[en] The transuranic elements such as Np, Am and Cm contained in the spent fuel in nuclear reactors have the long half life longer than several thousands years, and continue to emit alpha particles. The amount of transuranic elements produced in a commercial reactor of 1000 MWe in one year is shown. Also the change of toxicity of the nuclides contained in the spent fuel of commercial reactors is shown as the function of time. At present the method of solidifying high level radioactive wastes with glass and burying them in deep strata is the fundamental concept. However if the transuranic elements having long half life can be converted to the elements having short half life by some method, the burden of their final disposal can be lightened. Japan Atomic Energy Research Institute has carried out the research on the annihilation treatment of transuranic elements using a proton accelerator following the Omega Project of Science and Technology Agency. The research on the development of the proton accelerator used for annihilation treatment, the research on the nuclear and thermal examination of sub-critical system and the basic experiment on nuclear spallation are reported. (K.I.)