Elaboration of the thermophysical instruments for non-destructive examination of tightness and gas parameters inside power reactor fuel rods

The developed thermophysical method and automatic measurement instruments for express non-destructive leak tightness and gas parameter inspection inside power reactor fuel rods both in the process of their production at a plant and under hot cell, cooling pool or storage conditions are described. The method of gas parameter measurement based on examination of thermal convection that aroused in gas volume of rod plenum by technical instruments. The developed technique allows us determination of the internal gas pressure in every rod with high accuracy and of the partial pressure of every main constituent in gaseous mixture inside irradiated rod. (author)