South African expertise has played a key role in the development programme for France’s world-leading project to create a permanent high-level nuclear waste repository (HLNWR). This is the Cigéo project, Cigéo being the French acronym for Industrial Centre for Geological Disposal. It is being implemented by France’s National Radioactive Waste Management Agency, better known by its French acronym, Andra. Originally set up in 1979 as an agency of the country’s Atomic Energy Commission, it was established as an independent public body at the end of 1991.

The Cigéo HLNWR will store high- and intermediate level nuclear waste underground in a stable geological formation. It will be located in north-east France, some 300 km east of Paris, on the border of the Haute-Marne and Meuse departments (provinces) and is expected to cost at least €25-billion. Detailed design is programmed to finish in 2017 and it is scheduled to be commissioned in 2025, after decades of research, technology development, testing and public consultation. This process started in 1991, with the licensing of the Underground Research Laboratory at Bure, in the Meuse department, which was completed in 2006. This was followed by the construction of the Technological Exhibition Facility (abbreviated to ETe in French) nearby, at Saudron, in Haut-Marne. The ETe is a technology development and demonstration facility, a precursor to the full-scale HLNWR.

In 2002, during the construction of the Underground Research Laboratory, a tragic accident during shaft sinking killed a worker and the French decided they needed help from those they regarded as the best shaft sinkers in the world – South Africans. ARINT SA MD François Mellet was contracted by Andra because he had considerable expertise in the nuclear sector (having worked at Koeberg for many years), to which he had subsequently added experience in mining and because he could speak French (having received nuclear training in France). The shaft sinking opera- tion was taken over by the South African team of engineers and shaft sinkers and successfully carried out.

The laboratory is situated in a 150-million-year-old basin of Argilite (sedimentary rocks formed mainly from clays), at a depth of some 500 m. “The shafts are too narrow to move [nuclear] waste down them, to reassure critics and locals that it really was just a research project,” he told last month’s Nuclear Africa 2016 conference. Two shafts were sunk and subsequently joined by a tunnel. “It is the most advanced underground research laboratory in the world,” he highlighted. There are now 1 600 m of tunnels and galleries, used for various experiments, including surveys of the surrounding Argilite. All the required scien- tific research has been fully funded. It has already been determined that the rock has not moved at all in 20-million years. “You don’t even see cracks!” reported Mellet. Currently, thermal experiments are being conducted, in order to determine the effect on the surrounding Argilite of relatively hot (90 °C) radioactive waste.

Strikingly, the public consultation process was conducted entirely online. This was because attempts to hold public meetings were disrupted by protesters. “The online system worked very well,” he affirmed. “The results were impressive. There has been strong local consultation and parti- cipation.” The French authorities are also busy bringing the necessary laws, regulations and technical requirements into line with each other. The project is completely open, and confidentiality will be imposed only on the final design, in order to prevent unauthorised copying. “They’re going to have the best, I can assure you.”

The Cigéo HLNWR will receive high-level nuclear waste for 150 years. It will have two surface sites and two 5 000-m-long inclines, down which the waste will be taken, for storing in side tunnels and galleries. There will be a continuous process of boring new tunnels and galleries, to create more space as the early excavations are filled up and sealed. The waste will be held in nondeformable concrete or steel containers.

An interesting complication is that the waste must be retrievable over a period of 100 years. This is to allow for the possible development of new technologies that might permit the further reprocessing of the waste (so reducing its quantity) or even consume the waste entirely. Should retrieval of the waste be required, it would be carried out by robots.