Castor® and Constor® Type Transport and Storage Casks for Spent Fuel and High Active Waste

Abstract

The German company GNB has developed, tested, licensed, fabricated and loaded a large number of casks for spent fuel and high-level waste. CASTOR® casks are used at 18 sites on three continents. Spent fuel assemblies of PWR, BWR, WER, RBMK, MTR and THTR types as well as vitrified high active waste (HAW) containers are stored in these kinds of cask. More than 600 CASTOR® casks have been loaded for long-term storage. Two decades of storage have shown that the basic requirements, which are safe confinement, criticality safety, sufficient shielding and appropriate heat transfer, have been fulfilled in each case. There is no indication that problems will arise in the future. Of course, the experience of 20 years has resulted in improvements in the cask design. One basic improvement is GNB's development since the mid 1990s of a sandwich cask design using heavy concrete and steel as the basic materials, for economic and technical reasons. This CONSTOR® cask concept also fulfils all design criteria for transport and storage given by the IAEA recommendations and national authorities. By May 2002 40 CONSTOR® casks had been delivered and 15 had been successfully loaded and stored. In this paper the different types of casks are presented. Experience gained during the large number of cask loadings and more than 4000 cask-years of storage will be summarized. The presentation of recent and future developments shows the potential of the CASTOR® and CONSTOR® cask families for safe and economical management of spent fuel.