How does Serpent handle missing cross-section libraries during depletion?

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froberto
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How does Serpent handle missing cross-section libraries during depletion?

Post by froberto » Tue Aug 03, 2021 7:53 pm

I am trying to model an irradiation experiment and compare it to ORIGEN-S results.
The experiment is a cylinder of Co-59 and I have large discrepancies for the Co-60 values (see figure).
I am using the cross-section library endfb7 for the simulation.
However, Co-60 is missing in this library.
So my question is, how does Serpent handle the reactions affecting this isotope?
As the isotope is missing I would assume that the simulation doesn't consider the reactions affecting Co-60 - i.e (n, alpha), (n, gamma), etc. and that's why serpent doesn't produce any Co-61 whereas ORIGEN-S does.
Is my understanding correct?
Is there a way to prevent this from happening?
Thanks!
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Ana Jambrina
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Re: How does Serpent handle missing cross-section libraries during depletion?

Post by Ana Jambrina » Tue Aug 03, 2021 9:01 pm

Are you using the same nuclear data set in both simulations? cross sections for neutron-induced reactions, decay data, fission products yields, etc. E.g. it is customary to complement ENDF/B missing data in ORIGEN-SCALE with JEFF nuclear data, particularly the activation file.

Serpent manages the reaction channels and forms the transmutation pathways based on the data available from the cross-section libraries. (See a summary of the simulation in the ".out" file or check the cross section libraries to verify the missing data. Consequently, you can confirm whether the nuclear data are or are not included in the calculation).
- Ana

froberto
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Re: How does Serpent handle missing cross-section libraries during depletion?

Post by froberto » Tue Aug 03, 2021 10:05 pm

Thank you Ana for your response!

I am using ENDFB7 for both simulations.
ORIGEN-SCALE complements the missing data with JEFF.
I was wondering if Serpent did something like that as well.

The .out file shows effectively that Co-60 is not included:

Code: Select all

   20   1  26058.03c     03c  TRA   26  58 0   57.93368   300.0       stable  -BAD--T--------R----  iron 58 (Fe-58)
   21   1  27058.03c     03c  TRA   27  58 0   57.93580   300.0  1.13217E-07  -BA---T--------R----  cobalt 58 (Co-58)
   22   0  27059.03c     03c  TRA   27  59 0   58.93317   300.0       stable  IBAD--T-I------R----  cobalt 59 (Co-59)
   23   4  28058.03c     03c  TRA   28  58 0   57.93570   300.0       stable  -BA---T--------R----  nickel 58 (Ni-58)
Serpent simulations will not be producing any products from the irradiation of Co-60.
Is there a way to go around this?
Are there any standard procedures for conducting activation analyses with Serpent?

Ana Jambrina
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Re: How does Serpent handle missing cross-section libraries during depletion?

Post by Ana Jambrina » Tue Aug 03, 2021 10:50 pm

If you are aiming to produce a comparative study between ORIGEN and Serpent, you should use the same nuclear data in both or account for the discrepancies in the results due to the data. 
The problem could be addressed in different ways:
- Re-built the ORIGEN-S data libraries using only ENDF-B/VII evaluation data (probably not what you are looking for, since those nuclides will not be included either here).
- Run both simulations with JEFF nuclear evaluation data.
- Built new libraries for Serpent based on ENDF-B/VII, consistently complementing them with nuclear data from JEFF, analogously as ORIGEN does (with the same evaluation). E.g. the JEFF3.3 library includes data coming from the TENDL project.
- Ana

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Re: How does Serpent handle missing cross-section libraries during depletion?

Post by froberto » Tue Aug 03, 2021 11:10 pm

I will see what path works best for my proyect.
Thank you Ana for your help.
Roberto

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Jaakko Leppänen
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Re: How does Serpent handle missing cross-section libraries during depletion?

Post by Jaakko Leppänen » Wed Aug 04, 2021 9:45 am

Do you have any decay time after the irradiation? Depending on the data, some of the Co-60 may be in the form of meta-stable Co-60m (half-life 10.5 min). Adding a short inactive time interval at the end of the simulation will allow all short-lived products to decay.

I'm not sure this will affect the comparison to ORIGEN, though.
- Jaakko

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