Measures for examinations of CASTOR registered casks as consequence of a signal from the container surveillance system in the interim storage facility

Actually about 920 loaded of CASTOR registered with pressure switch are worldwide in interim storage facilities connected to a cask surveillance system. This system surveys the container status with respect to the functional efficiency if the tightness barriers. For this purpose a pressure switch is mounted in the secondary cask cover that controls the pressure between the primary and secondary cask covers. This system is operated during the complete interim storage time. Since start-up of the pressure switch system in 1983 signals in the container surveillance system were observed for about 2 % of the pressure switches. Each of these events was caused by a defect of the pressure switch. The presented contribution includes information on the tightness barriers, the pressure switch construction, the surveillance system and the test procedures in case of signaling of the container surveillance system.