Container for Czech spent nuclear fuel repository is ready

Škoda JS has announced that it has completed the development of a geological disposal container (technically known as a disposal package) for storing spent nuclear fuel in a future deep geological repository. The hermetically sealed container for highly radioactive fuel assemblies from VVER reactors is made of stainless steel.

Škoda said that under its disposal concept, spent fuel assemblies are placed in sealed, thick-walled stainless-steel canisters, which are housed inside a carbon-steel cylinder sealed at both ends.

Hundreds of thousands of years without loss of hermetic sealing

"As part of the project, an optimal design solution for the disposal package was developed and, based on corrosion tests in a simulated environment of the future repository, highly corrosion-resistant materials were also identified that will ensure the storage of spent fuel for hundreds of thousands of years without compromising the hermetic sealing of the disposal package," the company said.

The material's corrosion resistance was tested in cooperation with the ÚJV Řež research centre, the University of Chemistry and Technology in Prague and ENERGOVÝZKUM Brno.

The same disposal concept works for both types of fuel assemblies. The company said that the casks for fuel from the Dukovany reactors are 4 metres high and weigh 14 tonnes. The Temelín container will be 5 metres long and weigh 18 tonnes.

The Dukovany container can hold 7 VVER-440 fuel assemblies, while the Temelín container can accommodate only three VVER-1000 fuel clusters. Both types of cask have a diameter of 914 millimetres, so the handling, transport and welding procedures are the same. Closure welds will be carried out using welding robots inside hot cells.

Smaller prototype ready for visitor centre

Both Czech nuclear power plants, Dukovany and Temelín, have a total of six reactor units, accounting for approximately one-third of the country's electricity production.

Škoda JS manufactured a prototype cask as part of the design verification. It was somewhat shorter and includes cutaways so that it can later become an exhibit at the future visitor centre of SÚRAO, the Czech Radioactive Waste Repository Authority, which is responsible for building the deep geological repository in Czechia where the aforementioned casks will be disposed of.