What should be done with radioactive waste? At present, only the solution of very long-term underground storage is envisaged. The 7:30 p.m. went to France in the laboratory of Bure, in the Meuse (north-east), where one studies the conditions of such storage.
It is undoubtedly one of the most strategic sites in the country. More than 500 meters deep, an elevator leads to where the most radioactive waste is stored. Such a depth is necessary to reach a layer of clay that dates back 160 million years, a rock that must serve as a safe.
“This is a prerequisite for storage. This is what will allow it for thousands of future years to be unaffected by surface phenomena, climate change or even erosion. Mineralogy, a constitution of minerals, is also favorable for retaining radioactive elements”, explains Emilia Huret, head of the Meuse-Haute-Marne center of the National Agency for the management of radioactive waste.
The nuclear waste buried on this site can remain highly radioactive for several tens of thousands of years.
83’000 m3 waste to store
In all, France must store 83,000 m3 of long-term waste, the equivalent of 29 Olympic swimming pools. This waste, which comes, among other things, from the combustible ashes of the power stations, will be placed in steel cells, the resistance of which is tested by the laboratory.
“Here, we measure the temperature or the deformations. This type of cell will also measure the evolution of the gases it contains”, specifies Emilia Huret.
Leaks to check
If the waste will be wrapped in layers of concrete or steel, scientists already know that the protections will crack over time and release radioelements. The essence of the work of the French laboratory is therefore to simulate such leaks in the rock.
“Today, we know that this rock is capable of confining radioelements for several hundred thousand years. For example, the most radioactive elements will only come out of the layer after 100,000 years”, explains Emilia Huret.
The most important thing is that this storage be known to future generations. An immense work of reflection must therefore be done on the transmission of information for the future.
“What writing, what language are we going to use to transmit information for as long as possible, knowing that the nuclear safety authority is asking us to ensure transmission of memory for at least 500 years?” Asks Audrey Guillemenet , communication officer for the underground laboratory.