Year
2001
File Attachment
34925.PDF42.1 KB
Abstract
Our company „CEZ Prague„ decided on a new technology in the storage of spent nuclear fuel in the year 1991. The main feature is due dual purpose metal cask CASTORÒ 440/84 for 84 assemblies of the type VVER 440. The first stage of building was designed for 60 casks, currently 40 casks are stored. The CASTORÒ 440/84 is a dual-purpose cask and provides dry storage in a 100 % helium atmosphere. The cask is monitored according to the design by a system which measures the pressure in the gap between the primary and secondary lid. Another monitoring system is the measurement of surface temperature. For shipment, the cask is transported on a special railway wagon designed only for this reason. For application of the new technology, we had to provide many requirements. The most important were the reracking of storage pools, new universal nests in the loading pit, new service places in the reactor hall, shock absorbers, etc. In December 1995, the first CASTORÒ cask was placed into the storage hall. Until then we performed „trial„ operation for a duration of 14 months. The most important requirement of the State Office for Nuclear Safety was the necessity of special equipment for back cooling of the cask. Dukovany's fuel was stored in the former Czechoslovakia in the Slovak power station of Bohunice. A total of 9 CASTORÒ casks were transported between both republics. By the last transport, special procedures for back cooling of the cask were performed, and the last cask was completed in the Dukovany NPP area. Main conclusions: In 6-years of safe operation, 40 casks have been placed in the ISFSF; the storage operation belongs to the best practices in the Dukovany NPP. Perspectives: A second stage ISFSF is under preparation now; our company had chosen the winner of the competition - the advanced CASTORÒ 440/84M cask. The next building will be more than two times bigger than the current ISFSF. The proposed life time is approximately 60 years.