The necessity to manage minor actinides (MA), such as neptunium, americium and curium in the spent fuel, becomes more important when mixed oxide (MOX) fuel is used on a large scale in power reactors, both light-water reactors and fast reactors, as more MA will be accumulated in the spent fuel. One way to manage MA is to transmute them in nuclear reactors, such as light-water reactors, fast reactors and accelerator-driven subcritical systems.
The transmutation of MA is, however, not straightforward, as the loading of MA generally affects physics parameters, such as coolant void, Doppler, and burn-up reactivities. In addition, the accuracy of MA nuclear data is not sufficient for detailed design of transmutation systems and for precise prediction of the composition of the spent fuel, because of a lack of measured MA data. Nuclear data of the major actinides, such as U-235, -238 and Pu-239, are based on a vast number of differential and integral experiments, using accelerators, critical facilities and experimental reactors. Integral experiments on MA are much more difficult because of material handling restrictions at facilities, the difficulty of sample preparation, and the necessity to improve measurement techniques to reduce the influence of background radiation. Moreover, most facilities for nuclear data measurements and validation are getting old.
The NSC has therefore decided to establish an Expert Group to critically review integral experiments for validating MA nuclear data, as well as to recommend additional integral experiments needed for validating MA nuclear data and to investigate the possibility to establish an international framework to facilitate integral experiments for MA management.
The Expert Group is expected to work closely with the Working Party on scientific issues of Reactor Systems (WPRS) (WPRS includes the Expert Group on Minor Actinide Burning in Thermal Reactors (MA-ThR), and the International Reactor Physics Benchmark Experiments (IRPhE) Project), the Working Party on Scientific Issues of the Fuel Cycle (WPFC) (the taskforces on comparative study on homogeneous and heterogeneous recycle of TRU and on potential benefits of advanced fuel cycles with P&T, etc.) and the Working Party on International Nuclear Data Evaluation Co-operation (WPEC) (the subgroup on meeting nuclear data needs for advanced reactors (SG31) and the combined use of integral experiments and covariance data (SG33).
The objectives of the Expert Group are to:
Meeting documents and reports are available in the MA working area.
Last updated: 24 January 2012