In the EU and the USA, Safety Analysis Report (SAR) is made as a comprehensive document concerning plant safety, which covers the areas of design, construction, operation, maintenance as well as safety related activities (quality insurance, safety culture etc.) at the construction stage in the beginning. This document is maintained in the state of "as-is" with added modification during operation, and used as a significant tool to control the plant safety. On the other hand, Japanese plants currently have not had such a scheme to check comprehensively the safety of the plant and to maintain its report, so there are issues whether in a timely manner they have assessed the safety level and taken proper measures, and have been sufficiently accountable for the safety to public. JANSI is developing the guideline for Japanese Safety Assessment Report (JSAR) to voluntarily check the plant safety comprehensively and periodically. The development follows international standards such as R.G.1.206 (Guide for Combined license applications for nuclear power plants) of NRC as well as Japanese regulatory requirements. JSAR will have two stages. The first one is the USA type SAR, and the second one is the EU type PSR JSAR is expected to contribute the enhancement of Japanese plant safety. This development could cause the following expected results: √ Confirm the latest safety level and conduct effective measures in a timely manner √ Enhance the competency of plant personnel √ Sufficiently accountable to public and foreign countries √ Streamline the regulatory process in the future