ML26054A317
| ML26054A317 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  (DPR-067, NPF-016) |
| Issue date: | 02/13/2026 |
| From: | Nextera Energy |
| To: | Herrera-Torres M NRC/NRR/DORL/LPL2-2 |
| Jordan N | |
| References | |
| EPID L-2026-LRM-0010 | |
| Download: ML26054A317 (11) | |
Text
Proprietary &
Confidential St. Lucie Nuclear Plant, Units 1 and 2 Pre-Submittal Meeting License Amendment Request (LAR) 26-01 Extended Leak-Before-Break (eLBB)
February 13, 2026 February 13, 2026
Proprietary & Confidential FPL Project Team 2
Shane Webb - Fleet Programs Engineer Edd Ong - Manager, Fleet Inspection Programs Maribel Valdez - Manager, Fleet Licensing Jarrett Mack - Fleet Licensing Engineer
Proprietary & Confidential 3
LAR Purpose and Benefits Applicable Requirements Current Licensing Basis / Proposed Change Analysis Methodology Leak Detection Capabilities Conclusions / Schedule Questions Meeting Agenda
Proprietary & Confidential 4
LAR expands LBB to certain Class 1 auxiliary piping connected to the RCS.
The current NRC approved leak-before-break (LBB) analysis for St. Lucie Unit 1 and Unit 2 allows for exclusion of postulated pipe breaks in RCS main loop piping from the licensing and design basis.
St. Lucie License Amendment Request (LAR) 26-01 expands the Unit 1 and Unit 2 LBB analysis to certain Class 1 auxiliary system piping connected to the Reactor Coolant System (RCS).
Approval of the LAR will significantly reduce the postulated loads resulting from LOCA events.
Specifically, the proposed change allows for increased analytical margin on the St. Lucie Unit 1 reactor vessel core barrel.
Additional benefits may be identified during the implementation phase, e.g.,
- Whip restraint removal
- Increase Time-Limited Aging Analysis (TLAA) margin for specific components LAR Purpose and Benefits
Proprietary & Confidential 5
Meeting the requirements of GDC 4 and the guidance of SRP 3.6.3 provides assurance that that the probability of pipe rupture in qualifying piping systems is extremely low.
General Design Criteria (GDC) 4 of 10 CFR 50, Appendix A, states that the dynamic effects associated with postulated pipe ruptures in nuclear power units may be excluded from the design basis when analyses reviewed and approved by the Commission demonstrate that the probability of a fluid system piping rupture is extremely low under conditions consistent with the design basis for the piping.
Standard Review Plan (SRP) 3.6.3, Leak-Before-Break Evaluation Procedures, of NUREG-0800 provides specific guidance on screening criteria, safety margins, and analytical methods for the piping systems to be qualified for the application of LBB, including guidance for acceptable RCS leakage detection systems.
Regulatory Guide (RG) 1.45, Revision 1, Guidance on Monitoring and Responding to Reactor Coolant System Leakage, describes acceptance criteria for the RCS leakage detection systems.
States that RCS leakage detection should include multiple, diverse, and redundant means of leakage detection, and that plant procedures should specify operator actions in response to leakage rates less than technical specifications limits including identifying leakage source and responding to leakage rate trends.
Applicable Requirements
Proprietary & Confidential 6
In 1993, the NRC approved for St. Lucie the LBB analysis performed by the Combustion Engineering Owners Group (CEOG) (ADAMS Accession No. ML20138E042)
The analysis demonstrated that any potential leaks that might develop in the RCS primary coolant loop piping can be detected by plant monitoring systems before a postulated crack causing the leak would grow to unstable proportions.
Current Licensing Basis / Proposed Change Proposed change expands the Unit 1 and Unit 2 LBB analysis to the RCS auxiliary piping lines:
Pressurizer surge lines attached to the hot leg RCS piping Shutdown cooling (SDC) attached to the hot leg RCS piping Safety injection tank (SIT) lines attached to the cold leg RCS piping LAR analytically demonstrates that a through-wall crack in RCS auxiliary piping will leak at a detectable rate for a significant amount of time before it results in a catastrophic rupture.
