A Code Case Concerning the Effect of Embrittlement on Index Temperature Metrics

Abstract

Abstract The ASME Section XI Working Groups on Operating Plant Criteria (WGOPC) and on Flaw Evaluation (WGFE) have undertaken an effort to develop a new Code Case (Record # 19-1113) to address the following inquiry: What method(s) are acceptable for obtaining RTNDT, RTTo and/or T0 that account for embrittlement for analytical evaluations performed in accordance with Nonmandatory Appendices A, E, G, or K in lieu of the current requirements of these Appendices? Accounting for embrittlement in Code calculations in an appropriate manner is a critical element to the operating safety of nuclear power plants. The intent of responding to this inquiry is to ensure that Code guidance on this matter is comprehensive, up-to-date with the current state of knowledge and applications, and appropriate for international use. The work on the Code Case aims to unify guidance on the following topics throughout the Code, and to fill gaps as needed: • Source of embrittlement data, • Forecasting of embrittlement trends, • Accounting for embrittlement in the inter-relationships between various toughness properties, and • Accounting for uncertainties associated with embrittlement. This paper outlines the overall structure of the Code Case, and summarizes the progress achieved to date.