Hi,
I would like to know how SERPENT 2 goes about its calculation of the sixfactor formula. Are there any approximations or assumptions that allow for the calculation of these parameters?
And since the sixfactor formula is typically for thermal systems, how does SERPENT make this calculation for fast systems?
Thanks
Sixfactor formula

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Re: Sixfactor formula
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 energygroups 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 sixfactor formula (utilization factor FF_F, resonance escape probability FF_P, kinf FF_KINF and keff FF_KEFF). The parameters are calculated using analog estimates.
The sixfactor formula is an approximation that applies to the thermal spectrum. Serpent does not make any consideration to extrapolate it to the fast spectrum.
The sixfactor formula is an approximation that applies to the thermal spectrum. Serpent does not make any consideration to extrapolate it to the fast spectrum.
 Ana