This article chases clicks by parroting hyperbole from a remembrance service as fact.
This is not the first, nor the worst fire aboard a nuclear submarine. Komsomolets burned and sank with both a nuclear reactor and nuclear warheads on board. The reactor scrammed and was not damaged by the fire; the warheads' biggest risk was leakage of radioactive material.
Losing a nuclear submarine in a fire is a potential catastrophe for the local environment and a tragedy for the fallen crew, but hardly an event that justified the "planetary" scale.