Research groups at Tokyo Institute of Technology, Tohoku University, Tokyo City University, and Japan Atomic Energy Agency have converted long-lived fission products contained in radioactive waste generated from nuclear power plants into short-lived nuclear species and are harmless. I proposed a system to change.
The system proposed in this study excludes tin, which is low in production and extremely low in neutron reactivity, from the seven nuclides (commonly known as LLFP) with particularly long half-lives among the fission products contained in spent nuclear fuel. Converts 7 nuclides to short half-lives (or stable nuclides) at the same time.LLFP and a newly proposed moderator are placed around the core of a small fast reactor to absorb neutrons, and the isotope composition emitted from the fast reactor remains the same (that is, additional processing such as isotope separation is performed). It is said that the effective half-life can be dramatically reduced compared to the physical half-life, and more LLFP can be converted into harmless nuclides than the amount produced in the core of a fast reactor.
In the fast reactor of the present proposal, plutonium generated and accumulated in the conventional light water reactor will be used as fuel.In the future, plutonium emitted from dismantled nuclear weapons generated by nuclear disarmament can be effectively used, which can contribute to nuclear non-proliferation.It is possible to perform these at the same time as the original purpose of power generation in the fast reactor, and further reduce the risk of environmental load at the geological disposal site.
With this transmutation system, it is expected that the total amount of LLFP in the spent nuclear fuel accumulated in Japan can be processed by about 10 small fast reactors.A new method for effectively utilizing the "Monju" class small fast reactor, which has already been constructed, as a device that can contribute to the reduction of radioactive waste volume and nuclear non-proliferation has been clarified, and it is expected that the burden on future generations will be reduced.
Paper information:[Scientific Reports] Method to Reduce Long-lived Fission Products by Nuclear Transmutations with Fast Spectrum Reactors
