AW: [ RadSafe ] Article on Wired on Thorium reactors

[George Stanford]

(1)  FRANZ:  You say

      "the uranium supply is limited first of all by the cost
      of mining. Even the use of weapons uranium and
      downblending will give only a few years or decades
      of postponement of serious problems. . . . At this
      time of history the use of breeder technology seems
      to be politically impossible to choose."

         Let's all hope that that political attitude will soon change.
The current thermal reactors extract less than one percent
of the energy in the mined uranium.  MOX recycle cannot
improve that efficiency by more than 15% or so.

         Fast reactors, however can extract the other 99%, or
close to it.  Back in 1983, B. L. Cohen showed that, with fast
breeders, uranium can supply the world's energy until the sun
engulfs the earth -- in other words, uranium is just as inexhaustible as
the other "renewables"  -- and it's much more available for bulk use.
Given that efficiency, the cost of mining is virtually irrelevant; even
extracting uranium from seawater becomes economically practical.

Reference: B.L. Cohen, Breeder reactors: A renewable energy
source, American Journal of Physics, vol. 51, (1), Jan. 1983.
I have a PDF version, available on request.

(2)  RADSAFERS:  U-233 is indeed a splendid material for bombs,
provided it is not contaminated with U-232, which is extremely
radioactive.  In a thorium reactor, Th-232 becomes Pa-233, which
decays to U-233 with a 27-day half-life.  Thus it is possible in
principle to get isotopically pure U-233 by chemical separation of
Pa-233 before it decays.  I seem to recall that a practical method
of doing that has been devised, but I can't find the reference.
REQUEST : Does anyone out there know of such a paper?

         Thanks.

                 George Stanford

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
At 01:48 PM 7/7/2005, Franz Schönhofer wrote:
Marco,

I slightly disagree: The argument of avoiding plutonium is of course funny.
Until now I have not heard of nuclear weapons constructed from U-233. I
know, that the possibility exists. Rather I have heard at the International
Atomic Energy Agency in Vienna, Austria, some years ago a paper which dealt
with the possibility of a thorium fuel cycle and I have to say that this
seemed to me to make sense.

Many scientists seem not to be aware, that the uranium supply is limited
first of all by the cost of mining. Even the use of weapons uranium and
downblending will give only a few years or decades of postponement of
serious problems. Mixed oxide fuel elements could give a few more decades,
if their use will hopefully not be stopped by political interventions. At
this time of history the use of breeder technology seems to be politically
impossible to choose. Therefore the thorium fuel cycle should be seriously
investigated. As far as I understood, there are huge resources of thorium in
this world, exceeding the uranium resources by orders of magnitude.

I wonder, what the opinion of the RADSAFE community is. Most of all I
believe that there are colleagues out there, who might know much better than
I do....

Best regards,

Franz

Franz Schoenhofer
PhD, MR iR
Habicherg. 31/7
A-1160 Vienna
AUSTRIA
phone -43-0699-1168-1319


 > -----Ursprüngliche Nachricht-----
 > Von: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] Im
 > Auftrag von Marco Caceci
 > Gesendet: Donnerstag, 07. Juli 2005 11:27
 > An: radsafe at radlab.nl
 > Betreff: [ RadSafe ] Article on Wired on Thorium reactors
 >
 > For everybody's amusement:
 >
 > An article on
 > http://www.wired.com/news/technology/0,1282,68045,00.html?tw=wn_7techhead
 > in which a funny argument is presented: in order to avoid Pu proliferation,
 > let us burn Th (and why not, increase taxes along the way).
 > The gentleman who wrote that apparently is not concerned with the
 > proliferation risk posed by U233.
 >
 > Marco
 >
 >
 > _______________________________________________