High-level waste

During recycling, spent nuclear fuel is immersed in a chemical solution which enables the uranium and plutonium to be separated from the non-reusable residues. These highly radioactive residues make up high-level waste. It represents 3 to 5% of the spent fuel and is composed of fi ssion products (caesium-134 and -137 and strontium-90), activation products (cobalt-60) and minor actinides (curium-244 and americium-241). Because of its high radioactivity, some of this waste gives off heat. Disposal solutions for this type of waste are currently under study.

Treatment and conditioning

High-level waste is stored temporarily in tanks before being calcined in the form of a powder and then incorporated into a molten glass. The mixture is poured into a stainless steel container. The confi nement capacity of this special glass matrix is particularly high and durable. A package of HLW contains around 400 kg of glass for 11 kg of waste. To facilitate future handling, transport, storage and disposal operations, each primary package is due to be placed in a steel disposal container.

Management

As prescribed by article 3 of the June 28th 2006 Planning Act, Andra is developing , as in the case of ILW-LL, a 500-metre deep disposal concept for HLW. The outcome of this study is the commissioning of a repository by 2025 in Meuse/Haute-Marne, subject to government approval and after a public debate.

HLW existing at the end of 2007:

• 0.2% of the total volume of French radioactive waste
• 94.98% of the total radioactivity of French radioactive waste

HLW storage

Pending the commissioning of the deep repository, HLW is stored at production sites, La Hague (AREVA), Marcoule (CEA) and Cadarache (CEA).