A summary of the recently completed Phase I of the variety of structural and fracture mechanics techniques. A Project for Fracture Analysis of Large-Scale International 3-d workshop was held in Boston, Massachusetts (U.S.A.), Reference Experiments (Project FALSIRE) is presented, during May 1990, at which 37 participants representing 19 Project FALSIRE was created by the Fracture Assessment organizations presented a total of 39 analyses of the Group (FAG) of Principal Working Group No. 3 of the experiments. The analysis techniques employed by the Organization for Economic Cooperation and participants included engineering and finite-element Development/Nuclear Energy Agency's Committee on the methods, which were combined with JR fracture Safety of Nuclear Installations (CSNI). The CSNI/FAG methodology and the French local approach. For each was formed to evaluate fracture prediction capabilities experiment, analysis results provided estimates of variables currently used in safety assessments of nuclear vessel such as crack growth, crack-mouth-opening displacement, components. Members are from laboratories and research temperature, stress, strain, and applied J and K values. A organizations in Western Europe, Japan, and the United comparative assessment and discussion of the analysis States of America (U.S.A.). To meet its obligations, the results are presented; also, the current status of the entire CSNI/FAG planned Project FALSIRE to assess various results data base is summarized. Generally, these results fracture methodologies through interpretive analyses of highlight the importance of adequately modeling structural selected large-scale fracture experiments. The six behavior of specimens before performing fracture experiments used in Project FALSIRE (performed in the mechanics evaluations. Applications of the various fracture Federal Republic of Germany, Japan, the United Kingdom, methodologies were found to be partially successful in and the U.S.A.) were designed to examine various aspects some cases but not in others. Based on these assessments, of crack growth in reactor pressure vessel (RPV) steels some conclusions concerning predictive capabilities of under pressurized-thermal-shock (PTS) loading conditions, selected ductile fracture methodologies, as applied to RPVs The CSNI/FAG established a common format for subjected to PTS loading, are given, and recommendations comprehensive statements of these experiments, including for future development of fracture methodologies are supporting information and available analysis results, made. Finally, proposals for future work in the context of a These statements formed the basis for evaluations that were Phase II of Project FALSIRE are included. performed by an international group of analysts using a iii NUREG/CR-5997