Precursor group sampling failed

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orca.blu
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Joined: Wed Apr 20, 2011 1:39 pm

Precursor group sampling failed

Post by orca.blu » Wed Jan 02, 2013 6:48 pm

Hi, I found these warning messages in the log file of my simulations
[...]

***** Wed Jan 2 15:23:20 2013 (seed = 1357139819, MPI task = 2)
Warning message from function SamplePrecursorGroup:

Precursor group sampling failed (92235.03c, mt 18, E = 6.277916E-01)

------------------------------------------------------------

Serpent 2.1.10 -- Static criticality source simulation

[...]
It seems to be something rare:
it happens at most twice in simulations with 500e6 neutron histories...

I believe it has no impact at all, right?
Manuele Aufiero
LPSC/IN2P3/CNRS Grenoble

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Jaakko Leppänen
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Re: Precursor group sampling failed

Post by Jaakko Leppänen » Sat Jan 05, 2013 3:35 pm

It's most likely a numerical problem in the delayed neutron precursor data (sum of precursor group fractions is slightly below 1). If you get this warning message only once, it shouldn't matter. Which data library are you using?
- Jaakko

orca.blu
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Re: Precursor group sampling failed

Post by orca.blu » Sat Jan 05, 2013 7:57 pm

Ok thank you.
Jeff 3.1 (the one provided with serpent 1)
Manuele Aufiero
LPSC/IN2P3/CNRS Grenoble

novako
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Re: Precursor group sampling failed

Post by novako » Thu Mar 26, 2020 12:32 pm

Hi,
I do experience the same warning. I experienced this during simulation of 5e9 neutrons 5 times. All cases were on U239, see lower.

Precursor group sampling failed (92235.00c, mt 18, E = 1.208597E-08)
Precursor group sampling failed (92235.00c, mt 18, E = 1.179692E-08)
Precursor group sampling failed (92235.00c, mt 18, E = 1.107475E-07)
Precursor group sampling failed (92235.00c, mt 18, E = 2.894528E-08)
Precursor group sampling failed (92235.00c, mt 18, E = 3.356145E-08)

I use JEFF3.3 Library.

Is this number of warning high enough to worry or rare enough to keep calm :)?
Or should we do something with libraries?
Thank you
Ondrej

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Jaakko Leppänen
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Re: Precursor group sampling failed

Post by Jaakko Leppänen » Fri Mar 27, 2020 10:32 am

With that many histories you should get something like 10 million delayed neutrons sampled. 5 failures doesn't seem that much.
- Jaakko

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