Page 15 - Demo

using new ligands developed at French commissariat à l’énergie atomique [61]. Americium can also be isolated from the solution using the EXAm process [62] and transmuted separately. This option would be justified as americium is the main long term thermal contributor in vitrified (fission products and minor actinides) waste in a deep repository.
The solution for irradiation reproduces the circulating fluorides solution of a Molten Salt Reactor (MSR) namely: TRU dissolved in LiF-BeF2. It contains, after transmutation, fission products (such as Cs, Sr, I, Zr, Tc, Lanthanides etc.) which is removed with the on-line treatment applied to the fuel of a MSR since they tend to absorb neutrons, but not necessarily proliferate neutrons. Gases such as Xe, I and, to lesser degree, Kr are easily off-gassed from the system.
V. Transmutator wall materials and transmuting medium (FLiBe)
Figure 2 shows the radial build-up of the transmutator consisting of the neutron source as the innermost component, surrounded by a number of concentric cylinder with a concentration of minor actinides to allow to operate in a subcritical environment, the outermost cylindrical shell is reserved for transmuting fission products. The transmutator’s medium between walls is a liquid composed of the LiF-BeF2 (FLiBe) eutectic molten salt which is liquefied by heating to above 350 C. Thus, the walls of the transmutator are exposed to high levels of radiation, corrosion and high temperatures. In this section we describe wall materials, advantages of FLiBe salt, and advantages of the liquid (MSR-like [63]) approach to transmutation.
Wall materials that satisfy the following properties may be considered as a good candidate:
1. Preserve ductility while irradiated by neutron and gamma;
2. Non-corrosive;
3. Resistance to FP creep;
4. Low-Z and thin;
5. Low tritium retention;
6. Easy to manufacture.