This chapter examines the technology of innovative accelerator driven systems (ADS). ADS are possible candidates for a range of applications; importantly, they provide a means of separating and eliminating actinides by a process referred to as partitioning and transmutation. They can transmute long-lived radioisotopes into short-lived or even non-radioactive isotopes, using an excess of neutrons available from a fission chain reaction. These neutrons are generated in a hybrid sub-critical reactor accelerator system, which forms the basis of the ADS. In such a system, high-energy protons produced by an accelerator bombard a 'target', producing an intense neutron source; this part of the process is termed 'spallation'. These neutrons are multiplied up in a sub-critical reactor, referred to as the 'blanket', which surrounds the spallation target. Thus, an important application for ADS technology could be to transmute high-level nuclear waste to non-radioactive materials or materials with much shorter half-lives. The issue of highly radioactive waste produced from reactor operation is a continuing problem with regard to the future of nuclear power.

Accelerator Driven Systems

An accelerator‐driven fast reactor (700 MWt), run in a subcritical condition, and fueled with MOX can generate 233U more safely and efficiently than can a critical reactor. We evaluate the production of 233U, 239Pu, and the transmutation of the long‐lived fission products of 99Tc and 129I, which are loaded with YH1.7 between the fast core and blanket, by reducing the conversion factor of Pu to 233U. And we assessed the rates of radiation damage, hydrogen production, and helium production in a target window and in the surrounding vessel.

Hiroshi Takahashi

Papers

Transmutation of high‐level radioactive waste and production of 233U using an accelerator‐driven reactor