Design considerations for CDA accommodations

This paper presents a view on the safety design approach among Japanese FBR community focusing on the CDA (core disruptive accident) accommodations, which can be summarized as follows: 1) CDA is classified as beyond design basis accidents; 2) emphasis is placed on the harmonization of prevention and mitigation of the accidents; 3) CDA is to be accommodated in the reactor vessel by the conventional design method taking into maximum account of self-limiting intrinsic mechanisms of the phenomena. To attain the in-vessel retention of CDA consequences, generic and effective measures are suggested in light of the recent increased understanding of the physics. (author)