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Workers wear safety clothing to deal with nuclear waste

Or we have no chemistry with nuclear power; the management of its waste arises in the same terms, often long. The solution of land filling is its hole.
Talk about a hole? The well-maintained road shivering through a bleak undulating dusted with snow. Benumbed by groves morning freeze emerge from the fog. We wear safety clothing leave the Haute-Marne to the Meuse’s harsh hundred souls, is not far? the hole, either.

A network of tunnels that run 490 meters underground for which ANDRA (National Agency for Radioactive Waste Management) never ceases to move heaven and earth, with some success of greater economic output outlook, scientific experimentation collateral-size and surface facilities erased Cage the project (industrial center of geological storage) is poised to establish itself permanently in this disinherited landscape.

The site is quiet, not secret. “The 30,000 m 3 excavated to dig 1,200 meters of galleries are negligible compared to the volumes resulting from the operation of a mine, gelatinized Jacques Delay, chief scientist of the 1999 site at 2010. This is the deviation of the ramble the city of Joinville nearby. And these experimental galleries can be visited. For safety reasons, including evacuation, the number of people is limited to 49, including staff, so it is never more than six visitors at a time. ”

No hanging of the room, but a lamp store where waiting patiently the happy faces of the lucky ones who will not stay on the floor. We put on the dress of Brue: helmet, front, reflective vest, relocation and device Apia belt.

The elevator snorts. After eight minutes of a descent rocked by the metal grating of cables, the cage opens on a network of animated galleries where pedestrians are not a priority. The air from the bottom is as fresh or nearly the bottom surface air: “The natural rock temperature is 23.2 °. The ventilation system lowers it to 15 in winter. ”

“The outside temperature in contact with the rock of nuclear high-level waste continues hydro geologist, is 90 °, which corresponds to the temperature transducers produced by a waste package generating a thermal power of 500 watts. The decay curve is known. Past 90 °, the vapor phase is predominant. If the model becomes more complex, the properties of clay which does not change after 140 ° leave the margin. Its conductivity is much lower than that of granite. ”

His hand touches the grayish rock “His 35 to 45% clay, 30 to 40% limestone, 20% silica (sand), 1 to 2% pyrite and 1 to 3% of organic materials are the product of a deep sea and old of 165 million years. The sedimentary rocks of all geological periods have compacted. ”

If it has not solemn nobility of marble, argillite offers guarantees of perpetual concession deemed inviolable: “Nuclear waste, in 2025, will be buried 490 meters underground, in the heart of a layer located between 422 and 552 m. Characterized by its fine particle size and homogeneity, this rock surprised by its elasticity and plasticity. It is this deformation is measured. Pressure 500 m rock above our heads is 12.7 MPA, of the order of that which is exerted on the hull of a submarine at 1,200 / 1,300 m.”

Natural bandage
Instinctively, his eyes alight on the supporting posts. “The sliding hangers have closed 20 cm from the opening. Most of the deformation took place in the first fortnight. This elastic deformation followed by plastic deformation. Deferred, this creep is not reversible. The oldest galleries, aged ten, are closing today at the rate of 0.1 mm per month. The galleries are to study the maxima and minima of the horizontal thrust of the training.”

It takes granules in a bucket “Betonies is clay which swells in humidity. Natural, after saturation impermeable, resistant to pressure, that is a sealing device which ensures at the same time stabilizing and healing the rock damaged by the excavation.” said Mache in reflective clothing. It is at the end of the tunnel. It was in the air, contaminated with the certainties of our guide.

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