In order to gain a better nderstanding and acceptance of the task of implementing high level radioactive waste disposal, a study on new communication system about social risk information has been initiated by noticing the rapid expansion of Internet in the society. First, text mining method was introduced to identify the core public interest, examining public comments on the technical report of high level radioactive waste disposal. Then we designed the dialog-mode contents based on the theory of norm activation by Schwartz. Finally, the discussion board was mounted on the web site. By constructing web communication system which includes knowledge base contents, introspective contents, and interactive discussion board, we consucted the experiment for verifying the principles such as that the basic technical knowledge and trust, and social ethics are indispensable in this process to close the perception gap between nuclear specialists and the general public. The participants of the experiment increased their interest in the topics with which they were not familiar and actively posted their opinions on the BBS. The dialog-mode contents were significantly more effective than the knowledge-based contents in promoting introspection that brought people into a greater awareness of problems such as social dilemma.