Are they bluffing? I don't think so.

The storage pond was empty. There are no spent fuel rods there,

The North Koreans were using the Iranian example as well, saying that if they are allowed to keep a reactor, why can't we?

Both of them blinked,

time is not on your side. As time goes by, we are increasing our arsenal.

This is unusual for it to have gone on sometime without contact.