What is "thoron"

Usage examples of "thoron".

Captain, a thoron radiation pulse drove the foreign organism out of your brains.

While we fret over the fate of these poor few, thoron radiation is building up in your atmosphere.

Briefly, the captain told Nor-dine about the threat of thoron radiation killing everything on Gemworld in less than six days.

I also note that thoron radiation is reaching critical levels in some areas.