The physical safety of people and the protection of infrastructure from accidents caused by man-made, accidental and terrorist acts are still one of the major challenges for humanity. The most common of the many causes of accidents are industrial and terrorist explosions and fires, often accompanied by toxic gases and uncontrolled sources of radiation. Therefore, fast / rapid identification of such threats, processing the information and timely informing of emergency or other structures are the only way to prevent them, minimize and/or avoid the serious negative consequences. In this regard under high-risks are all kind of critical infrastructure facilities (tunnels, underground structures and confined spaces) and crowded civilian/ social places (transportation hubs, airports, shopping malls, etc.) Georgia (as well as European countries) has adopted the National Security Concept (NSC-GEO (1) .pdf), where in the first place in the list of main threats is "terrorist acts organized by the Russian Federation from the occupied territories of Georgia" and at the  fifth place is " International Terrorism and Transnational Organized Crime. " The situation is further complicated due to the ongoing Russia-Ukraine war in the Black Sea region and its consequences in future. In the civil field, the most dangerous increased threat spaces in terms of technogenic (man-made) and accidental explosions are tunnels, in particular coal mines, nuclear power plants, radiation sources and waste storage areas.   As annual statistics show, many miners around the world die due to methane and coal dust explosions in coal mines. Cases of toxic gas poisoning are frequent. During a single explosion in a Turkish (Soma) mine killed 301 miners. Recently the one of the last such accident occurred on January 31 of this year, 2022 in the Tkibuli (Georgia) coal mine. Besides there are also very serious consequences due to the fires at radiation sources, provoked by emergency or accidents, which leads to dangerous increases in radiation levels and environmental pollution.

Protecting facilities (especially tunnels and underground spaces) from accidental and terrorist explosions and fires, taking into account their accompanying toxic gases, and in some cases from increased radiation, still remains as highly topical problem.