• The second series of the EC funded project included five experiments for the investigation of the break location and CMT scaling (smaller CMT) on the PSIS behaviour. PACTEL operators made small changes to the CMT instrumentation to better detect CMT level and thermal stratification behaviour. The PSIS consisted of a Core Make-up Tank, which had connections to downcomer through an injection line and to one cold leg through a pressure balancing line.

The experiment series also investigated the CMT behaviour in a situation where the CMT is initially full of hot water. This may happen in the AP600 plant if the injection line check valve leaks. The programme also included an experiment without flow distributor (sparger) in the CMT.