Use r.core.axialMesh() for uniform mesh.

[mgjarrett]

Description

When making a uniform mesh assembly in the UniformMeshConverter, the freshly minted assembly does not have any submesh (i.e., b.p.axMesh = 1).

armi/armi/reactor/converters/uniformMesh.py

Line 380 in bc3cf47

block.p.axMesh = 1

Creating a uniform mesh assembly with the refAssem's block mesh (r.core.refAssem.getAxialMesh()) poses problems if some blocks in the refAssem have a submesh (i.e., b.p.axMesh > 1), because the uniform mesh assembly will not have a submesh. r.core.p.axialMesh() contains the computational neutronics mesh, which has all of the mesh subdivisions; this is the mesh that should be used for makeAssemWithUniformMesh().

---

Checklist

• This PR has only one purpose or idea.
• Tests have been added/updated to verify that the new/changed code works.

• The code style follows good practices.
• The commit message(s) follow good practices.

• The release notes (location doc/release/0.X.rst) are up-to-date with any bug fixes or new features.
• The documentation is still up-to-date in the doc folder.
• The dependencies are still up-to-date in setup.py.

[mgjarrett]

I ran the tests locally and they passed, so... I don't know? The 3.7, 3.8, 3.9, and 3.10 unit tests all pass, but the "ARMI Windows tests" fails. I can't think of anything changed here that would be affecting the failing test.

[john-science]

@mgjarrett I would guess that the issue is a race condition somewhere in test_assemblies.py or textProcessors.py.

    File "D:\a\armi\armi\armi\reactor\tests\test_assemblies.py", line 589, in _setup_blueprints
...
    File "D:\a\armi\armi\armi\utils\textProcessors.py", line 106, in _processIncludes
      raise ValueError(
  ValueError: The !included file, `refSmallSfpGrid.yaml` does not exist from D:\a\armi\armi\armi\tests\detailedAxialExpansion!

My assumption here is if you ran the test again, the bug would not appear.

I'll be honest, I've run the ARMI unit tests thousands of times, and not seen this one. So if I see it a second time, I'll have to fix it. But I'm hoping this is a one-off bug with the Windows file system.

Probably, your next commit will fix this, because it will force the tests to re-run.