ML18267A093
| ML18267A093 | |
| Person / Time | |
|---|---|
| Issue date: | 09/24/2018 |
| From: | Tregoning R L NRC/RES/DE |
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| Shared Package | |
| ML18267A083 | List: |
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| Download: ML18267A093 (5) | |
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© 2018 Electric Power Research Institute, Inc. All rights reserved.Gary L. StevensTechnical Executive, EPRINRC Public Meeting on Environmentally Assisted Fatigue (EAF) Research and Related ASME ActivitiesSeptember 25, 2018NRC Headquarters -Rockville, MDOverview of EPRI Updated Gap Report 2© 2018 Electric Power Research Institute, Inc. All rights reserved.Environmentally Assisted Fatigue Gap Analysis and Roadmap for Future Research, November 2012(Product ID 1026724)Gap prioritization performed by industry expert panel21 gaps identified as high priority7 hypotheses proposed to explain the apparent discrepancy between test data and field experienceThe intent of the report is to identify knowledge gaps that can be used to direct research effortsReport is publicly available2012 Gap ReportOLD KNOWLEDGE GAPS 3© 2018 Electric Power Research Institute, Inc. All rights reserved.Environmentally-Assisted Fatigue; Knowledge Gap Analysis -Update and Revision of the EAF Knowledge Gaps (Product ID 3002013214)Gaps were reviewed in the light of recent researchBased on direction of industry R&D programsA revised and categorized list of gaps was developed:Remove overlap and increase ease of useEmphasize collaboration between testing and assessmentRevised gaps direct research without Publication expected by end of September 2018; report will be publicly availableThe EAF Knowledge Gaps were recently updated to reflect the most recent research and understandingUpdated Gap ReportPaper and presentation was given at Fontevraud 9, September 17-20, 2018 4© 2018 Electric Power Research Institute, Inc. All rights reserved.Since the 2012 EAF Knowledge Gap Report, there has been extensive progress in EAF research aimed at closing some of the key gaps and developing improved assessment methodologies for EAF in LWR environmentsThe main focus has been on austenitic stainless steels in PWR coolantSome of the most significant and promising new assessment methods and supporting data are at differing stages of development:Recognition that transference factors differ between air and LWR environments so a proportion of Fenis already included in the ASME III design curve (Fen-integrated, Fen-threshold)Weighting models for assessing both fatigue life and crack growth for complex and non-isothermal transients (SNW, WKR)Consideration of using lower transference factors on stress and on lifeUse of effective Kfor crack growth calculation for transients with a compressive portionRecognition of strain gradient effects for thermal transients which support the development of a Total Life Assessment methodologyA revision of the Knowledge Gap report includes a revised, condensed, and categorized listing of the remaining knowledge gapsThis publicly available EPRI report is in final publicationConclusions of Updated Gap Report 5© 2018 Electric Power Research Institute, Inc. All rights reserved.