IR 05000335/2024002

Integrated Inspection Report 05000335-2024002 and 05000389-2024002

ML24222A211
Person / Time
Site:	Saint Lucie
Issue date:	08/13/2024
From:	Renee Taylor NRC/RGN-II/DRP/RPB3
To:	Coffey B Florida Power & Light Co
References
IR 2024002
Download: ML24222A211 (13)

Text

SUBJECT:

SAINT LUCIE UNITS 1 & 2 - INTEGRATED INSPECTION REPORT 05000335/2024002 AND 05000389/2024002

Dear Bob Coffey:

On June 30, 2024, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Saint Lucie Units 1 & 2. On August 8, 2024, the NRC inspectors discussed the results of this inspection with Mr. Tim Falkiewicz, Regulatory Affairs Manager, 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. 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 violation or the significance or severity of the violation 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 Saint Lucie Units 1 & 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 II; and the NRC Resident Inspector at Saint Lucie Units 1 & 2.August 13, 2024 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, Ryan C. Taylor, Chief Reactor Projects Branch 3 Division of Reactor Projects Docket Nos. 05000335 and 05000389 License Nos. DPR-67 and NPF-16

Enclosure:

As stated

Inspection Report

Docket Numbers: 05000335 and 05000389

License Numbers: DPR-67 and NPF-16

Report Numbers: 05000335/2024002 and 05000389/2024002

Licensee: Florida Power & Light Company

Facility: Saint Lucie Units 1 & 2

Location: Jensen Beach, FL 34957

Inspection Dates: April 1, 2024 to June 30, 2024

Inspectors: S. Egli, Senior Construction Inspector J. Hickman, Senior Resident Inspector J.R. Reyes, Project Engineer S. Roberts, Project Engineer

Approved By: Ryan C. Taylor, Chief Reactor Projects Branch 3 Division of Reactor Projects

Enclosure SUMMARY

The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Saint Lucie 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

Failure to Perform Appropriate Maintenance on Safety Injection Tank Vent Valve Resulted in Degraded Reactor Coolant System Pressure Boundary Cornerstone Significance Cross-Cutting Report Aspect Section Initiating Events Green [H.12] - Avoid 71153 NCV 05000389/2024002-01 Complacency Open/Closed The inspectors reviewed a self-revealed Green finding and associated non-cited violation (NCV) of Saint Lucie Unit 2 Technical Specifications (TS) 5.4.1.a, Procedures, for the licensees failure to appropriately implement the requirements of engineering maintenance specification SPEC-M-196, Replacement of 2 and Under Safety Related Valves, as required by Regulatory Guide (RG) 1.33, "Quality Assurance Program Requirements, Appendix A, Section 9, Procedures for Performing Maintenance. Specifically, the licensee failed to implement fatigue prevention measures as detailed in SPEC-M-196 during replacement of 2A2 safety injection tank (SIT) vent valve V3801 (and associated reducer/piping) on September 13, 2021, and during weld failure repairs performed on V3801 and associated piping on December 16, 2023, which led to through-wall leakage in reactor coolant system (RCS) pressure boundary piping.

Additional Tracking Items

Type Issue Number Title Report Section Status LER 05000389/2024-001-00 Unit 2, Safety Injection Tank 71153 Closed Vent Through Wall Leakage

LER 05000389/2024-002-00 Unit 2, Safety Injection Tank 71153 Closed Vent Through Wall Leakage

PLANT STATUS

Unit 1 began the inspection period shut down for a planned refueling outage. On April 13, 2024, the unit was restarted and returned to rated thermal power (RTP) on April 16, 2024. On April 20, 2024, the unit was down powered to 75 percent (%) RTP due to failure of the 1A1 traveling water screen. Following repairs, the unit was returned to RTP on April 21, 2024, and remained at or near RTP for the remainder of the inspection period.

