Abstract
The discussion on an appropriate level of physical protection has not been elaborated so far because of the confidentiality of its nature, thus resulting in a lack of consensus on this issue. In view of this context, a new system for the evaluation of antisabotage physical protection systems is proposed in this paper, in which we introduce openness to a certain extent in the process of the evaluation. The proposed system is composed of the following three elements; (1) establishment of an evaluation basis threat (EBT), which should be less strong but more likely to occur than the design basis threat (DBT); (2) employment of realistic standard scenarios in the process of evaluation; (3) disclosure of results of evaluation implemented based on the above EBT and standard scenarios. It is expected that this considerably open system will foment peace of mind among citizens as well as create a deterrent effect that would minimize the occurrence of sabotage on nuclear facilities.