ML23144A025

APS Presentation Slides for Pre-Submittal Meeting on 5/25/23, Przr Surge Line

ML23144A025
Person / Time
Site:	Palo Verde
Issue date:	05/25/2023
From:	Arizona Public Service Co
To:	Plant Licensing Branch IV
Lingam S, 301-415-1564
References
EPID L-2023-LRM-0031
Download: ML23144A025 (1)

Text

Pre-Submittal Meeting: Management of Environmentally-Assisted Fatigue of Pressurizer Surge Line May 25, 2023

Agenda

• Introduction

• License Renewal Commitment

• Pressurizer Surge Line Fatigue Monitoring and Projections

• ASME Section XI, Appendix L Evaluation

• Precedents

• Submittal Timeline 2

License Renewal Commitment UFSAR 19.2.1 Monitor the effects of environmentally assisted fatigue (EAF) of the Reactor Coolant Pressure Boundary (RCPB) in the Period of Extended Operation. When any monitored location fatigue usage including EAF projects to exceed 1.0 corrective actions will be established using one or more of the following:

1) Determine whether the scope of the enhanced Metal Fatigue of Reactor Coolant Pressure Boundary program must be enlarged to include additional affected reactor coolant pressure boundary locations. This determination will ensure that other locations do not approach design limits without an appropriate action.

2) Adjust fatigue monitoring methods to confirm continued conformance to the code limit.

3) Repair/modify the component.

4) Replace the component.

5) Perform a more rigorous analysis of the component to demonstrate that the design code limit will not be exceeded.

6) Modify plant operating practices to reduce the fatigue usage accumulation rate.

7) Perform a flaw tolerance evaluation and impose component-specific inspections, under ASME Section XI, Appendices A or C (or their successors) and obtain required approvals from the regulatory agency.

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Pressurizer Surge Line Fatigue Monitoring and Projections

• Palo Verde utilizes FatiguePro4 (FP4) software provided by Structural Integrity Associates to monitor fatigue of the RCPB, including the effects of EAF.

• The surge line is monitored using the FP4 Stress-based Fatigue (SBF) module for the surge line hot leg elbow sentinel location.

• Most recent surge line elbow cumulative usage (Uen) 60-year projections:

• Unit 1 - 4.27

• Unit 2 - 4.66

• Unit 3 - 5.86 4

ASME Section XI, Appendix L Evaluation Palo Verde intends to manage the fatigue effects of the surge line by periodic inspections at a frequency determined by an Appendix L, Operating Plant Fatigue Assessment evaluation.

• Establish loading conditions and 3-D finite element model.

• Determine allowable flaw sizes (Section XI, Appendix C) for surge line welds.

• Establish postulated initial flaw sizes per Appendix L.

• Perform fatigue crack growth analyses using linear elastic fracture mechanics (LEFM) techniques to determine the time for the postulated initial flaw to grow to the allowable flaw size.

• Set inspection intervals based on the crack growth analyses.

• Using similar methodology, demonstrate fatigue crack growth and inspection intervals for elbow base metal are bounded by the Appendix L evaluation of the surge line welds.

