Development of high capacity transportable storage cask

Abstract

  Mitsubishi Heavy Industries have developed high performance and reliable transportable storage casks, MSF series casks. The casks have employed newly developed materials that have been expressly developed to obtain long-term stability and quality. Furthermore, the casks have been employed newly designed structure to maximize payload of accommodating fuel assemblies in order to increase economic efficiency of storing spent fuels. The casks have been applied the following technologies.
  Basket assembly of the cask is made of newly developed boronated aluminum. The boronated aluminum is manufactured by powder metallurgy process to provide uniformity of metallic structure and artificial aging which causes deterioration under high temperature condition is not applied to provide the boronated aluminum with high stability for long-term use. For the cask for BWR fuel, simplified basket whose design is that basket consists of some individual squire pipes without assembling is adopted in the cask.
  Neutron shielding material of the cask is made of newly resin of which raw materials have been modified to improve durability.
  Monolithic forging method which is how to shape steel into vessel form is developed to skip welding process between body shell and base plate and to improve reliability.
  Internal face of the body forging is machined to provide “steps” in its cross section in order to fit the external shape of basket assembly and so heat dissipation performance is greatly improved.
  The new technologies have been done demonstration test in order to confirm that MSF series casks satisfy transport regulations.