[ RadSafe ] SL1

Jaro Franta jaro-10kbq at sympatico.ca
Tue Jun 21 19:11:14 CDT 2011

Hi Spencer,

INL's on-line history book has a detailed (9.3MB pdf) account of SL-1 in
chapter 15:


(AECL Montreal office)

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of SFisher373 at aol.com
Sent: June-21-11 7:24 PM
To: radsafe at health.phys.iit.edu
Subject: [ RadSafe ] SL1

Franz et al,
I would say that sabotage is not the correct word to use.  We present  the 
SL1 accident to our students, and I have read the reports, investigations  
etc.  I am at home, so do not have the facts in front of me.  What  happened

was that contrary to what was posted yesterday, they were working on  the 
control rods, not the fuel rods.  The central rod controlled 80% of the  
reactor power.  The work involved stroking the control rods.  For some
unknown, the one individual removed the control rod.  He had broken  up with

his wife on the day of the incident and had his personal belongings in  the 
car.  So was he distracted, was he trying to injure himself to get  
sympathy, was it a murder/suicide (he felt that his wife may have been
with the other operator on duty that day).  This was after the Christmas  
holidays/New Year.  
The magnitude of the excursion was greater than had been predicted.   There 
are accounts that since this was a military reactor, it was known that  
removing the central rod would cause the reactor to overheat and be
What happened was the water turned to steam and the resulting  steam hammer 
produced an effect far greater than predicted.
So it was a human problem, and since no one lived, we will never  know.  
Spencer M. Fisher
Nuclear Theory and Reactor Physics
Authorization Training
Ontario Power Generation.
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