I believe that the primary containment on Unit 3 is breached and that there is very limited of no pumping ability left to the Unit. It is very possible that the vessel was breached and is leaking. There is some scuttlebutt among industry people that there was a common valve failure on three units at the plant - all of which are in primary cooling loops. And yes this is a Level 6 event.
Hmmmmmmmmm.
but for a nail a horse
but for a horse a rider
but for a rider, the battle was lost
. . . fascinating how small things tend to have huge consequences.
As the Bible says, . . . in relationships . . . the little foxes spoil the grapes.