Neutron transport in a moving medium

Hello everyone,

tldr; I am wondering if one may simulate transport in a fast moving medium in OpenMC (how difficult would it be to implement? is implementing this feature planned?).


To give some context, I have so far used OpenMC to test some fairly crazy ideas of subcritical amplifiers of neutron flux. OpenMC was very convenient to use, with excellent documentation, which enabled me to complete this side project in a reasonable amount of time.

Arbitrarily Large Neutron Amplification in Subcritical Nuclear Reactors .

Thank you to all the people who contributed to this project. The result of this first exploration was that these subcritical amplifiers are allowed by the laws of physics and doable with material we can find on earth (which does not mean they are safe or should be made!)

Another idea I have to obtain the same type of subcritical amplification while requiring less complex geometry and nuclides, is to create an asymmetry in neutron current using a fast moving moderator.

My problem

To test this idea, I would need a neutron transport code that allows introducing a quickly moving medium (in my case, very likely D20). We are talking 10 to 100 m/s. Obviously non-relativistic, but it should have a significant impact on neutron flux for thermal neutrons in heavy water.

As far as I know, no neutron transport code currently allows this. The only thing I saw is a custom modification of Geant4 in this paper:

Neutron transport simulation in high speed moving media using Geant4

The implementation is not public as far as I know. Is this type of feature (adding fast moving media) something anyone has considered for openMC? How difficult would it be to implement it (I insist that so far I have only been a user of the code, via its Python API)?

Naturally, I understand that one may not want to add such a feature only to test fringe ideas (although I am happy to discuss said ideas if anyone is interested!). But perhaps that feature could also be used to get more precise neutron flux maps in CANDU reactors (where one would expect very small corrections coming from the flow of heavy water in the pipe, dragging thermal neutrons with it).

Thanks a lot!