JRC ISPRA sealing-bolts for containers - Results of first field tests with spent fuel containers (MEB) at BNFL Sellafield Nuclear Facility

For a number of years JRC Ispra has been involved in the development of ultrasonic seals for International Safeguards. Good results obtained with the VAK-III seals for BWR fuel assemblies have encouraged us to apply a similar technique to the safeguarding of fuel containers. Since 1985 a MARK-II ultrasonic sealing-bolt has been developed whose purpose is to replace one of the bolts normally used to close a container's lid. In agreement with BNFL plc a field test program has been organized at their Sellafield facility. MARK-II sealing bolts were installed on a lid in a storage pond during summer 1986. A first verification exercise was carried out in December 1986 whereby all seals could be checked properly with the handling tools and instruments brought from Ispra. A second verification exercise was then planned and prepared for June 1987 for which new modified sealing-bolts were built. Unfortunately, owing to cleaning operations at the pond site, this second exercise had to be postponed at the last moment, on request of BNFL. It would be now scheduled for September or October 1987