[ RadSafe ] Plutonium from Power Reactors

Brennan, Mike (DOH) Mike.Brennan at DOH.WA.GOV
Thu Apr 10 13:23:01 CDT 2008

I agree with others: the question is not silly.

There are a number of aspects to the answer.  One is that some fissile
isotopes are better than others in terms of having bigger
neutron-capture cross sections for (for the neutron energy level of
interest) and shorter mean-times between absorbing a neutron and
fissioning, releasing energy and more neutrons.

Another factor is ease of separation.  It is way easier to separate
elements than isotopes, which is one of the reasons that Pu-239/240 is
more widely used in weapons than U-235 (there are other reasons, too).
There are ways of constructing fuel and designing and operating reactors
that produce more of the desired Pu isotopes and fewer of the undesired
isotopes.  Commercial reactors, particularly ones that have to be shut
down to have fuel rods removed from them, and tend to burn the fuel for
a couple years, produce more of the undesirable Pu isotopes that are
very difficult to remove from the desirable ones.

If you have too many of the wrong atoms in weapons material you won't
get a very big explosion.  I am skeptical that using commercial reactor
fuel as your source of Pu you could get an energy release from fission
that would be larger than you could get from chemical reactions much
easier to engineer (Fuel-air effect explosions coming to mind, though
there are probably others).

One of the things almost always skipped over, and is ignored in the
article you linked, is that processing fuel, especially fuel you shut
down the reactor to take out, is difficult in the extreme.  Fresh spent
fuel is kill-you-real-time hot, thermally as well as radiologicly.  The
facilities needed to do the physical and chemical processing of the fuel
are huge and expensive.  I don't believe it is realistic to think a
non-government would have the resources.  

Now, I am a geeky as the next guy, and I can sympathize with someone
having a cool antineutrino detector and want to come up with a neat and
lucrative use for it.  The discussion about using them to analyze fuel
in research reactors is interesting, and I do not have an opinion as to
whether it is doable or desirable.  But using it to monitor commercial
power reactors is something I am skeptical about. 

-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On
Behalf Of Dan W McCarn
Sent: Wednesday, April 09, 2008 11:17 PM
To: radsafe at radlab.nl
Subject: [ RadSafe ] Plutonium from Power Reactors

Hi -


Please forgive me if this is a silly question: I thought that plutonium
produced in power reactors was not suitable for building weapons because
of significant ingrowth of several Pu isotopes making it unusable for


Could someone please clarify the proliferation issues of Pu produced in
power reactors under normal burnup conditions? 


The following google hit seems to imply something different from my


Or is the antineutrino detector focused on research reactors?


Dan W McCarn, Geologist

Albuquerque & Houston


Antineutrino Detector <http://www.spectrum.ieee.org/apr08/6129>  Could
Spot Atom Bomb Cheats IEEE Spectrum - New York,NY,USA The IAEA could get
much-needed monitoring help from a new type of detector that researchers
at the Lawrence Livermore National Laboratory (LLNL), ...
29> See all stories on this topic


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