Re: Dispersal of Spent Fuel -Reply

["John J. Sadler" <jj.sadler@baylordallas.edu>]

Not being a commercial nuke HP, I am relatively inexperienced about fuel 
"ponds" so bear with me.  Please send any comments to me.  Make them NICE 
comments since I am such a sensitive guy....guess I won't be hearing from 
Mr. Schoenhofer....

OK, follow my "logic", keep a sense of humor...this IS supposed to be an 
educational media....

Spent fuel rods are kept in pools to cool them down after refueling, 
correct?  As I understand it, if the cooling water gets too cold, it can 
become a very effective moderator and criticality can occur, correct? 
(Hence, the criticality alarms in the plant..) Now, one of the beauties 
of water and why it is such a good moderator is that it can somewhat 
control itself.  As more fissions occur during the criticality, more heat 
is released and the density of the water drops.  The conditions which 
allowed this undesired criticality are now corrected since water 
temperature is raised above the point of concern.  I understand the 
radiation hazard involved but not the explosive hazard.  A prompt 
criticality hazard created from a large addition of positive reactivity 
such as that delivered to the SL-1 reactor can cause the water to flash 
to steam and result in a steam explosion.  Unless the fuel rods in the 
pool are stored too close together and the mean free path of the neutrons 
from one cell reach another cell, how can an explosion occur in a spent 
fuel pool?  Also, someone mentioned gasses which are released which could 
create an explosion hazard.  What are these gases, hydrogen?

My hat's off to you plant hp's is all this is true!!  Do you all collect 
hazardous duty pay??
-- 
John J. Sadler
Medical Physics
Baylor University Medical Center - Dallas
3500 Gaston Avenue  H-0539
Dallas, TX  75246     (214)820-8516
jj.sadler@baylordallas.edu  --or--  jjsadler@aol.com
"Very funny, Scotty, now beam down my clothes..."