Reducing the harmfulness of radioactive waste generated at nuclear power plants and reusing it as a resource is an issue not only in Japan but worldwide.
To solve this problem, long-lived fission products (LLFP) contained in radioactive waste are irradiated with particles generated by an accelerator, and the spallation reaction that occurs there is used to create stable or short-lived nuclei. A method of conversion is being studied.Spallation is a reaction in which protons and neutrons are emitted from the nucleus when high-energy particles are irradiated to the nucleus. It has been suggested that the efficiency of neutrons will improve, and it is attracting attention.

　In conducting a detailed study of the transmutation processing system using deuterons, such as the optimum irradiation conditions, it is necessary to predict in advance what kind of nucleus and how much LLFP will be converted by the spallation reaction by deuterons. It is necessary to keep it.However, deuterons are particles in which protons and neutrons are loosely bonded, and a calculation method that can fully consider the characteristic that they are easily decomposed in the process of reacting with other atomic nuclei has not been established, and the prediction accuracy has not been established so far. It was not high.

　Under these circumstances, in this study, we have developed a calculation method that can strictly consider the effect of deuteron decomposition into protons and neutrons in the spallation reaction by deuterons.When the calculated values ​​were compared with the measured values ​​of the latest spallation reaction experiments, they were in good agreement, demonstrating that the type and amount of nuclei generated from the spallation reaction can be predicted with high accuracy.

　It is expected that this result will greatly advance the research of transmutation processing system using deuteron.

Paper information:[Physical Review C] Role of breakup processes in deuteron-induced spallation reactions at 100–200 MeV / nucleon