Breakdown transient phenomena at the fall-out of the primary circuit cooling pumps at Paks Nuclear Power Plant

A program of the Central Research Institute for Physics for calculating breakdown transient phenomena at Paks Nuclear Power Plant is presented and the drop-outs of the primary circuit cooling pumps are dealt with in detail. The reactor has been equipped with old pumps with low inertia moments but the use of a new type of main pump with high inertia moment is planned. It was established that the most unfavourable drop-out of this main pump type would not cause heat transmission crisis in any subchannel, the two-phase would be limited to some hot channel and the maximum vapour content would not reach 10 per cent. (K.A.)