Davis Besse Reactor Core
Manifesting Cerenkov Effect Radiation!

Fuel Bundle being lifted out of the core by a Refueling Bridge Grapple

I thought it would be great for my web visitors to see a picture of the eerie blue glow
of water around the control rod assemblies in the reactor,  at the DBNPS station!

A brief(?) explanation may be in order here, for those unfamiliar with this "glow":

Workers on the refueling floor and in the fuel handling area will see the water
immediately surrounding the irradiated fuel bundles glowing with a blue color.
This is known as the Cerenkov Effect,  or Cerenkov Radiation.  Below is an
explanation of this phenomenon:

When high energy radioactive decay occurs, as it does with recently irradiated
fuel bundles, some electrons are emitted at speeds greater than the speed of light
(Imagine that!!!) in water.  However, when the electrons leave the fuel bundle,
they interact with the water and rapidly slow down.  The wavelength at which
the energy is then released is the same as that for blue light.
Thus the water glows blue, as seen in the above picture.

The effect can appear to be quite eerie, especially since it it not the fuel bundle
that actually glows, but rather just the water that is surrounding the fuel bundle
assemblies.  As the radioactivity level in the fuel decreases over the next few months,
this glow will eventually fade away.

In the above picture,  look at the fuel bundle being pulled out of the core, it has that
glow all over it, seen on lower left corner of the circular core area.  There is a nice
glow also seen below the pulled out bundle in the hole between presently installed
fuel assemblies!  Remember, the water does the glowing, not the irradiating bundles!
Here is another picture, this time showing the completely refueled configuration.
The latest pictures were taken during DBNPS 13th Reactor Refueling



Photo and explanation are courtesy of Jim Adams, who is a co-worker at DBNPS!
He is a former U.S. Navy Nuclear Submariner who served tour of duty on the 
Lafayette Class "Boomer" Submarine, the  SSBN 619 Andrew Jackson!
Thanks, Jim!

Back to my DBNPS Nuclear Page

Learn More! 
Resources on the Cerenkov Radiation Effect:
Cerenkov Radiation   Site 2
Pavel Alekseyevich Cherenkov – Biography
On Cerenkov And Bremsstrahlung Counting