Tokyo Electric Power Company says there are signs that the injection of nitrogen into Reactor 1 is working to prevent an explosion. But it might be too soon to tell, the nitrogen injection operation will take six days.

Fukushima Daiichi’s Reactor 1 core began build up of hydrogen gas, probably caused by the melting of the outer casing of partially exposed fuel rods. In normal circumstances reactor cores have nitrogen in them to counteract any hydrogen build up, but TEPCo officials think Reactor 1’s core is breached, leaking out the nitrogen.

If that’s true then the six day nitrogen injection operation could be only temporary.