Looks like Russia has, in fact, had another nuclear accident. More radiation will be released into Europe as a result.
Looks like they were testing their new design for a small Mach-5+ nuke powered missile capable of “traversing the globe indefinitely”.
Such a weapon would be impossible to defend against since it would be moving far too fast for any MDS to shoot down, and even locating its precise position at any given point would be difficult.
“Russia has belatedly admitted that the mystery explosion which released radiation into the air last Thursday, triggering warning alerts across towns near the northern port cities of Arkhangelsk and Severodvinsk, involved a “small-scale nuclear reactor”.