Material.add_elements_from_formula ignores enrichment parameter for U

[cgarta]

Defining a material using add_elements_from_formula method with enrichment in U235 doesn’t work.
uo2.add_elements_from_formula('UO2', enrichment=4.0) and uo2.add_elements_from_formula('UO2') both give the same compositions.

[shimwell]

I realize this is not a solution but it gives a little more detail if you pass "enrichment_target=U" as an argument. It looks like it is trying to enrich U using the normal enrichment strategy for elements with just two isotopes.

This is due to the logic here

U is enriched differently to elements with just two isotopes so I guess this is why I missed this earlier. Sorry about that.

Just out of interest does this work for you.

mat1 = openmc.Material()
mat1.add_element('U', percent=1, enrichment=4, enrichment_target='U')

Do people think that Uranium should be enriched when it is specified as a target? Currently it needs to be enrichment_target=None to enrich Uranium which is different to the other elements

I'm wonder if the thing to fix is in openmc/materials.py add_elements function

I'm wondering if we should change this line so that it is true even if statement when the enrichment_target is set to None or to 'U'

[drewejohnson]

This was closed in #1605