Development of System Based Code for Structural Integrity of FBRS

Abstract

This paper introduces a newly started study that aims to expand the basic concept of the system based code for structural integrity, which has been proposed by Asada et al [1,2], for application to fast breeder reactors (FBRs) [3]. The System Based Code for FBR (FBR System Based Code) offers more reasonable structural integrity assessment methods for relatively important components of FBR than current codes and standards do, to enable profound improvement both in reliability and lifetime cost-effectiveness. It will be realized by margin optimization through an integrated evaluation of all the technical fields that affect structural integrity at the stage of design. Those fields are the prerequisites of design, material, design analysis, fabrication and installation, preservice inspection, operation, inservice inspection, and repair and replacement. For margin optimization, three promising methods, failure probability assessment, application of quality assurance index, and the introduction of “systematized design factors” were proposed. The FBR System Based Code will consist of a control code and partial codes. The former takes care of margin optimization while the latter offers various options of technologies and engineering tools among which a designer can chose the most appropriate one according to various requirements to be fulfilled. Partial codes will be developed for each technical field that is dealt with in the code. Technologies that need to be developed for the development of the FBR system Based code were also clarified.