Hybrid systems for transuranic waste transmutation in nuclear power reactors: state of the art and future prospects

The features of subcritical hybrid systems (HSs) are discussed in the context of burning up transuranic wastes from the U–Pu nuclear fuel cycle. The advantages of HSs over conventional atomic reactors are considered, and fuel cycle closure alternatives using HSs and fast neutron reactors are comparatively evaluated. The advantages and disadvantages of two HS types with neutron sources (NSs) of widely different natures — nuclear spallation in a heavy target by protons and nuclear fusion in magnetically confined plasma — are discussed in detail. The strengths and weaknesses of HSs are examined, and demand for them for closing the U–Pu nuclear fuel cycle is assessed.