TND requirements for alternate fuel cycles

A review is given of recent developments in alternate fuel cycle studies, with emphasis given to those studies having a possible impact on requirements for data on transactinium nuclei. These include extended burnup in LWR's, the use of thorium to supplement the use of uranium, the use of accelerators to produce fissile material, and the Fast Mixed Spectrum Reactor. The new features introduced by these concepts are longer burnup of fuel, and hard neutron spectra in breeders. Similar trends appear in studies of transmutation of nuclear waste, where a new feature is the possibility of recycling actinides in LSR fuel which has not undergone full fuel reprocessing but has been treated by the Airox process. Such recycle in thermal reactors would lead to generating large amounts of higher transactinide nuclei. The concepts that depend on extended burnup do not lead to new requirements for data on transactinide nuclei, but they do strengthen the requirements that have been stated in the past. Among the requirements for data for the hard spectrum breeder, the need for measurements of capture cross-sections of transactinides above a few hundred keV is most important. Requirements also exist for (n, Nn) cross-sections. (author)