[en] This paper provides an overview of the activities of the Principal Working Group No. 3 of CSNI, the Fracture Assessment Group (FAG) which was given the task of reviewing work on fracture assessment methods as they relate to safety concerns in the nuclear industry. It provides an overview of project FALSIRE which was a coordinated program to assess a limited number of large scale reactor component tests. The tests were conducted under pressurized thermal shock conditions, such as might occur as a consequence of a LOCA in a reactor. The objective was to get detailed analyses on these experiments, to aid in the development of analytic capabilities, while avoiding the duplication of experimental efforts about the world community. The committee has also documented other large scale experiments beyond those included in the FALSIRE project, as well as experiments on reactor pressure vessel response to such thermal shock loading conditions. On the basis of information collected to this point the committee has suggestions related to further data needs on the part of this program. These are both experimental and analytic. 20 figs., 5 tabs