16h 19min, apr 25, 1986 y - Xenon build up
Description:
Xenon is a by product of the breakdown of Uranium. Usually at high temperatures the Xenon burns away and is harmless. However when held at half power the xenon doesn't burn away and in fact slows reactivity inside the reactor. This unbalances the reaction inside the reactor and poisons the core.
Added to timeline:
Date:
16h 19min, apr 25, 1986 y
Now
~ 39 years ago