COMPLETE DOCUMENT (1862 kb) - OECD Nuclear Energy Agency

The SPIN programme studied various technical methods aimed at modifying the composition
of the wastes:
• the PURETEX programme for medium-active waste: the main goals are a best recovery of
the plutonium, and waste volume reduction ;
• the ACTINEX programme for highly-active waste: this programme concerns partitioning
and transmutation of, on one hand, minor actinides (which are the main contributors to the
long-term radiotoxic inventory of such waste), and, on the other hand, some long-lived
fission products (which are to be considered, owing to their relative greater potential
mobility under storage or geological disposal conditions ).
The main results obtained can be summarised as follows:
• a very significant reduction of the amount of medium-active waste has revealed feasible
and been achieved by COGEMA at industrial scale in “La Hague” plants since their
commissioning; hulls remain bulk contaminated by long-lived elements, prohibiting their
surface storage;
• the PUREX process already separates U, Pu and I and could perhaps be extended to Zr,
Tc and Np. Further research requiring complementary extraction steps, is needed for the
separation of Am, Cm, Cs and of other long-lived fission products;
• the transmutation of MAs is feasible in fission reactors (critical or subcritical), in
particular if fast neutron spectra are envisaged. The transmutation of long-lived fission
products needs a relevant neutron excess, in particular if elements (and not isotopes) are
considered for transmutation. Different modes of recycling can be envisaged (homogenous
and heterogeneous). In the case of Am, a “once-through” irradiation of targets in
moderated subassemblies is an option, which is presently under study. However, the
combined management of Am and Cm could lead to reduce more significantly the source
of potential radiotoxicity. Several options are examined in this respect:
− separation of Cm, to be let to decay in a specific installation, in order to recover the
resulting Pu, to be further recycled;
− “once-through” irradiation of Am + Cm targets, with the objective of > 95 %
cumulative fission (irradiation length > 20 years);
− use of dedicated reactors, to be fuelled with some appropriate mixture of Am + Cm
(and eventually some Pu); safety considerations (e.g. low β eff with critical
configurations) lead to the evaluation of ADS.
R&D activities are performed today in all these fields in particular in basic chemistry
(thermodynamics ; molecular modelling …) and physics (e.g. nuclear data), and in more applied fields:
separation processes design and hot tests in the ATALANTE facility; core concepts experimental
validation, fuel studies … A significant irradiation programme has been drawn up, mostly performed or
to be performed in Phénix, but also in the frame of collaborations (e.g. the European collaboration
EFTTRA; collaboration with the Russian RIAR Institute at Dimitrovgrad, etc). As far as ADS, R&D
activities are performed for the experimental subcritical neutronics validation, in the intense accelerator
development field and in the material studies (related to the window and target). These activities are
performed by CEA in close co-operation with the French National Research Institute CNRS, in the
frame of a joint programme (GEDEON).
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