Unit 2 began the inspection period at RTP. On May 21, 2024, the unit was down powered to 92% RTP for 2A2 water box repairs, and following repairs, the unit was returned to RTP on May 29, 2024. On June 4, 2024, the unit was down powered to 92% RTP for 2A2 water box repairs and was subsequently tripped (shut down) to Mode 3 due to a 2B2 circulating water pump trip and lowering condenser vacuum. On June 6, 2024, the unit was restarted and returned to RTP on June 13, 2024. On June 17, 2024, the unit was down powered to 63% RTP for a hydraulic fluid leak on the main turbine. On June 18, 2024, the unit was shut down from 63% RTP to Mode 3 to perform repairs on the 2A2 water box and the main turbine hydraulic fluid leak. The unit was returned to RTP on June 27, 2024, where it remained for the rest 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, 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

Seasonal Extreme Weather Sample (IP Section 03.01) (1 Sample)

(1) The inspectors evaluated readiness for seasonal extreme weather conditions prior to the onset of hurricane season on May 31, 2024, for the following systems:

• Unit 1 and 2 intake cooling water (ICW)

• Unit 1 component cooling water (CCW)

• offsite and alternate alternating current power system

71111.04 - Equipment Alignment

Partial Walkdown Sample (IP Section 03.01) (4 Samples)

The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:

(1) Unit 1 low pressure safety injection shut down cooling system on April 2, 2024 (2) Unit 1 emergency boron injection flow paths to the RCS while in Mode 3: flow path from boric acid makeup tanks via a boric acid makeup pump though the charging pumps; flow path from the boric acid makeup tanks via a gravity feed valve through the charging pumps; and flow path from refueling water storage tank via 'A' charging pump on April 9, 2024 (3) Unit 1, 1B and 1C auxiliary feedwater (AFW) pumps while the 1A emergency diesel generator (EDG) was out of service (OOS) for testing on May 6, 2024 (4) Unit 1, 1A and 1B CCW following work performed on 1A and 1B CCW heat exchangers, on June 3, 2024

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, A and B EDG buildings on April 4, 2024 (2) Unit 2, building housing the component cooling water system on April 11, 2024 (3) Unit 1, 1A and 1B emergency core cooling system (ECCS) rooms on May 2, 2024 (4) Unit 1 / 2, A and B EDG and 2A and 2B diesel oil storage tank buildings on May 7, 2024 (5) Unit 2, 2A and 2B ECCS rooms on June 14, 2024

Fire Brigade Drill Performance Sample (IP Section 03.02) (1 Sample)

(1) The inspectors evaluated the onsite fire brigade training and performance during an unannounced fire drill, on May 10, 2024.

71111.06 - Flood Protection Measures

Flooding Sample (IP Section 03.01) (1 Sample)

(1) The inspectors evaluated the external flooding mitigation protections that prevent flooding into the unit 1 and unit 2 reactor auxiliary buildings. This inspection included the use operating experience smart sample 2007/02, Revision 3, Analysis of Flooding Vulnerabilities.

71111.07A - Heat Exchanger/Sink Performance

Annual Review (IP Section 03.01) (1 Sample)

(1) The inspectors evaluated readiness and performance of:

• 1A CCW heat exchanger during a clean, inspect, and eddy current test preventive maintenance activity on May 16, 2024

• 1B CCW heat exchanger during a clean, inspect, and eddy current test preventive maintenance activity on May 23, 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 and evaluated licensed operator performance in the control room during:

• Unit 1 startup, physics testing, and shut down on April 3, 2024

• Unit 1 startup from refueling outage SL1-32 on April 12, 2024

Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)

(1) The inspectors observed and evaluated a licensed operator just in time training evaluation in the control room simulator for SL1-32 reactor startup, which included a dropped rod casualty, on April 10, 2024.

71111.12 - Maintenance Effectiveness

Maintenance Effectiveness (IP Section 03.01) (1 Sample)

The inspectors evaluated the effectiveness of maintenance to ensure the following structures, systems, and components remain capable of performing their intended function:

(1) action request (AR) 2435832, condensate system a(1) evaluation after valve failure caused a manual reactor trip

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 2 online risk assessment while the steam bypass pressure control valves PCV-8801 and PCV-8805, and the 2A EDG were OOS on April 8, 2024 (2) Unit 2 online risk assessment while the 2B ICW header; HVE-41B intake structure exhaust fan; PCV-8801 and 8805 steam bypass pressure control valves; and the B-train high pressure safety injection valve HCV-3646 were OOS on April 18, 2024 (3) Unit 1 online risk assessment while the 1B EDG was OOS from April 29 - May 1, 2024 (4) Unit 1 elevated risk while 1A CCW heat exchanger was OOS for maintenance from May 13 - 16, 2024 (5) Unit 1 elevated risk while 1B CCW heat exchanger was OOS for pipe failure repair and entering risk informed completion time from May 20 - 30, 2024

