Based on the principle of hydraulic control rod driving system(HCRDS), the paper gives a new scram method, which makes the inside pressure of step cylinder discharge, to solve the scram problem of HCRDS in control rod hang up accident and inversion conditions, and some experiments were caried out with the 1∶1 experimental loop of the HCRDS for the 200 MW nuclear heating reactor(NHR200).

The experimental results of stepup, stepdown and scram in normal condition and depressurization condition indicate that control rod can stepup, stepdown and scram normally in depressurization condition.

Whether the structure of cantilever screen surface is rational or not is not only related to fully exert the second vibrating characteristic of cantilever screen,but also related to screening efficiency,output of per unit area,using longevity,servicing and so on.

Establishing the theoretic mechanical model of ZRBF vibrating screen and studying its moving character;