Tests of Nuclear Jet Engines as a New Source of Radioactivity in the Environment

Russia announced that they successfully conducted test of nuclear jet engines in autumn of 2017. Construction details of the tested nuclear jet engine remain unknown, but the general concepts of such constructions are well known. The heat is generated by radioactive decay instead of combustion of liquid chemical fuel. There are two possible sources of radioactive heat: the very active radioisotope source (as in a Radioactive Thermoelectric Generator, RTG) or a nuclear reactor. Simple calculations reveal that the required activity for propulsion of cruise-class missiles is on the order of magnitude of an EBq (10¹⁸ Bq). It is likely, that the mysterious air contamination with ¹⁰⁶Ru/¹⁰⁶Rh, observed in beginning of October 2017 all around Europe was a result of such tests. Tests of nuclear jet engines in open air is a new challenge for radioactivity monitoring systems in many countries. The use of RTG–like radioisotopes is a new situation for which many countries and international organisations are not prepared at all. Another important question is activity released during possible crash, which might happen during a test flight.