Help to create CFER

User Support
1

Hi everyone,

I’m trying to model the China Experimental Fast Reactor (CEFR) in OpenMC but need some guidance. Specifically:

  • Core layout (fuel assemblies, reflector, etc.)
  • Material compositions (fuel, sodium coolant, etc.)
  • Control systems (rods, zones, etc.)

If anyone has experience with fast reactors in OpenMC or references on CEFR, I’d appreciate your help!

Thanks in advance!

2

Greetings @houssem, welcome to this community!

Usually we would start from a single cell or assembly. CEFR used hexagonal-shaped cell with multiple fuel pins. For each pin in the cell we can model the hole, fuel, cladding, and the sodium coolant like in CANDU example (with different geometries). We should then try to run a cell model (periodic boundary condition).

Then proceed to make a hexagonal lattice, variate the cell (the neutron source, fuel, etc…), and then we got the early simulation for the whole core. For the neutron source, the last time i check openmc doesn’t have a full-support on the spontaneous fission (SF), and neutron source depends on SF, so either we neglect the depletion of the neutron source, or accounted for the transmutation of the neutron source using secluded calculation (ref: https://www.tandfonline.com/doi/full/10.1080/00223131.2021.1974970#d1e2199).

If I’m not wrong, openmc is for steady-state simulation only, and either we neglect SF transmutation or not we still need to define the ‘initial source’ for the problem; each batch of openmc calculation use the previous’ batch result to generate new sources. We can ‘assume’ the initial source like in the tutorial or we built a custom code for the depletion with different initial source for every time step (only do this if you’re not satisfied with merely assuming the initial source).

For your request of guidance, I find this document quite helpful to give the impression of the internal of CEFR: https://conferences.iaea.org/event/218/contributions/18929/attachments/13010/20083/104_SpSessionIAEA_Huo.pdf

Good luck with your research!

Best regards,
Chris.

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3

Thank you for your detailed message and the useful references! I am particularly interested in finding simulations related to the document you provided. Specifically, I am looking for examples of fuel assembly modeling or control rod configurations. If you have any additional resources, example cases, or guidance on how to set up such simulations in OpenMC (or another suitable tool), I would greatly appreciate it.

Any insights on how to handle neutron source modeling, especially considering the limitations of OpenMC with spontaneous fission, would also be very helpful.

Looking forward to your recommendations!

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