Proprietary & Confidential 7
Analysis Methodology Uses Westinghouse WCAP-18618-P, St. Lucie Units 1 & 2 Subsequent License Renewal: Technical Justification for Eliminating Auxiliary Piping Rupture as the Structural Design Basis Using Leak-Before-Break Methodology.
Demonstrates through fracture mechanics and fatigue crack growth analysis, LBB applicability using the recommendations and criteria proposed in SRP 3.6.3.
Provides a fracture mechanics demonstration of the auxiliary line piping integrity for St. Lucie consistent with the NRCs position for exemption from consideration of dynamic effects (See Final Rule, FR 52 207).
Computer codes used in the evaluation were validated by Westinghouse for all LBB applications.
Analysis modeled pressurizer surge, SDC, SIT lines utilizing the recommendations and criteria proposed in SRP 3.6.3.
The analysis concluded that the leak rate calculations, fracture mechanics analysis, and fatigue crack growth assessment conservatively meet the analytical margins requested by SRP 3.6.3 for:
Margin on Leak Rate Margin on Flaw Size Margin on Loads
Proprietary & Confidential 8
St. Lucie capable of detecting 0.1 gpm unidentified leakage, i.e., well below SRP recommendation.
RCS Leakage Detection and Monitoring System Requirements Allowable flaw size requires a margin of 10 [SRP 3.6.3]
RCS leakage detection system includes multiple, diverse, and redundant means of leakage detection [RG 1.45, Rev.1]
Plant procedures specify operator actions in response to leakage rates less than technical specifications limits including actions for confirming the existence of a leak, identifying the leakage source, increasing the frequency of monitoring, verifying the leakage rate, responding to leakage rate trends, etc. [RG 1.45, Rev.1]
System Capability and Sensitivity The calculated allowable flaw size correlates to 2.5 gpm leak rate.
Applying SRP margin factor of 10 results in a detectable leakage rate requirement of 0.25 gpm.
St. Lucies leak detection systems are capable of detecting leak rates much smaller than 0.25 gpm. Site procedures include progressive action levels for unidentified leakage at a 0.10 gpm leak rate.
Leak Detection Capabilities
Proprietary & Confidential 9
LAR does NOT propose a reduction of the T.S. required unidentified leak rate limit of 1.0 gpm.
Existing Technical Specification (TS) requirements LCO 3.4.13 for RCS unidentified leakage and LCO 3.4.15 for RCS leakage detection instrumentation are consistent with 10 CFR 50.36(c)(2)(ii), Criterion 2 and Criterion 1 requirements, respectively, for TS inclusion as LCOs.
SR 3.4.13-1 for RCS operational leakage detection, and SRs 3.4.15-1, 3.4.15-2, 3.4.15-3, and 3.4.15-4 for RCS leakage detection instrumentation are consistent with the 10 CFR 50.36(c)(2)(ii) requirements for TS surveillances.
Thereby, no changes are necessary in support of the proposed LBB expansion to the subject Class 1 pressurizer surge, SDC, SIT system piping.
Industry Precedent Waterford 3 Amendment No. 232, Approval of Leak-Before-Break of the Pressurizer Surge Line (TAC NO.
ME3420)(ADAMS Accession No. ML110410119)
Leak Detection Capabilities, cont.
Proprietary & Confidential 10 LAR would expand LBB applicability to the pressurizer surge, shutdown cooling (SDC),
and safety injection tank (SIT) system piping consistent with the LBB evaluation procedures prescribed in SRP Section 3.6.3.
WCAP-18618-P demonstrates through fracture mechanics and fatigue crack growth that that the probability of pipe rupture in qualifying piping systems is extremely low.
St. Lucies leakage detection systems and processes adequately satisfy the recommendations of RG 1.45, Revision 1.
LAR submittal in February/March 2026.
Request review and approval within one year of satisfactory application acceptance.
LAR to be implemented within 90 days of Amendment issuance.
Audit portal available for virtual audit.
Conclusions Schedule
Proprietary & Confidential 11 Questions