Head-end reprocessing studies
The fuel used in current nuclear reactors consists of uranium oxide or a blend of mixed uranium and plutonium oxides. After its use in the nuclear reactor the fuel still contains a substantial amount of recoverable materials. The partitioning (separation) of minor actinides and fission products from spent fuel and the later re-use in a nuclear reactor are crucial components of a closed nuclear fuel cycle.
by thermal and thermochemical treatment of fuels
The main topic of the Head-end reprocessing studies by thermal and thermochemical treatment of fuels project (HERACLES) is the partitioning of fission products from spent nuclear fuel by thermal treatment as a possible head-end step of advanced reprocessing flow-sheets (either hydrometallurgy, e.g. PUREX process, or dry reprocessing techniques).
The project consists of two main parts:
- Experimental investigation of the head-end removal of actinides and fission products by thermal and thermochemical fuel treatment (influence of temperature, oxidizing or reducing conditions etc), development of new analytical techniques for online monitoring of the element separations
- Support of the experimental program by theoretical calculations of FP speciation (thermodynamics) in the irradiated fuel and kinetics of FP release more
- Fundamental study of thermodynamics and kinetics of FPs in the complex multicomponent systems (that is typical for irradiated nuclear fuel)
- Improvements in extraction flow sheets indicating the best operating conditions for actinide and fission product separation for a pilot scale facility
- Better understanding of chemical behavior of volatile and semivolatile species in fuel samples under normal and abnormal conditions