Current plants in Japan are licensed against Japanese regulatory standards, codes and guidelines. The Japanese approach to safety is harmonised with other international activities through participation in IAEA activities. For example, Japanese utilities participate in the US ALWR initiatives.

The requirements for future ALWRs are being established by both regulator and utilities. In parallel, design programmes for future plants are proceeding with improved safety levels. Current Japanese plants such as the APWR and ABWR have core melt frequencies below 1E-6/reactor year, below the International Nuclear Safety Advisory Group (INSAG)-3 target for future plants of 10E-5/reactor year.