[OceanNuclear]

Description

Calculates the neutron flux profile in the first wall and blanket, using an extremely simplified diffusion-based model of an infinite slab sandwich.

Reason for choosing this model

It's better than not having a neutronics model.
It's also very simplified, so it can be calculated on the fly, without installing any deterministic neutron transport codes as dependency.

Checklist

I confirm that I have completed the following checks:

• My changes follow the PROCESS style guide
• I have justified any large differences in the regression tests caused by this pull request in the comments.
• I have added new tests where appropriate for the changes I have made.
• If I have had to change any existing unit or integration tests, I have justified this change in the pull request comments.
• If I have made documentation changes, I have checked they render correctly.
• I have added documentation for my change, if appropriate.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 54.84222% with 415 lines in your changes missing coverage. Please review.
✅ Project coverage is 50.39%. Comparing base (0b69cfc) to head (8502e7f).

Files with missing lines	Patch %	Lines
process/models/neutronics/base.py	47.40%	284 Missing ⚠️
process/models/neutronics/data.py	65.06%	131 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3653      +/-   ##
==========================================
+ Coverage   50.26%   50.39%   +0.13%     
==========================================
  Files         181      184       +3     
  Lines       30629    31548     +919     
==========================================
+ Hits        15395    15899     +504     
- Misses      15234    15649     +415     

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[OceanNuclear]

The current state of this branch is:

• 1-group 2-layer model is written
• 1-group 2-layer model is fully tested (regression & unit tests)
• Multi-group model & >2-layer model is written
• Multi-group model & >2-layer model is tested
• incorporated real data
• Wrote function that accepts collapsed cross-section data (The downloading and collapsing of nuclear data has to be done by the user using a class that inherits from ENDFRecord.)
• Plotting is already available, example 1-group 2-layer model:

• Plotting is tested

[OceanNuclear]

@chris-ashe In the new folder structure, would you prefer the neutronics.py and neutronics_data.py to live in model/ or core/?

[je-cook]

I'm not sure descriptors is the right way to go. Most descriptor stuff I've written I have eventually rewritten without descriptors because I found a better way.

On the atomic data is there any reason we cant use something like periodictable which we use in elsewhere.

[OceanNuclear]

Happy to hear out examples of where descriptors were removed and see if I can implement anything similar. So far I'm unaware of any other ways of writing the code that wouldn't make it even more spaghetti: the @summarize_values decorator is doing a lot of heavy lifting and cutting the amount of code that I have to write down by half.

[je-cook]

Great, need to have a think but will let you know

[OceanNuclear]

periodictable sounds good, thanks for the suggestion, I'll likely replace the atomic_data.json with it, and possibly cutting down the size of the PR as a result.

I haven't figured out yet the right way of getting the abundance values in periodictable (in the same format as written at the top of the atomic_data.json), but I'm sure I'll find it eventually.