This bulletin contains three reports on activities of the PVRC working group on application of the Master Curve. Two of the reports contain results of analysis of a set of fracture toughness data from the Japanese KIR Committee and the third report contains the results from an MPC Cooperative testing program on the use of the pre-cracked Charpy size specimens to obtain the reference temperature T0. The Japanese KIR Committee conducted a large-scale fracture toughness testing program for Japanese pressure vessel steels. The fracture toughness data@ which has been analyzed in the first two of these reports@ was developed by this KIR Project. Previous publications of the results from this program concluded that this database is conservatively lower bounded by the existing ASME Boiler and Pressure Vessel Code KIR curve. An alternate KIR curve based on this database was incorporated into ASME Code by Code Case N-610. The objective of these reports is to analyze this database using the new technology in handling fracture toughness@ the Master Curve method. This large data analysis was performed to verify the applicability of the Master Curve method. The results affirm that the reference temperature T0 is the superior indexing parameter for fracture toughness of ferritic steels compared to the currently used RTNDT approach. The results also provide a valuable source for establishing the dynamic fracture toughness and crack arrest fracture toughness data trend. The fracture toughness data@ which has been analyzed in these reports@ was developed by the Japanese KIR Project. The KIR Committee was organized to investigate the effect a 1988 revision to the ASTM Standard E208 would have on the RTNDT temperature used in ASME Sec. III Appendix G. The Reference Temperature@ RTNDT@is determined by a combination of the drop-weight NDT temperature and Charpy impact tests and is used with the Km Curve in the ASME Code for the determination of the fracture toughness of the pressure boundary materials. ASTM Standard E208 is the standard method for the determination of the drop weight NDT temperature. In 1988@ the ASTM revised the procedure for producing the brittle weld on the drop-weight specimen from a two-pass procedure to a one-pass procedure. This change can produce some differences in the measured NDT temperature. A second objective of the committee was to determine if the KIR curve was the appropriate curve for use with modem Japanese pressure vessel steels. Since the Reference Fracture Toughness Curve (KIR Curve) specified in Appendix G to ASME Boiler and Pressure Vessel Code was developed using mainly NDT temperatures obtained by the two-pass method it was felt that a re-evaluation of the KIR curve was needed. The KIR committee was formed to develop and conduct a research program to reevaluate the KIR Curve