Separation of isotopes in the BA and as FP

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topefo
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Separation of isotopes in the BA and as FP

Post by topefo » Sat Feb 27, 2021 8:53 pm

Dear Serpent2 developer team,

As a new version of Serpent2, version 2.1.32, has recently been released,
I would like to know if it is now possible to separate the tracking of some isotopes
commonly used as fuel BA from the ones built-up as fission products, e.g., Gd-155?

One would like to treat Gd-155 in BA differently, for example,
in a nodal core simulator due to its strong self-shielding effect compared to
the Gd-155 built-up during FP decay and capture processes. The homogenized
microscopic cross sections provided to the nodal simulator should reflect
this fact by providing a different isotope ID for each of them in the "set mdep"
input card.

A common way to make this separation in deterministic lattice codes is to
assign a different ZAI to them, such as 641550 and 642550.

Cordially,
Petri

Ana Jambrina
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Re: Separation of isotopes in the BA and as FP

Post by Ana Jambrina » Sat Feb 27, 2021 11:13 pm

Micro-depletion feature allows to set for a given universe (where spatial homogenisation is performed) the nuclides within materials to track for the specified decay channel(s)/(neutron induced) reaction(s)/ product nuclides of each decay/reaction - see further description: 'mdep' card .

Additional information about this feature can be found at: [url=http://montecarlo.vtt.fi/mtg/2020_Munich/Rintala1.pdf]Microscopic group constant with Serpent[/url,] presentation given by A. Rintala at the 10th International Serpent User Group Meeting.
- Ana

topefo
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Re: Separation of isotopes in the BA and as FP

Post by topefo » Tue Mar 02, 2021 12:40 am

Dear Ana,

Many thanks you for your answer. I am more interested in the possibility of using 2 different library IDs for the same isotope
in the same homogenization region. I therefore apologize that my original question was formulated in a quite confusing way.

For example, would it be possible to add the following lines in the ".xsdata"-file:

64155.82c 64155.82c 1 64155 0 154.922630 900 0 /pgm/external/serpent2/xslib_mcnp6/endf71x/Gd/64155.712nc
Gd-155.82c 64155.82c 1 64155 0 154.922630 900 0 /pgm/external/serpent2/xslib_mcnp6/endf71x/Gd/64155.712nc
64255.82c 64255.82c 1 64155 0 154.922630 900 0 /pgm/external/serpent2/xslib_mcnp6/endf71x/Gd/64155.712nc
Gd-255.82c 64255.82c 1 64155 0 154.922630 900 0 /pgm/external/serpent2/xslib_mcnp6/endf71x/Gd/64155.712nc

In this way one could define and track the Gd-155 in the BA (64255.82c) separately from the Gd-155 (64155.82c) created
as a fission product and could define 2 sets of microscopic cross sections for them by the "mdep" card:

set mdep 0 236.390625 7 fuel_400_BA

641550 101
642550 101

Note, this is just an example to illustrate what I mean.

Cordially,
Petri

Ana Jambrina
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Re: Separation of isotopes in the BA and as FP

Post by Ana Jambrina » Tue Mar 02, 2021 2:13 am

Check set ba option, available in Serpent 2.1.32 - It defines isotopes handled separately as burnable absorbers.
- Ana

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