Reduction of the Kinetic Energy of Potential CEDM Missile

A control element drive mechanism (CEDM) is considered to be a postulated missile in the reactor containment building. There is a missile protection system to absorb the missile kinetic energy from the CEDM missile during an accidental condition. Once a CEDM nozzle breaks, reactor coolant jet discharges from the nozzle, then it impinges on the bottom of the CEDM, and gives a thrust force to the CEDM missile until it impacts on the missile barrier. The jet velocity has been previously calculated by Bernoulli's equation or experimental data so that it produced very conservative kinetic energy and caused difficulties in the design of the missile barrier. In order to reduce the excessive conservatism, the jet is assumed to be a two-phase critical flow with the Fauske slip model, and various jet impingement models on the CEDM are presented