Burnup credit implementation in WWER-440 dual purpose cask

Based on worldwide research community consensus related to the framework of the burnup credit (BUC) implementation methodology, a transfer of the latest state-of-the-art knowledge to the WWER-440 application environment initiated and encouraged national research and development on this topic in the Czech Republic. The project entitled the 'Development of Technology Related to Burnup Credit Implementation in Storage and Transport Spent Fuel Casks' was proposed; this has been in development since late 1999 and comes to completion this year. Two collaborators, the Nuclear Research Institute (NRI) at Rez and SKODA JS company in Plzen, the Czech Republic, were developing a WWER spent fuel dual-purpose cask design based on the burnup credit implementation. The SKODA JS company, which is the only WWER spent fuel cask and component manufacturer in the Czech Republic, has only produced dual-purpose casks of the classical design so far. In this newly proposed design, the enormously conservative reactivity margin, which is connected with the spent fuel burnup, was converted into a cask material and capacity improvement due to the BUC implementation, keeping approximately the same price of the cask at the same time. Original design features enabled the designers to overcome difficulties connected with the heat transfer and removal solution as well as to meet the standards put on the transport casks. (author)