What's NUMO?

The Nuclear Waste Management Organization of Japan (NUMO) is engaged in the mission of implementing safe geological disposal of radioactive waste.

NUMO was established in October 2000 in accordance with the Designated Radioactive Waste Final Disposal Act, authorized by the Ministry of Economy, Trade and Industry (METI). NUMO is tasked with implementing final disposal -geological disposal- of high-level radioactive waste (HLW) and low-level radioactive waste containing long-lived nuclides (TRU waste) from Japanese nuclear fuel cycle.

Radioactive wastes for geological disposal

The spent fuel from nuclear power generation can be reused by reprocessing. After reprocessing, high-level radioactive waste (HLW) and low-level radioactive waste containing long-lived nuclides (TRU: Transuranic waste) are also generated as by-products and require safe management.

The reprocessing of spent fuel is used to separate re-usable uranium and plutonium from the waste. The resulting liquid containing high-level radioactive waste will be vitrified in a stainless steel container. This is called high-level radioactive waste (HLW) or vitrified waste. Additionally, different kinds of low-level radioactive wastes are generated in the reprocessing facility. NUMO is responsible for safe management of HLW and TRU waste which includes long-lived nuclides by implementing geological disposal.

Geological disposal

In the geological disposal, radioactive waste will be emplaced in the stable deep underground deeper than 300 meters for long-term isolation of the waste from people and the environment.

Various disposal methods were studied to isolate the radioactive waste from people and the environment for a period of time extending over tens of thousands of years. The geological disposal is internationally recognized as a common concept for effective waste isolation by using natural capability of confining material in deep geological formations. Among international communities, Finland and Sweden have decided sites for geological disposal.