71111.15 - Operability Determinations and Functionality Assessments

Operability Determination or Functionality Assessment (IP Section 03.01) (7 Samples)

The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:

(1) AR 02483492, 2A EDG cylinder 6 temperatures were below minimum guideline temperatures, review completed on April 10, 2024 (2) AR 02484167, Unit 1 ECCS HVE-9B exhaust fan, inlet damper D-16 failed to open when starting the fan, review completed on April 17, 2024 (3) changes to the status of inoperable technical specification required systems and equipment when the site implemented improved technical specifications (ITS), LAR 253 and 208, to operating license DPR-67 and NPF-16 on May 6, 2024 (4) AR 02486287, Unit 2 "C" auxiliary feed water trip and throttle valve, MV-08-3, actuator motor failure, review completed on May 22, 2024 (5) AR 02486108, Unit 1 reactor protective system cabinet "C" calibration and indication failed, review completed May 22, 2024 (6) AR 02486981, Unit 1 1B CCW strainer bypass pipe failed during backwash, review completed May 30, 2024 (7) AR 02488945, Unit 1 1B EDG engine A/C soakback pump failed, review completed June 20, 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) Engineering Change (EC) 299726, ICW piping modification, 1B CCW strainer bypass-install blank flange to isolate 20-CW-97 from 30-CW-79, review completed on June 13, 2024

71111.20 - Refueling and Other Outage Activities

Refueling/Other Outage Sample (IP Section 03.01) (1 Sample)

(1) The inspectors evaluated refueling outage SL1-32 activities from April 1, 2024 to April 14, 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 (PMT) (IP Section 03.01) (4 Samples)

(1) 2-OSP-25.09B, Train B ECCS Ventilation Surveillance Test, after failure of D-16 Fan 9B inlet damper on April 16, 2024 (2) 2-OSP-99.08B, B Train Quarterly Non-Check Valve Cycle Test, after inspection and diagnostic testing of HCV-3646 high pressure safety injection valve (WO 40861454)

on April 18, 2024 (3) 2-OSP-09.01C, 2C Auxiliary Feedwater Pump Code Run following repairs to trip and throttle valve (WO40978191), review completed on May 13, 2024

(4) WO 40949945-07, CCW HX 1A: Operations external leak check, following clean, inspect, eddy current test, and plug (WO 40949945-01), reviews completed on May 24, 2024

Surveillance Testing (IP Section 03.01) (4 Samples)

(1) 1-SMI-63.09B Channel B RPS and Engineered Safeguards System Channel Response Time Testing, review completed on April 2, 2024 (2) 1-PTP-81, Reload Startup Physics Testing, review completed on April 3, 2024 (3) 1-OSP-59.01A, 1A Emergency Diesel Generator Monthly Surveillance, review completed on April 17, 2024 (4) 1-OSP-69.14B, ESF - 18 Month Surveillance for EDG Start on SIAS Without LOOP and 24hr Load Run, completed on May 1, 2024

Inservice Testing (IST) (IP Section 03.01) (2 Samples)

(1) 2-OSP-03.06A, 2A Low Pressure Safety Injection Pump Code Run, review completed on May 8, 2024 (2) 2-OSP-09.01C, 2C Auxiliary Feedwater Pump Code Run, witnessed performance and review completed May 9, 2024

Reactor Coolant System Leakage Detection Testing (IP Section 03.01) (1 Sample)

(1) 1-OSP-01.03, Reactor Coolant System Inventory Balance, review completed on May 23, 2024

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) (2 Samples)

(1) Unit 1, April 1, 2023 through March 31, 2024 (2) Unit 2, April 1, 2023 through March 31, 2024

BI02: RCS Leak Rate Sample (IP Section 02.11) (2 Samples)

(1) Unit 1, April 1, 2023 through March 31, 2024 (2) Unit 2, April 1, 2023 through March 31, 2024

