Ignore negative volume components in mass-weighted averaging

[mgjarrett]

What is the change? Why is it being made?

Change: Ignore any component with negative area when computing a mass-weighted average temperature and composition for a set of components.

Background: When building a representative block in the CrossSectionGroupManager for a cross section type with the option averageByComponent: true, it is necessary to compute an average temperature and composition across all blocks in the BlockCollection for each component in the representative block. In normal circumstances, a mass-weighted average is used. However, there are some situations where a component can have negative area/volume and thus negative mass. If some components in the BlockCollection have positive mass and others have negative mass, the mass-weighted average temperature of the components can be extremely different than a non-weighted average. In some cases, the resulting temperature could be outside the bounds of defined material properties, which could cause a run to crash.

SCR Information

Change Type: fixes

One-Sentence Rationale: This addresses a corner case bug that could cause ARMI apps to crash when there are negative-volume components present.

One-line Impact on Requirements: NA

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Checklist

• This PR has only one purpose or idea.
• Tests have been added/updated to verify any new/changed code.
• The documentation is still up-to-date in the doc folder.
• The code style follows good practices.
• The dependencies are still up-to-date in pyproject.toml.