“Radiation is feared”
IOW, they don’t know whether there actually *is* a radiation leak, they don’t know where the explosion occurred.
They don’t know anything.
Precisely what I have been trying to tell you now for about 3 days. They have no clue to know what is going on inside the reactor. Absolutely no clue at all. We had to wait 5 years to learn that TMI had suffered a significant partial meltdown. In that scenario, it is always prudent to assume the worse. Why would you assume the best if you knew no one on the planet had a clue ?