Re: transmutation

From: Francesco Cerutti <Francesco.Cerutti@cern.ch>
Date: Fri Aug 01 2008 - 16:15:38 CEST

Dear Istvan,

> 1) can FLUKA simulate proton beam, spallation target and transuranium
> material?

yes, FLUKA can simulate a proton beam on a spallation target. Then
neutrons can be transported in 237Np, 239Pu, 241Am, and 243Am, which are
the transuranium materials for which the low energy (<19.6 MeV kinetic
energy) neutron cross sections are available, together with residual
nuclei production.

> 2) does FLUKA follows the decay and transmutation chain during the
> burnout?
> 4) How can I get the mass of each material substance (any daugther
> elements) after the burnout?

In principle you can activate the decay of the radioactive isotopes which
have been produced through nuclear interactions, getting the residual
nuclei mass/charge distribution (in terms of activity, Bq) at a given time
as a function of the irradiation profile you input (the time evolution
is calculated analytically). BUT see the answer to the following question.

> 3) How does FLUKA calculate the fisson rate of transuran elements? Does
> FLUKA recalculate the material substances in the target? Because the
> reaction rates are modified during the material transformations, and of
> course the cross sections is differ from each other in different
> materials. So the primarily material substitution and reaction rates are
> changed as the time goes forward. And it is necessary to use this
> recalculated material/cross sections for the next burnout step.
> And do this to the end of burnout time.

The material composition is NOT CHANGED. The Monte Carlo simulation
consists of creating many independent histories, not talking each other,
under the same frozen conditions you input (beam parameters, geometry and
materials).

Hope this helps
Ciao
Francesco

**************************************************
Francesco Cerutti
CERN-AB
CH-1211 Geneva 23
Switzerland
tel. ++41 22 7678962
fax ++41 22 7668854
Received on Sat Aug 2 10:20:02 2008

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