PSI Investigates For Suitable Swiss Deep Geological Repository
Switzerland is planning to construct a deep geological repository for its radioactive waste by 2050.
Three sites are currently under consideration and researchers at Paul Scherrer Institute are providing data that will help in determining which is most suitable.
The search for suitable locations is being conducted according to the Sectoral Plan for Deep Geological Repositories.
Switzerland is currently in Stage 3, in which drill core samples are analysed to determine which of the three candidate sites (Zürich Nordost, Jura Ost, or Nördlich Lägern) is best.
According to Andreas Pautz, professor for nuclear technology and head of the Nuclear Energy and Safety Division at PSI, Switzerland is fortunate to have Opalinus Clay as a suitable host rock, so “a deep geological repository is therefore technologically feasible and an extremely safe solution”.
Indeed, Opalinus Clay, formed 173 million years ago when a shallow sea covered northern Switzerland, acts as a natural containment barrier for water, slowing down the migration of radionuclides.
Being the rock virtually impermeable, if water does penetrate the clay, it swells and fills the entire space available. This is the so-called self-sealing property of clays.
Moreover, positively charged radionuclides readily attach themselves to the negatively charged surface of the clay particles and form chemical bonds.
“In a sense, one could imagine that Opalinus Clay acts like a magnet” said Sergey Churakov, head of the Laboratory for Waste Management at PSI.
Ready the full story: Safely stored for a million years – Paul Scherrer Institute