Re: fissile, fissionable

[Bates Estabrooks <besta@tis.eh.doe.gov>]

Ron L. Kathren wrote:
> 
> Franz --
> 
> The fact that a selfsustaining or supercritical state can occur with
> neutrons above thermal energies in no way alters the definition of
> 'fissile', a term that really was developed for reactor work, specifically
> because of the moderator.  Some specific nuclei (U-233, U-235, and Pu-239)
> have very large fission cross sections at low energies, and are thus fissile
> and useful as reactor fuels.  But, one can also have a 'fast' reactor, as in
> the LMFBR.
> 
> Hope this helps; your English is fine, and I thank you for the kind words.
> 
> Ron
> 
> >At 18:52 24.01.1997 -0600, you wrote:
> >>I guess I'll put my 2 cents worth in;  fissile means capable of supporting a
> >>self sustaining chain reaction by thermal neutrons; fissionable means
> >>capable of undergoing fission (which virtually every nuclide except maybe
> >>hydrogen-1 can), given the right conditions.
> >>
> >>Ron Kathren
> >>rkathren@tricity.wsu.edu
> >>
> >...................................................
> >
> >Ron,
> >
> >In spite of my limited knowledge of English I have a feeling, that your
> >definition is right, especially since everything can be "fissioned" with
> >atoms, ions etc, depending on the energy and the nucleus involved. But how
> >about nuclear fission bombs - there are no thermal neutrons!
> >
> >Franz
> >Schoenhofer
> >Habichergasse 31/7
> >A-1160 WIEN
> >AUSTRIA/EUROPE
> >Tel./Fax:      +43-1-4955308
> >Tel.:          +43-664-3380333
> >e-mail:                schoenho@via.at
> >
> >
> >
Just to "chime in" on this one, in response to Franz' question regarding
bombs, the issue there deals with fast, PROMPT neutrons, and
confinement.  Reactors are controlled primarily with DELAYED neutrons.

Regards,
-- 
Bates Estabrooks
Westinghouse Elec. Corp
WIPP
P.O. Box 2078
Carlsbad, NM 88220

besta@tis.eh.doe.gov
505-234-8470
fax:505-885-4562


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