Feasibility study of large MOX fueled FBR core aimed at the self-consistent nuclear energy system

The potential of a MOX fueled fast breeder reactor (FBR) is evaluated with regard to its ability to transmute radioactive nuclides and its safety when incorporated in the so-called self-consistent nuclear energy system (SCNES ). The FBR's annual production amounts of selected long-lived fission produ cts (LLFPs), Se-79, Tc-99, Pd-107, I-129, Cs-135 and Sm-151, can be transmu ted by using a radial blanket region and a part of a lower axial blanket re gion without any significant impact on its nuclear and safety characteristi cs. The other LLFPs are confined in the system. The hazard index level of t he LLFPs per one ton of spent fuel from the system after 1000 years is as s mall as that of a typical uranium ore. To realize self-controllability (pas sive safety), the proposed FBR core concept employs gas expansion modules a nd sodium plenum above the core. To realize self-terminability, even if MOX fuel melting should cause a core compaction, recriticality of the core can be avoided by a fuel dilution and relocation module. The results show the MOX fueled FBR core has potential applicability to the SCNES. With the fina l goal of the ideal SCNES, fundamental applicability of various coolants an d fuels is evaluated based on neutron balance. It is shown that the harder the core spectra is, the larger the potential for transmuting LLFPs would b e. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.