Nuclear Engineer: Fuel Rod Fire at Fukushima "Like Chernobyl on Steroids"

From an article at the FireDogLake blog:

The Fukushima Daiichi plant has seven pools for spent fuel rods.  Six of these are (or were) located at the top of six reactor buildings.  One “common pool” is at ground level in a separate building.  Each “reactor top” pool holds 3450 fuel rod assemblies.  The common pool holds 6291 fuel rod assemblies.  [The common pool has windows on one wall which were almost certainly destroyed by the tsunami.]  Each assembly holds sixty-three fuel rods.  This means the Fukushima Daiichi plant may contain over 600,000 spent fuel rods.


The fuel rods must be kept submerged in water.  Why?  Outside of the water bath, the radioactivity in the used rods can cause them to become so hot they begin to catch fire.  These fires can burn so hot the radioactive rod contents are carried into the atmosphere as vaporized material or as very small particles.  Reactor no 3 burns MOX fuel that contains a mix of plutonium and uranium.  Plutonium generates more heat than uranium, which means these rods have the greatest risk of burning.  That’s bad news, because plutonium scattered into the atmosphere is even more dangerous that the combustion products of rods without plutonium.