|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||||||||||||||||
|
____________________________________________________________
The SAFIR 2 report was limited to scientific and technical aspects. It evaluated confidence in the safety, feasibility and the soundness of the disposal system studied. However, a long-term radioactive waste management solution must not only be safe and technically feasible, it must also be acceptable to society and ONDRAF/NIRAS was particularly conscious that even if a solution were scientifically correct, it could not go ahead without political consensus and social acceptance. In the case of category A waste, this is the reason why the deep disposal solution and the way in which this waste will be disposed of are being discussed by local partnerships. In the case
of category B and C waste, it is ONDRAF/NIRAS's opinion that social dialogue
between all concerned should be encouraged to the full. This is why, in
coming years, the ONDRAF/NIRAS Research & Development programme will
try to re-establish equality between the technico-scientific and societal
dimensions. In concrete terms, this means that the participation of society
will take the form of real dialogue which is open to all parties involved.
Indeed, a decision-making process must be put in place that is capable
of responding to society's expectations. Clearly, ONDRAF/NIRAS, will have
to establish structures representing society as a whole that will be in
a position to influence the continuation of the Research & Development
programme.
____________________________________________________________________________ In order for the radioactivity contained in the waste to reduce without harming man or the environment, the disposal solution must provide optimum protection in accordance with the principle of multiple safety function. This principle consists in using a series of successive and complementary barriers each with its own function within the scope of the long-term safety of the repository (impermeability, corrosion resistance, dissolution, solubility, retention, diffusion, leaching, etc.). The various natural or man-made barriers must, each in their own way, contain the radioactive substances and slow their migration in the long term. The barriers
will be selected and designed in such a way that the overall performance
of the disposal system does not depend on any single barrier alone. This
ensures that even in the event a barrier did not function entirely as
intended (because of unexpected or unlikely events), a sufficient safety
margin would still be guaranteed.
______________________________________________________________________________
Deep disposal
is being considered for the three categories of waste. While the overall
repository architecture is identical for all classes of waste, certain
barriers would differ depending on the class of waste to be disposed of.
The principle of multiple safety function also applies to a deep disposal.
Which are the different barriers for category C waste? The repository here also takes the form of a network of underground concrete galleries (4) in which the "supercontainers" are buried. When all the galleries are full, the repository is entirely closed off with backfilling material and plugs. The repository infrastructure is thereby completely isolated from the outside world. The main barrier on which the safety of the repository rests here again is the geological layer in which this facility could be constructed, i.e. a layer of poorly indurated clay. This barrier is the most important as it is the one that has to slow the migration of radionuclides towards the biosphere for a sufficiently long time when the man-made barriers are no longer effective (i.e. after the thermal phase). So it is the site's geology that must ensure that the long-term radiological impact of the waste in the repository stays below the nationally and internationally (IAEA) allowable limits and is therefore significantly lower than natural radioactivity. Indeed, the lasting quality of the man-made barriers cannot be guaranteed over the extremely long periods of time to be taken into account (several tens or even hundreds of thousands of years).
____________________________________________________________ The SCK·CEN (Belgian Nuclear Research Centre) began research in 1974 to determine whether radioactive waste can be buried in Boom clay and an underground research laboratory named HADES was set up (at a depth of over 200 meters) in the early 80s to study this clay as a potential host formation. Since its creation in 1980, ONDRAF/NIRAS has managed and coordinated the Belgian Research & Development programme in close collaboration with the SCK·CEN and with financial support from the European Commission. In 1995, this collaboration led to the creation of an Economic Interest Group known as EIG PRACLAY. In 2000, EIG PRACLAY was renamed EIG EURIDICE. The Belgian
Research & Development programme is a methodological programme dedicated
to determining whether it is technically and economically possible to
come up with a safe solution for the deep geological disposal of radioactive
waste. This programme, which is necessarily multidisciplinary and progressive,
can be divided into three phases: _______________________________________________________________________________ If you don't understand a term, please refer to our glossary.
|
|||||||||||||||||||
.gif){kind=small}
