Failure pressure and failure mode of the bolted connection for the large component port in German PWR containments

For the recent German pressurized water reactors, containment failure due to overpressurization is controlled by the mechanical behavior of the bolted connection between the containment shell and the large component port. Of essential influence is also the sealing box which covers the bolted connection. Both parts have been investigated. For the pressurized water reactor Philippsburg containment overpressurization leads to a local failure between 12.9 and 13.7 bar. For the Konvoi-type of reactor, the critical pressure may reach values up to 14.3 bar. In this case, however, global failure with severe mechanical damage cannot be ruled out. (orig.)