Underground Storage - Hydrogeology: Objectives, Methods, Applications - page 304

have a depth of 1,120 m. The sandstone aquifer is confi ned below a
clay later;
• fi nally, old mining sites can be used.
Demand is constantly increasing, and several projects are under way
in France.
2 STORAGE OF NUCLEAR WASTE
The nuclear energy industry and a few other activities produce waste that
can be harmful for hundreds of thousands of years, and therefore constitutes
a risk for future generations. One of the principal complaints of opponents
to nuclear energy, aside from the ethical problems, is that the cost of waste
treatment and of dismantling abandoned reactors fi nally makes this form
of energy more costly than other options (dams, gas or coal-powered
electric plants). The future of nuclear energy therefore depends on the proof
that the management of waste is possible. The problem of storing these
products is essentially that of long-term contamination of aquifers. The
Chernobyl accident caused a signifi cant contamination, and underground
zeolite dams were put in place on-site, by the AEC, in order to stabilize
the radioactivity.
2.1 Nature of the waste
Waste from the extraction, purification, and enrichment of uranium
contains radon, depleted uranium, and radium. This waste has a long
life, but its radioactive activity is low and the danger, outside of treatment
sites, is therefore limited. Radium can, nevertheless, be taken up by water
and infi ltrated below ground. The problems arise mainly from fi ssion
products. These long-lived products are major actinides (uranium and
plutonium), which, with future technology, may become combustibles
or waste; their future is therefore uncertain. Fission also produces minor
actinides (neptunium, americium, and curium), with no economic value,
and long-lived fi ssion products LLFP, which are defi nitively waste. The stock
of dangerous material is therefore variable, requiring varied solutions. In
France, three classes have been defi ned. Category A waste has low activity
and a short life. It is stored at the surface on sites intended to be operational
for 50 years and monitored for 300 years. The Aube site, with a capacity of
one million m 3 , receives 20,000 m 3 per year. Category B waste has a medium
level of activity but a long life, and fi nally, Category C waste has a high
activity and radiates heat. At the Hague plant, the minor actinides and