Full Description

WRC Bulletins 457, 458 and 459 form an integral set documenting the development of an alternative to the ASME Section III RTNDT procedure based on To, and the development of an ASME Code Case. The three bulletins should be purchased as a set. WRC Bulletin 457 "Fracture Toughness of Ferritic Steels and ASTM Reference Temperature (To)," describes the results of the three-phase project initiated by the Committee on Failure Modes of Components of the Pressure Vessel Research Council:
1. To verify the Master Curve approach for pressure vessel steels,
2. to develop a database which can be used in the future development of ASME Boiler and Pressure Vessel Code procedures which make use of To or the Master Curve approach and
3. To use the data to develop and verify an ASME Code Case.

A proposed ASME Code Case is presented which uses the current KIc curve, but is shifted using an equivalent reference temperature, which is based on the fracture toughness reference temperature, To, rather than the RTNDT value based on Charpy impact and drop weight test results. Two separate Code Cases based on the proposed draft have been approved by the ASME Boiler and Pressure Vessel Code -- Code Cases N-629 and N-631 for Section XI and Section III applications, respectively.

WRC Bulletin 458 "Application of Master Curve Fracture Toughness Methodology for Ferritic Steels" provides background information and technical arguments in support of using the Master Curve fracture toughness approach to provide an alternative definition of the existing reference temperature (RTNDT) and statistically defined fracture toughness curves for ferritic pressure vessel steels. The origin and bases of the ASME Boiler and Pressure Vessel Code, Sections III and XI, lower bound fracture toughness curves using the RTNDT referencing approach are reviewed and contrasted with the new Master Curve method. The report includes the basis for application of the Master Curve methodology to irradiated pressure vessel steels, as well as the originally intended application to un-irradiated ferritic pressure boundary steels.

WRC Bulletin 459 "Master Curve Strategies for RPV Assessment" describes the application of the Master Curve methodologies by integrating the results using the Master Curve procedure to the existing reactor pressure vessel integrity evaluation methodology. This investigation provides a technical basis for, and empirical support of, use of the Master Curve index temperature (To) as a means to directly measure the adjusted reference temperature for an irradiated RPV steel. The investigation focuses in the following four areas:
1. The technical basis for application of the Master Curve to RPV steels,
2. The bias and accuracy of To values measured using ASTM E1921,
3. Determination of an To-based index temperature (RTTo) for the Kic curve, and
4. A margins strategy for RTTo that matches the intent of Reg. Guide 1.99 Rev. 2 procedures.

Product Details

Published: 2001 Number of Pages: 64 File Size: 1 file , 5.6 MB