Machine for installing bentonite buffer blocks for posiva

Posiva tested the installation of bentonite buffer blocks used for final disposal of spent nuclear fuel. Comatec designed a prototype of a special installation machine for the tests. A machine of its kind had never been built anywhere in the world; indeed, designing it was one of Comatec’s biggest product development projects.


  • At the beginning of the design process all that was known was the desired outcome of what the machine would do and the technical requirements involved in that
  • In transporting the blocks it is imperative to keep in mind the susceptibility of the materials, such as bentonite clay, to moisture
  • A target of two hours was set for installation time
  • The simplicity, reliability and installation safety of the prototype were key factors in its design


  • Since only the desired outcome to be achieved by the machine and the technical requirements of that outcome were known at the start of the design process, the concept design stage concentrated on developing different innovative concepts and determining which was best
  • The installation machine fulfils the precision requirements set for storage of spent fuels, thus ensuring long-term safety
  • The operation of the machine is reliable in the demanding conditions of the spent fuel storage site
  • Comatec’s wide-ranging expertise helped create an innovative solution that fulfilled all requirements
"”Working with Comatec has been a smooth process. For example, we have ended up with a completely new solution, so that the bentonite buffer blocks are transported to the installation site in a special transport container”,Keijo Haapala, Posiva"