[ RadSafe ] Zirconium Cladding of Fuel Rods - Reaction With Water

Jeff Terry terryj at iit.edu
Sat Mar 12 20:07:17 CST 2011

Hi Roger, 

At temperatures exceeding 1000 C, Zr reacts exothermically with water producing ZrO2 and H2. 
This is a well known risk of emergency quenching. 

A detailed paper on this effect can be found at:



Jeff Terry
Asst. Professor of Physics
Life Science Bldg Rm 166
Illinois Institute of Technology
3101 S. Dearborn St. 
Chicago IL 60616
terryj at iit.edu

On Mar 12, 2011, at 7:33 PM, Roger Helbig wrote:

> The NEI advised that the Hydrogen gas that is the probable cause of the
> explosion at Fukushima #1 Reactor was generated when the Zirconium cladding
> of the fuel rod was exposed - how did this exposure generate the Hydrogen
> gas?
> "It appears that as the level of coolant in the reactor vessel lowered, a
> portion of the top of the uranium fuel rods was exposed. This may have
> caused zirconium cladding of the fuel rods to react with water to create
> hydrogen. This hydrogen was vented, then somehow ignited, causing the
> explosion."
> Web Elements says that Zirconium does not react with water under normal
> conditions
> Reaction of zirconium with water
> "Zirconium does not react with water under normal conditions."
> Roger
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