71152A - Annual Follow-up Problem Identification and Resolution

Annual Follow-up of Selected Issues (Section 03.03) (1 Sample)

The inspectors reviewed the licensees implementation of its corrective action program related to the following issue:

(1) AR 02480705, Unit 1 failed fuel in action level 1, and the following related AR's:

• AR 02485044 - Causal product for AR 02480705, failed MRC review

• AR 02480358 -Unit 1 reactor coolant system XE-133 trend

• AR 02481166 - Additional indications noted on the end-tie girder weldments

71153 - Follow Up of Events and Notices of Enforcement Discretion

Event Report (IP Section 03.02) (2 Samples)

The inspectors evaluated the following licensees event reporting determinations to ensure it complied with reporting requirements.

(1) LER 05000389/2024-001-00, Safety Injection Tank Vent Line Through Wall Leakage (ADAMS Accession No. ML24044A167). The inspection conclusions associated with this LER are documented in this report under Inspection Results Section 71153.This LER is Closed.

(2) LER 05000389/2024-002-00, Safety Injection Tank Vent Line Through Wall Leakage (ADAMS Accession No. ML24061A007). The inspection conclusions associated with this LER are documented in this report under Inspection Results Section 71153. This LER is Closed.

INSPECTION RESULTS

Failure to Perform Appropriate Maintenance on Safety Injection Tank Vent Valve Resulted in Degraded Reactor Coolant System Pressure Boundary Cornerstone Significance Cross-Cutting Report Aspect Section Initiating Events Green [H.12] - Avoid 71153 NCV 05000389/2024002-01 Complacency Open/Closed The inspectors reviewed a self-revealed Green finding and associated non-cited violation (NCV) of Saint Lucie Unit 2 Technical Specification (TS) 5.4.1.a, Procedures, for the licensees failure to appropriately implement the requirements of engineering maintenance specification SPEC-M-196, Replacement of 2 and Under Safety Related Valves, as required by Regulatory Guide (RG) 1.33, "Quality Assurance Program Requirements, Appendix A, Section 9, Procedures for Performing Maintenance. Specifically, the licensee failed to implement fatigue prevention measures as detailed in SPEC-M-196 during replacement of 2A2 safety injection tank (SIT) vent valve V3801 (and associated reducer/piping) on September 13, 2021, and during weld failure repairs performed on V3801 and associated piping on December 16, 2023, which led to through-wall leakage in reactor coolant system (RCS) pressure boundary piping.

Description: On August 18, 2021, during a Unit 2 reactor coolant pressure boundary walkdown, operators discovered a large accumulation of boric acid at the 2A2 SIT, which was determined to be originating at the V3801 pipe cap. On September 13, 2021, V3801 was replaced in accordance with EC 296696, which replaced the existing 8-pound 1 valve with a 16-pound 3/4 valve and a pipe reducer, due to the unavailability of a 1 vent valve.

On December 11, 2023, during a Unit 2 reactor containment building walkdown, dry boric acid was found on a pipe below valve V3801 and was classified as an inactive leak.

Subsequently, on December 15, 2023, a through-wall leak of class 1 piping segment SI-227 (upstream of V3801) was identified coming from the connection point for piping segments

SI-227 and SI-149. On December 16, 2023, V3801 was removed and replaced with a new 3/4 valve and pipe reducer, adding a 2:1 taper weld to the failed weld connection.

On December 26, 2023, operators identified lowering levels in the 2A2 SIT, and a 10 psig pressure drop during the shift. Subsequently, on January 3, 2024, Unit 2 was shut down to Mode 3 for containment entry to determine the source of lowering levels in the SIT. A visual inspection revealed a through-wall leak of class 1 piping segment SI-227, upstream of V3801 at the socket weld that was performed during the vent valve replacement on December 16, 2023. The impacted class 1 piping described was considered part of the reactor coolant pressure boundary. Upon the discovery of each of the through-wall leaks, the licensee made notifications to the NRC in accordance with 10 CFR 50.72(b)(3)(ii)(A) for the degraded condition related to the reactor coolant barrier through wall leak.

