This work has been released into the public domain by its author, Tungsten. This applies worldwide. In some countries this may not be legally possible; if so: Tungsten grants anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law.

This diagram demonstrates the defense in depth quality of nuclear power plants. 1st layer of defense is the inert, ceramic quality of the uranium oxide itself. 2nd layer is the air tight zirkonium alloy of the fuel rod. 3rd layer is the reactor pressure vessel made of steel more than a dozen centimeters thick. 4th layer is the pressure resistant, air tight containment building. 5th layer is the exclusion zone around the reactor.