Overview of activities related to the WGCS/AG2 in the study of structural analysis methods and damage models for the development of design rules

For about twenty years the WGCS has been in existence as a standing group of experts whose activities were devoted to examine mainly preharmonization topics and matters related to the integrity of FBR (Fast Breeder Reactors), for mechanical components relevant to nuclear safety. A large portion of the studies produced by the Group, exhibited a common interest for both FBR and LWR (Light Water Reactors) in the framework of the pre-standardization of codes and standards used for design, construction and operation of NPPs mechanical components. Since 1991 the WGCS has implemented specific LWR - annual programmes in addition to annual FBR programmes. In fact, the WGCS seeks, inter alia, to promote studies and development activities for clarification and building of consensus at community level concerning technical issues of relevance in the preparation of European technical codes and standards, should the need for them arise. Accordingly, the group is orientated to: identify and update information relative to existing safety significant codes, standards and requirements related to design, manufacturing, materials and inspection activities; define points of similarity and analyze problems induced by discrepancies; define fields for which additional data and analyses are required, and contribute to fill such gaps encouraging appropriate studies and development activities. The WGCS involves EU experts from electrical utilities, NSSS vendors, engineering companies, laboratories and nuclear safety support organizations with specific interests in the nuclear field. Although prestandardization activities of the WGCS have been directed towards codes and standards, the group is neither involved nor associated with the drafting process of codes and standards, the latter process falls into the scope of International and National standardization bodies whose information is being considered by the WGCS in a selective manner regarding their impact on nuclear safety. Incidentally, two other areas, one related to Research and Development programmes the other to and industrial projects conducted by EU organizations, have been an important source of input to the WGCS work. Therefore, it could be mentioned that the work produced by the WGCS moves amongst the three boundary areas described above. Paper describes the outstanding studies and ongoing activities of the WGCS including simplified calculation methods and established computational techniques as well as constitutive equations needed for complicated material descriptions and benchmarks