Successful basic criticality experiment done on LR-0 reactor

Contrary to the general impression, a critical state is not something to be feared of, when it comes to nuclear reactors. A critical state is such reactor condition, when the chain reaction is self-sustaining, in other words, number of neutrons introduced into the system is equal to a sum of neutrons both leaked from the system and absorbed by the fuel.  After a more significant change to the reactor internals (e.g. fuel reloading or after installing new experimental device) it is presumed that the physical characteristics of the reactor may have changed. The sense of this experiment is to precisely establish new parameters of the core. In the case of a major change to the reactor characteristics, a basic criticality experiment is required by the state regulator (SONS/SUJB) alongside with the safety report update through several analyses. 
On the 9th of February 2016, through the basic criticality experiment methodology, a criticality was reached on the LR-0 reactor with an active zone on polytetrafluoroethylene (Teflon®) base. Through this experiment, our company has achieved yet another milestone in the research of the insertion zones on the LR-0 reactor with materials based on fluoride compounds. Research on Generation IV reactor systems takes place at the Research Centre Řež under the agreement between the US Department of Energy and the Czech Ministry of Industry and Trade.