255-0012
Unit 2 CRD Hydraulic System
Revision 21
Procedures
Revision 31
Corrective Action
Documents
Resulting from
Inspection
CR-2024-10243
CR-2024-12448
CR-2024-12551
CR-2024-12561
Fire Plans
FP-0-DG-660-A
Diesel Building - El. 660
Revision 0
FP-0-DG-677-A
Diesel Building - El. 677
Revision 0
FP-0-DG-710-A
Diesel Building - El. 710
Revision 0
FP-1-RB-645
U1 Reactor Building - El. 645
Revision 2
FP-1-RB-645
Core Spray Pump Room Div. I
Revision 2
FP-1-RB-645
Sump Room
Revision 2
FP-1-RB-645
RHR Pump Room Div. I
Revision 2
FP-1-RB-645
RHR Pump Room Div. II
Revision 2
FP-1-RB-645
RCIC Pump Room
Revision 2
FP-1-RB-645
HPCI Pump Room
Revision 2
FP-1-RB-645
Core Spray Pump Room Div. II
Revision 2
FP-1-RW-646
RAD Waste - El. 646
Revision 0
FP-1-RW-676
RAD Waste - El. 676
Revision 0
FP-1-RW-691
RAD Waste - El. 691
Revision 0
FP-2-RB-645
U2 Reactor Building - El. 645
Revision 0
FP-2-RB-749
U2 Reactor Building - El. 749, Sheet 0
Revision 0
Corrective Action
Documents
AR-2023-09724
AR-2024-11630
Procedures
NDAP-QA-0409
Door Floor Plug and Hatch Control
Revision 24
Corrective Action
Documents
ACT-01-CR-05363
CR-2024-05363
CR-2024-09964
CR-2024-10246
CR-2024-12136
CR-2024-12679
Miscellaneous
P.O. 724589
P.O. 721038
Procedures
ER-1001
Component Criticality Classification
Revision 5
NDAP-QA-0413
Implementation of the Maintenance Rule
Revision 17
NDAP-QA-0413E
Maintenance Rule-Dispositioning Between a(1) and a(2)
Revision 5
NDAP-QA-0415
Susquehanna Preventive Maintenance (PM) Program
Revision 18
NEPM-QA-0300
Dedication of Commercial Grade Items and Services
Revision 6
Work Orders
PCWO 2719173-0
Corrective Action
Documents
CR-2024-13582
CR-2024-13602
CR-2024-14112
Corrective Action
Documents
Resulting from
Inspection
CR-2024-11469
CR-2024-11776
CR-2024-11780
CR-2024-11783
CR-2024-11785
CR-2024-12562
CR-2024-12578
CR-2024-12607
Procedures
NDAP-QA-0340
Protected Equipment Program
Revision 46
NDAP-QA-1902
Integrated Risk Management
Revision 51
Corrective Action
Documents
AR-2024-04004
AR-2024-12905
CR-2022-05118
CR-2024-05664
CR-2024-08674
CR-2024-12630
CR-2024-12991
CR-2024-13422
CR-2024-13445
Drawings
D107252
Susquehanna S.E.S. Unit 1 Schematic Diagram 4.16 kV Bus
1D Auxiliary Relay Control, Sheet 11
Revision 34
E106683
Common P&ID HVAC Control Diagram Control Structure,
Sheet 3
Revision 6
Procedures
NDAP-00-0333
Operational Decision-Making Process
Revision 31
NDAP-QA-0722
Surveillance Testing Program
Revision 35
NDAP-QA-0741
Surveillance Frequency Control Program
Revision 4
NDAP-QA-0745
Monitoring the Effects of Changes to the Surveillance
Frequency Control Program (SFCP)
Revision 2
NDAP-QA-1214
Nuclear Department Program for ASME Code Section XI
Repairs or Replacements and National Board Inspection
Repairs and Alterations
Revision 23
NEPM-QA-1170
Flaws in Class 3 Raw Water Systems
Revision 6
SM-104-002
kV 1A202 24-Month Undervoltage Channel Calibration
Revision 18
SO-104-001
Monthly Bus 1A201, 1A202, 1A203, 1A204, and 0B565
Degraded Voltage Channel Functional Test
Revision 20
SO-206-A01
Monthly ESS Division 1 Swingbus
Revision 10
Work Orders
PCWO 2717421-0
RTSV 2542431
RTSV-2726164
RTSV-2733080
Engineering
Changes
2466869
Modify HV14F101 and 144F103 Operation to Allow for
Modulation of the RWCU BHD Flow to Minimize FAC in the
Bottom Head Drain Line
Revision 1
Procedures
SO-100-011
Reactor Vessel Temperature and Pressure Recording (for
Heat Up/Cooldown, Mode 4, etc.)
Revision 29
Corrective Action
Documents
AR-2024-06506
AR-2024-12331
CR-2024-12307
Corrective Action
Documents
Resulting from
Inspection
CR-2024-11407
CR-2024-11408
CR-2024-11409
CR-2024-11410
CR-2024-11465
Procedures
MT-GM-090
Freeze Sealing of Piping Using the Rigid SF-2500
Superfreeze System
Revision 4
OP-024-004
Transfer and Test Mode Operation of Diesel Generator E
Revision 40
OT-024-145
Diesel Generator A Restoration
Revision 5
24-Month Calibration of Recirc MG Set Positioners Electrical
and Mechanical High-Speed Stops
Revision 5
SO-024-001B
Monthly Diesel Generator B Operability Test
Revision 30
SO-030-A03
Quarterly Control Structure Chilled Water Flow Verification
Loop A
Revision 33
SO-054-005A
Quarterly ESW/TBCCW and ESW/RBCCW Isolation Valve
Exercising Div 1
Revision 0
SO-054-017
Two-Year U2 RBCCW/TBCCW HX ESW RPI Checks
Revision 1
SO-161-001
Two-Year Reactor Water Cleanup (RWCU) Valve Exercising
Revision 23
SO-164-001
Plant Startup Reactor Recirculation Valve Exercising
Revision 21
SO-251-A02
Quarterly Core Spray Flow Verification Division 1
Revision 26
SO-253-004
SBLC Flow Verification
Revision 43
Local System Leakage Test of Reactor Recirculation Loops
A&B
Revision 13
Work Orders
PCWO 2717750-0
PCWO 2747512-0
RACT 2606001
RTPM 2685358
RTPM 2719142
RTSV 2567042
RTSV 2568411
RTSV 2719406
RTSV 2727123
RTSV 2741767
WO 2716110-0
WO 2732608-0
WO 2750765
71151
Corrective Action
Documents
AR-2024-02137
AR-2023-16005