Six-factor formula

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kcogujiu
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Six-factor formula

Post by kcogujiu » Tue Jun 15, 2021 8:13 pm

Hi,
I would like to know how SERPENT 2 goes about its calculation of the six-factor formula. Are there any approximations or assumptions that allow for the calculation of these parameters?

And since the six-factor formula is typically for thermal systems, how does SERPENT make this calculation for fast systems?

Thanks

Ana Jambrina
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Re: Six-factor formula

Post by Ana Jambrina » Wed Jun 16, 2021 2:41 pm

Fission (absorption, FF_ABS, and production, FF_ETA and FF_EPSILON), capture (absorption, FF_ABS) and leakage (leak rates, FF_LT and FF_LF) are scored (total, thermal/fast region: two energy-groups are considered, E < 0.625 eV and E >= 0.625 eV) in ‘scorefission.c’, ‘scorecapture.c’ and ‘leak.c’ routines, respectively. In ‘collectresults.c’, you can follow the sequence that evaluates/scores the remaining parameters part of/related to the six-factor formula (utilization factor FF_F, resonance escape probability FF_P, k-inf FF_KINF and k-eff FF_KEFF). The parameters are calculated using analog estimates.

The six-factor formula is an approximation that applies to the thermal spectrum. Serpent does not make any consideration to extrapolate it to the fast spectrum.
- Ana

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