NEA experts found the final disposition method chosen by SKB to take care of Swedish nuclear fuel, known as KBS-3, to be suitable. The choice of Forsmark as a final disposition spot was also approved, as was the choice of copper capsules to enclose the radioactive waste.
But the experts still considered several important points unclear.
“We’ve pointed at some uncertainties in the models used by SKB to describe how the groundwater moves in the mountain. The uncertainty analyses must be improved on that point,” said the group’s chairman, Michael Sailer.
Sailer is a researcher at Öko-Institut eV, in German Darmstadt.
The NEA’s experts aren’t entirely satisfied with the criteria SKB used to choose suitable spots for the holes in which the copper capsules will be placed, considering the mountain’s cracks and irregularities.
“There aren’t any clear criteria for this in the documentation presented by SKB,” said Sailer.
SKB’s methods for assuring the quality of the technology and production methods needed for the construction of the final disposal were also deemed unclear by the NEA.
The group also pointed out that some questions about the possibility of the copper capsules rusting must be resolved.
This issue has been the cause of much debate among Swedish researchers. The Royal Institute of Technology consider that copper can corrode in an oxygen-free environment, but SKB claim the opposite.
On Friday, the Swedish Radiation Safety Authority (Strålsäkerhetsmyndigheten – SSM) finished their stress test of Swedish nuclear power plants, concluding that the plants are robust and resistant.
However, in the event of several reactors being knocked out simultaneously for a longer period of time, more electric power is needed, as well as long-term water cooling systems for the core, concluded SSM.