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Appendix L Evaluation Results Semi-Elliptical Axial Flaw 360-Degree Circumferential Flaw Weld ID Paths Flaw size in 10 Years Flaw size in 10 Years Allowable N, Allowable N, a/t* years a/t* years a, inch c, inch** a/t a, inch a/t P1 0.2336 0.5972 0.1781 0.75 100 0.2500 0.1906 0.2523 22 P2 0.2321 0.5963 0.1769 0.75 100 0.2513 0.1915 0.2523 21 20B P3 0.2443 0.6037 0.1862 0.75 100 0.2660 0.2027 0.2523 17 P4 0.2332 0.5966 0.1778 0.75 100 0.2475 0.1886 0.2523 22 P1 0.2575 0.6158 0.1963 0.75 100 0.2466 0.1879 0.3155 34 P2 0.2324 0.5978 0.1772 0.75 100 0.2702 0.2059 0.3155 24 20E P3 0.2537 0.6128 0.1934 0.75 100 0.3173 0.2418 0.3155 15 P4 0.2603 0.6183 0.1984 0.75 100 0.3296 0.2512 0.3155 14 P1 0.2302 0.5953 0.1755 0.75 100 0.2505 0.1909 0.4282 52 P2 0.2304 0.5954 0.1756 0.75 100 0.2474 0.1885 0.4282 57 27 P3 0.2274 0.5930 0.1733 0.75 100 0.2474 0.1885 0.4282 57 P4 0.2316 0.5962 0.1765 0.75 100 0.2833 0.2159 0.4282 29 P1 0.2635 0.6213 0.2008 0.75 99 0.2487 0.1896 0.3117 32 P2 0.2455 0.6068 0.1871 0.75 100 0.2474 0.1886 0.3117 34 30B P3 0.2447 0.6057 0.1865 0.75 100 0.2474 0.1886 0.3117 34 P4 0.2469 0.6074 0.1882 0.75 100 0.3236 0.2466 0.3117 14 P1 0.2623 0.6203 0.1999 0.75 100 0.2485 0.1894 0.2957 29 P2 0.2456 0.6068 0.1872 0.75 100 0.2661 0.2028 0.2957 23 30E P3 0.2471 0.6076 0.1883 0.75 100 0.3191 0.2432 0.2957 13 P4 0.2490 0.6091 0.1898 0.75 100 0.3206 0.2444 0.2957 13 P1 0.2389 0.6009 0.1821 0.75 100 0.2464 0.1878 0.4238 56 P2 0.2357 0.5994 0.1796 0.75 100 0.2537 0.1934 0.4238 49 50B P3 0.2511 0.6102 0.1914 0.75 100 0.2487 0.1896 0.4238 52 P4 0.2471 0.6074 0.1884 0.75 100 0.2978 0.2270 0.4238 25 P1 0.2437 0.6042 0.1858 0.75 100 0.2468 0.1881 0.4314 57 P2 0.2358 0.5994 0.1797 0.75 100 0.2474 0.1886 0.4314 57 50E P3 0.2517 0.6107 0.1918 0.75 100 0.2482 0.1891 0.4314 55 P4 0.2469 0.6073 0.1882 0.75 100 0.2999 0.2286 0.4314 25 P1 0.2415 0.6029 0.1841 0.75 100 0.2539 0.1935 0.4512 51 P2 0.2373 0.6000 0.1808 0.75 100 0.2522 0.1922 0.4512 55 60B P3 0.2385 0.6009 0.1818 0.75 100 0.2488 0.1896 0.4512 60 P4 0.2304 0.5949 0.1756 0.75 100 0.2808 0.2141 0.4512 30 P1 0.2317 0.5964 0.1766 0.75 100 0.2543 0.1938 0.4207 47 6 60E P2 0.2315 0.5959 0.1764 0.75 100 0.2609 0.1989 0.4207 38 P3 0.2453 0.6052 0.1870 0.75 100 0.2504 0.1909 0.4207 51 P4 0.2406 0.6022 0.1834 0.75 100 0.2584 0.1969 0.4207 40

Elbow Base Metal Evaluation Results Location Semi-Elliptical Axial Flaw (Flank)

(Elbow Flank) Flaw size in 10 years Allowable N, a, inch C, inch a/t a/t* years Elbow 60 0.3520 0.7192 0.2683 0.75 50 Elbow 30 0.2982 0.6548 0.2273 0.74 72 7

Periodic Inspection Program

• All surge line welds and elbows will be inspected at a 10-year frequency (the maximum allowed by Appendix L).

• Volumetric examinations using Acceptance Criteria established in ASME Section XI, Subsection IWB, for welds and Section III, NB-2500, for elbow base metal.

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Surge Line Elbow and Weld Locations 9

Precedents

• Turkey Point, Units 3 and 4, License Renewal Commitment, Submittal of Pressurizer Surge Line Welds Inspection Program (ADAMS Accession Numbers ML12152A156 and ML13141A595).

• St. Lucie, Units 1 and 2 - License Renewal Commitment, Submittal of Pressurizer Surge Line Welds Inspection Program (ADAMS Accession Numbers ML15314A160 and ML16235A138).

• Arkansas Nuclear One, Unit 2, License Renewal Pressurizer Surge Line and Safety Injection Nozzle Inspection (ADAMS Accession Number ML18144A970 and ML19074A028).

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Submittal Timeline

• Submit to NRC June 2023

• Estimated 1-yr NRC review time

• Implement within 120-days of NRC approval Period of Extended Operation Unit 1: June 1, 2025 Unit 2: April 24, 2026 Unit 3: November 25, 2027 11

Questions