ML24136A248

NRC Presentation Slides for Topical Reports to Support SLR (5-22-24 Public Meeting)

ML24136A248
Person / Time
Site:	Robinson
Issue date:	05/22/2024
From:	Siva Lingam NRC/NRR/DNRL/NLRP
To:	Basta L Duke Energy Progress
Lingam, S., NRR/DNRL, 301-415-1564
References
Download: ML24136A248 (10)

Text

H. B. Robinson Steam Electric Plant, Unit 2 Request for Review of Reports to use Master Curve Methodology to Determine the Fracture Toughness-Based Reference Temperature May 22, 2024 Division of New and Renewed Licenses Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission

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Background===

• March 28, 2024 - Duke Energy Progress transmitted two reports o Requested NRC review and approval via Topical Report program by March 2025 o Reports support future SLRA for H.B. Robinson Unit 2 (second quarter of 2025)

PTS evaluation that will be provided in HBR2 SLRA Section 4.2.3 P-T limit curves evaluation that will be provided in HBR2 SLRA section 4.2.4.

Reactor Vessel Materials Surveillance AMP in HBR2 SLRA Appendix A2.1.19 and Appendix B2.1.19

• Reports provide unirradiated and irradiated material property values for RPV materials based on Master Curve (T0) methodology o WCAP-18909-NP, Revision 1, Determination of T0 for H.B. Robinson Unit 2 Heat number W5214, Linde 1092 Weld Metal Based on Unirradiated Data o WCAP-18933-NP, Revision 0, Determination of T0 for H.B. Robinson Unit 2 Heat number 5214 Weld Metal and Upper Shell Plate W10201-1 Based on Available Irradiated Data

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Background===

• NRC has previously approved use of T0 based approaches through Exemptions, for example Kewaunee Exemption Safety Evaluation (ADAMS Accession No. ML011210180)

All current regulations are predicated on Charpy data, and include discussion of use of Charpy data within the regulations Exemptions are required for 10 CFR 50.60; 10 CFR 50.61; and 10 CFR Appendices G and H

• NRC has endorsed 2019 ASME Code,Section XI of NB-2331 and Appendix G which both permit use of RTT0 for Code applications as alternatives to RTNDT Endorsement in 10 CFR 50.55a of Code applications of T0 data does not supersede requirements as written in 10 CFR 50.60; 10 CFR 50.61; and 10 CFR Appendices G and H None of the regulations listed above permit alternatives to use of RTNDT Compliance with 10 CFR 50.61 requires use of Charpy surveillance data

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Background===

• 10 CFR 50.90 License amendments may be necessary depending on specifics of UFSAR treatment of topic

• Robinson UFSAR Rev. 27 details compliance with 10 CFR 50.60; 50.61; and Appendices G and H in detail and with reference to RTNDT and Charpy results

• 10 CFR 50.59 allows changes in UFSAR if conditions are met This topic appears to fall under 50.59(c)(2)(viii); e.g. cannot be 50.59d

Review Under NRC Topical Report (TR) Program

• Calculation of material properties through Master Curve (T0) does not, in of itself, require a regulatory finding

• Licensees request does not appear to have a regulatory nexus Information provided would normally support a regulatory request

• Use of Master Curve as it interacts with 10 CFR 50.60 (Appendix G and H), and 10 CFR 50.61 would require regulatory findings (and Exemptions)

All regulations and appendices are predicated on use of Charpy or Charpy derived values, RTT0 cannot be substituted without Exemption 10 CFR 50.61 requires that RTNDT(u) be calculated in accordance with ASME Code NB-2331 or other NRC approved methodology ASME Code NB-2331 provides methodologies to calculate RTNDT(U) and RTT0, it does not state that they are equivalent and identical, nor does it state one may be substituted for the other freely (rather, RTT0 is presented as an alternative measure)

Regulatory Exemptions for RPV Integrity

• Implementation of Master Curve methodology requires 10 CFR 50.12 Exemptions

• Appendix H to 10 CFR Part 50 (i.e., RPV material surveillance program)

• Testing of Charpy specimens in existing capsules

• Future plans for irradiated surveillance data

• Use of surveillance data

• Pressurized Thermal Shock - 10 CFR 50.61

• Use of RTT0 in lieu of RTNDT

• Required use of surveillance data from Appendix H

• Appendix G to 10 CFR Part 50 - USE and PT Limits

• Direct reference to testing in accordance with Appendix H (e.g., Charpy specimens)

• Compliance with requirements for Upper Shelf Energy

• Use of RTT0 in lieu of RTNDT for unirradiated

• Use of RTT0 in lieu of RTNDT for PT-Limits

Potential Review Paths

• Submit 50.90 License Amendment and 50.12 Exemptions concurrent with SLRA

• NRC Regulatory Issue Summary 2014-06, Revision 1, Consideration Of Current Operating Issues And Licensing Actions In License Renewal

• LRA reviews that occur concurrently with licensing action reviews or other CLB changes may require extra consideration, resources, and review time, including reviews held in abeyance pending final determination of the impact of the CLB change on the LRA.

• Submit 50.90 License Amendment and 50.12 Exemptions Submit SLRA

• Two reviews in series

• Others - Discussion?

Key Take Aways

• Use of T0 will require Exemptions

• Robinson UFSAR appears to require amendment through 10 CFR 50.90 license amendment

Contact Information On Yee

+1-301-415-1905 On.Yee@nrc.gov Dan Widrevitz

+1-301-415-2620 Dan.Widrevitz@nrc.gov