If the rest of the plant is shut down, then operating the spent fuel pool will cost $3 million a year, he added.

"There are more things that can go wrong in the spent fuel pool," he said.

But the plumbing for the spent fuel pool must be kept running.

Are accidents at spent fuel pools considered in this study?

They know nuclear storage in spent fuel pool is a big issue.

It was reported that water in the spent fuel pool might be boiling.

At 17:48 it was reported that water in the spent fuel pool might be boiling.

"I think lots of people have looked at the spent fuel pools and said, 'How can we make it safer?' "

In 2008 the second spent fuel pool started operation increasing the total capacity from 600 to 1600.

I now understand what people are worried the most about is the vulnerability of the No.4 spent fuel pool.