Re: Japan to switch to MOX? -Reply

[xat@inel.gov (Alden Tschaeche)]

Bob Boston wrote:
> 
> >Correct, ie that is NOT true. Pu-239 and 241 are fissile. Pu-238 is not. I'm
> >not
> >sure about the other Pu isotopes but I suspect that they are also not
> >issile.
> >Can anybody give a definitive answer?
> ___________________________________
> 
> This information is from the TRUPACT-II Safety Analysis Report.  This
> document references all isotopes of fissile concern to Pu-239 fissile
> gram equivalent (FGE).
> 
> Isotope             Pu-239 FGE
> Pu-236             0.0
> Pu-238             0.131
> Pu-239             1.0
> Pu-240             0.0225
> Pu-241             2.25
> Pu-242             0.0075
> Pu-244             0.0
> 
> Hope this helps.
> 
> Robert Boston
> Criticality Safety Engineer
> Lockheed Martin Advanced Environmental Systems
> 208-234-3578 fax 3550
> boston@poc.lmaes.lmoc.com
> 
> These thoughts are my own.
So, does this mean that only Pu-236 and Pu-244 are non-fissile, and that
all other Pu isotopes are?  This sort of contradicts a statement that
Gary Damschen sent me as follows:  "I suspect that much of your
confusion stems from the imprecise use of
"fissile" when referring to nuclides that can be split by neutrons.
Although
technically incorrect, the terms "fissionable" and "fissile" have been
used
interchangeably for a long time. In the currently accepted usage (at
least
in the US <g>), a "fissionable" isotope is one that is capable of being
split by neutrons (the neutron's energy is not considered) - so all
isotopes
of Pu are fissionable. "Fissile" isotopes require thermal neutrons to
initiate the fission reaction, so Pu-239 is fissile but Pu-240 is not.
"Fissible" isotopes require fast neutrons to initiate the fission
reaction,
so Pu-240 is fissible but Pu-239 is not."

Do we still have a definition problem.?  Al Tschaeche xat@inel.gov