Japan has used the G20 meeting to propose setting up an international framework for cooperative research into how to dispose of high-level radioactive waste from nuclear power plants.
The Group of 20 energy and environment ministers are in the town of Karuizawa, Nagano Prefecture, for the second and final day of their meeting.
Japan's industry minister, Hiroshige Seko, chaired a session on energy in the morning. He brought up the idea of the international framework.
He said it is important to share experience and knowhow to accelerate efforts to solve a common issue for countries that use nuclear energy.
Many countries have found it difficult to draw up concrete plans for final waste disposal.
Only Sweden and Finland have decided on disposal sites.
Many nations, including Japan, have not even begun studying potential sites.
The proposal calls for countries to share what they are doing regarding the selection of disposal sites and to promote cooperation and the exchange of human resources.
The first meeting on the framework is planned for October in France.
Ministers are expected to issue a joint statement on Sunday after the conclusion of the G20 meeting.