Tokyo Electric Power Company admits Fukushima Daiichi’s Reactor 1 has a damaged core.

It would explain the high levels of radioactive water coming from the building.  TEPCo thinks the core is breached, allowing radioactive steam to enter the containment vessel.  That’s mixing with the water in the containment vessel, which is also leaking.  To make the problem worse, the fuel rods in the core are still partially exposed, and breaking down.

TEPCo wants to continue injecting water, which they are doing at a rate of 600 tons per hour.  The Japanese Nuclear and Industrial Safety Agency is warning that they think Reactor 1 is damaged so much that it can not handle anymore water injection.  If TEPCo is injecting water at 600 tons per hour, and they still can’t cover the exposed fuel rods, obviously the water is leaking out faster than they can put it in.  That suggests sizable damage.

So, TEPCo is dealing with a conundrum; adding more water could further damage the structure, making things worse, but not injecting water will expose more fuel rods, making things worse.