The licensees root cause evaluation concluded that the through wall leakage was caused by weld fatigue and solidification cracking. A failure analysis identified that the fatigue crack initiation and propagation were likely related to: internal pressure; bending stresses related to the weight of the valve and its mounting arrangement; system vibrations; and stresses due to differential thermal expansion of the valve assembly and the connection to the 12 safety injection piping. The licensee noted in the root cause evaluation that if the fatigue prevention measures (i.e., pipe configuration, valve weight considerations, and use of 2:1 taper welds)

as detailed in SPEC-M-196 had been followed, the weld configuration would not have been susceptible to fatigue and solidification cracking.

Corrective Actions: On January 5, 2024, V3801 was replaced with a new valve which incorporated all fatigue prevention recommendations of SPEC-M-196. The support was lengthened by 2 to allow room for 2:1 taper welds, and to allow relocating the supports from downstream of V3801 to upstream. Additionally, the vent valve assembly was returned to the original configuration (1 vent valve vice 3/4) that was replaced in 2021.

The licensee revised STD-W-002, General Welding Standard - Safety Related Piping, to require 2:1 taper welds and added guidance for the use of clamps when welding joints. The licensee also performed a review of the past five years of changes to reactor coolant pressure boundary lines of less than 2 diameter piping with restraints, that were not like-for-like replacements. The licensee walked down the equivalent valves on Unit 1 during refueling outage SL1-32 and identified no deficiencies.

Corrective Action References: AR 2475748 (Root Cause Evaluation). AR 2490506 was initiated to document this violation.

Performance Assessment:

Performance Deficiency: The inspectors determined that the licensees failure to implement the fatigue prevention measures of SPEC-M-196, as required by TS 5.4.1.a and RG 1.33, Appendix A, Section 9, to perform maintenance on V3801 and associated class 1 piping on September 13, 2021 and December 16, 2023, was within licensees the ability to foresee and correct, and therefore a performance deficiency.

Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Human Performance attribute of the Initiating Events cornerstone and adversely affected the cornerstone objective to limit the likelihood of events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. Specifically, the licensees failure to implement the fatigue prevention

measures of SPEC-M-196, resulted in non-isolatable through-wall leakage in RCS pressure boundary piping.

Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power. Using the Initiating Events Screening Questions found in Exhibit 1, Section A, the inspector determined that the finding screened to Green, the leak did not exceed the RCS leak rate for a small LOCA and did not prevent meeting the safety functions of the emergency core cooling system.

Cross-Cutting Aspect: H.12 - Avoid Complacency: Individuals recognize and plan for the possibility of mistakes, latent issues, and inherent risk, even while expecting successful outcomes. Individuals implement appropriate error reduction tools. Specifically, the site failed to recognize the latent issues caused by the engineering change in 2021, which added additional valve weight and length, and a 1 to 3/4 pipe reducer but did not consider the potential for weld fatigue and solidification cracking due to the change. This complacency resulted in two separate incidents of weld failures on the same class 1 piping segment, SI-227.

Enforcement:

Violation: TS 5.4.1.a requires in part that written procedures shall be established, implemented, and maintained covering the applicable procedures recommended in RG 1.33, Revision 2, Appendix A. RG 1.33, Appendix A, Section 9, Procedures for Performing Maintenance, requires in part that maintenance that can affect the performance of safety-related equipment should be properly preplanned and performed in accordance with written procedures, documented instructions, or drawings appropriate to the circumstances.

Engineering maintenance specification SPEC-M-196, Section 3.6, Spatial Envelope, Piping Configuration, and Weight, contained guidance for the installation of 2 and under safety-related vent valves.

Contrary to the above, on September 13, 2021, and December 16, 2023, the licensee failed to implement the fatigue prevention measures of SPEC-M-196 to perform maintenance on 2A2 SIT vent valve V3801 and associated class 1 piping, which resulted in through-wall leakage in RCS pressure boundary piping.

Enforcement Action: This violation is being treated as a non-cited violation, 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 July 25, 2024, the inspectors presented the integrated inspection results to Mr. Rob Craven, Site Vice President, and other members of the licensee staff.

• On August 8, 2024, the inspectors presented updated integrated inspection results to Mr. Tim Falkiewicz, Regulatory Affairs Manager, and other members of the licensee staff.

10