RE: So, is reprocessing in America's future?

["Franta, Jaroslav" <frantaj@AECL.CA>]

Raymond Shadis wrote :



> Franz,

 Quite so! On line refueling. Have you references that confirm they pulled

their fuel at low burn-up right under the noses of Canadian and IAEA

oversight? Does anyone have data or references regarding the Pu-240 levels

in the fuel the Indians "scavenged" for their bomb? I apologize for the use

of the term , "scavenge" , I meant it in the loose sense of drawing off a

minor portion. Thank you for your patience.                          Ray

<><><><><><><><><><>



COMMENT :  NOT SO FAST !!  ....many years ago - I guess after the TMI

accident - before I joined AECL, I asked whether the CANDU fuelling machine

could be used to "defuse" a potential meltdown accident by simply

de-fuelling the reactor core (or at least the central part of it), to reduce

the heat load. To my surprise, I was told that the machine works only very

slowly, so there is no question of it being useful for such a purpose.

Now I know better. 

Turns out the fuelling machine operation is so slow, you could NOT shuffle

the thousands of fuel bundles in & out of the core fast enough to get the

required low fuel burnup that gives bomb-grade Pu. At best, you could do it

with a few specific pressure tubes within the reactor, but that would give

you only a small fraction of the "theoretical" yield, and it would be plain

as day that you are trying to do something weird (and as someone else said

already, you can't just walk out of the plant with spent fuel bundles under

your coat anyhow....). 

Alternately, you could do periodic shutdowns to give yourself time to do

complete core refuelling, but this would also be very obvious to IAEA

inspectors, and you would essentially destroy the usefulness of the plant as

a steady power-producing source. It is for the latter reason that the

military find it much more economical to just build dedicated Pu-production

reactors instead of entire plants with steam turbines, condensers, cooling

towers, auxiliary process systems, etc., etc. 

I don't know that much about the Russian RBMK reactors, but I suspect they

have the same limitations as CANDUs. Of course the Russians - like the US -

have/had plenty of dedicated Pu-production reactors. I also think that RBMKs

have a close relationship to their Pu-production ancestors, but only for

reasons of convenience/experience. The US too once considered developing

Hanford-type reactors into full-blown power plants.... 

....I was in the audience at Dr. Edward Teller's last visit to Montreal some

years ago, where he recounted his story of the safety committee which

rejected that idea, on the grounds that the water-cooled, graphite-moderated

reactors suffered from precisely the type of potential instability that lead

to the explosion of the Chernobyl reactor.

As for India, it is well known that their Pu came from the CIRUS research

reactor - although this fact is frequently ignored, on purpose, by the media

and by antinuke activists, in order to play up the weapons proliferation

issue vis-à-vis foreign NPP sales. For details, PLEASE see the following

web-posted discussions:



"Did India use a CANDU reactor in the 1970's to make an atomic bomb?" at

http://www.freenet.carleton.ca/~cz725/cnf.htm#x1

"What is the relevance of Canadian technology to India's recent nuclear

weapons tests?" at http://www.freenet.carleton.ca/~cz725/cnf.htm#x1_2

and

"How easily can an atomic bomb be made with spent CANDU fuel?" at

http://www.freenet.carleton.ca/~cz725/cnf.htm#x2 





A couple more points : Since CANDUs use natural uranium, they can't get as

much fuel burnup as PWR-type reactors (actually less than about one third as

much -- 10GWd/tonne vs. some 30 - 40 GWd/tonne for PWRs) . Its NOT enough to

make a big difference in the Pu-240, 241 & 242 content (for bomb-building

purposes), but if you REALLY believe that the Pu isotopics don't matter,

than the preferred way to go for your bomb-building effort is the PWR, since

the total concentration of Pu in the spent fuel - all isotopes combined -

will be higher by about the same ratio too.

Lastly, nuclear weapons decommissioning in recent years has demonstrated the

relative importance of weapons grade Pu versus weapons-grade Uranium -- the

surplus quantities of the latter (U-235) are over TEN TIMES as much as the

former, measured in the hundreds of tonnes, rather than mere dozens of

tonnes.

Please inform yourself before jumping to the conclusions propagated by

antinukes & sympathetic media types.

Thanks.



Jaro

frantaj@aecl.ca



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