Kinetics parameters using Iterated Fission Probability

[JoffreyDorville]

Description

Calculation of adjoint-weighted kinetics parameters (effective generation time and effective delayed neutron fraction) using the Iterated Fission Probability (IFP) method.

This implementation uses the same approach as the IFP implementation in Serpent 2 documented in [1].

To generate results for both effective generation time and effective delayed neutron fraction, IFP settings need to be set:

settings.iterated_fission_probability = {
    "parameter": "both",
    "n_generation": 5
}

and a specific tally has to be set:

tally = openmc.Tally(name="ifp-scores")
tally.scores = [
    "ifp-time-numerator",
    "ifp-beta-numerator",
    "ifp-denominator"
]

Testing is still in progress. I will update the draft to PR once I have finished the remaining tests.

References

[1] J. Leppänen, M. Aufiero, E. Fridman, R. Rachamin, and S. van der Marck, “Calculation of effective point kinetics parameters in the Serpent 2 Monte Carlo code,” Annals of Nuclear Energy, vol. 65, pp. 272–279, Mar. 2014, doi:10.1016/j.anucene.2013.10.032

Checklist

• I have performed a self-review of my own code
• I have run clang-format (version 15) on any C++ source files (if applicable)
• I have followed the style guidelines for Python source files (if applicable)
• I have made corresponding changes to the documentation (if applicable)
• I have added tests that prove my fix is effective or that my feature works (if applicable)

[zhangzeqin1997]

I have tested this feature, and everything works well at the moment. I would like to inquire if there are any plans to add output for the individual delayed neutron group fractions and decay constants, similar to how it is done in MCNP.