Initial enrichment option in Element.expand
Initial enrichment option in Element.expand

-> Implementation supports only wt% enrichment
-> Multiple unnecessary conversions from at% to wt% can happen
-> Can produce -ve fractions if enrichment > 100

amandalund/openmc,amandalund/openmc,paulromano/openmc,shikhar413/openmc,mit-crpg/openmc,walshjon/openmc,shikhar413/openmc,smharper/openmc,liangjg/openmc,mit-crpg/openmc,mit-crpg/openmc,paulromano/openmc,liangjg/openmc,liangjg/openmc,paulromano/openmc,shikhar413/openmc,shikhar413/openmc,mit-crpg/openmc,walshjon/openmc,walshjon/openmc,paulromano/openmc,liangjg/openmc,smharper/openmc,amandalund/openmc,walshjon/openmc,amandalund/openmc,smharper/openmc,smharper/openmc