[ RadSafe ] Reprocessing

[George Stanford]

To: Don Mercado:

         Interesting questions -- but let's back up and consider what kind 
of recycling would be worthwhile.  Recycle back into thermal reactors 
(PUREX & MOX) is not the panacea that many picture.  Back-of-the-envelope 
calculations indicate the following (if I've goofed, someone please correct 
me).  All numbers are approximate.

         Only about 15% of the heavy metal in spent LWR fuel can be cycled 
back into an LWR, the remainder being uranium that is almost back to the 
composition of natural uranium.  (It could, of course, be re-enriched -- 
contributing another 15% or so -- or used in CANDUs without 
re-enrichment.)  Of the 15% recycled, some 5% is consumed (0.75% of the 
original fuel), for a net increase of resource utilization of about 15%.

         In other words, if a thermal reactor extracts 5% of the energy in 
its fuel (0.6% of the energy in the mined uranium) in one pass, the second 
pass would bring it up to 5.75% of the fuel's energy, raising the overall 
efficiency to about 0.7%.

         Subsequent passes can contribute little. Very roughly, a third 
pass contains 2.25% (15% of 15%) of the original fuel, of which perhaps 5% 
is burned -- bringing the fuel utilization up to about 5.85%.

         The benefits of MOX recycle are a gain of 15% - 20% in resource 
utilization, and some streamlining of the waste-management problem -- but 
the problem of long-term activity in the waste is only reduced somewhat, 
not eliminated.  MOX with thermal reactors cannot close the nuclear fuel cycle.

         The story is very different with pyrometallurgical processing and 
fast reactors -- a combination that can extract virtually all of the energy 
in the mined uranium (resource utilization improved by more than 10,000%) 
-- and, importantly, consume the long-lived transuranic actinides instead 
of consigning them to Yucca Mountain.

         For a more detailed discussion of the desirability of MOX recycle, 
see the paper "LWR Recycle: Necessity or Impediment?" at
<http://www.nationalcenter.org/LWRStanford.pdf>.

         Fast reactors can live happily on thermal-reactor spent fuel, 
fully closing closing the nuclear fuel cycle.  As I see it, a movement to 
institute recycling in the USA should be focused on pyroprocessing and fast 
reactors.  While MOX is indeed desirable for despoiling weapons-grade 
plutonium, constructing an extensive MOX infrastructure for civilian fuel 
would be a serious waste of resources.

                 Best regards,

                         George Stanford
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

At 09:51 AM 6/21/2005, Bernard Cohen wrote:
   ---I am quite sure the Carter decree was reversed during the Reagan 
administration, so there is no legal block to reprocessing in U.S.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

At 04:24 PM 6/20/2005, Mercado, Don wrote:
I have a question on spent fuel reprocessing. What will it take to get
spent fuel recycling started? Can it be done in the U.S. in spite of J.
Carter's ban? Would JC's Presidential decree have to be reversed and
what does it take to do that? Has a Presidential decree been reversed
before while that President was still alive? Could we hire France or
some other country to reprocess it for us while that process moves
forward?

Just some speculation while waiting for some return phone calls. :^)

Donald P. Mercado
Radiation Safety Officer
Explosives Safety Officer
Lockheed Martin Space Systems Company
O/9K-2S, B/157
1111 Lockheed Martin Way
Sunnyvale, CA 94089
Ph. (408) 742-0759
Fx. (408) 756-0504
Don.Mercado at lmco.com
"Life is not a journey to the grave with the intention of arriving
safely in a pretty and well preserved body, but rather to skid in
broadside, thoroughly used up, totally worn out, and loudly proclaiming
-- WOW!!! -- What a Ride!!!"


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