removed catenation of element expand atomic amount
removed catenation of element expand atomic amount

samuelshaner/openmc,smharper/openmc,johnnyliu27/openmc,liangjg/openmc,liangjg/openmc,paulromano/openmc,samuelshaner/openmc,paulromano/openmc,mit-crpg/openmc,johnnyliu27/openmc,wbinventor/openmc,wbinventor/openmc,smharper/openmc,shikhar413/openmc,johnnyliu27/openmc,shikhar413/openmc,shikhar413/openmc,samuelshaner/openmc,smharper/openmc,amandalund/openmc,walshjon/openmc,mit-crpg/openmc,walshjon/openmc,amandalund/openmc,walshjon/openmc,paulromano/openmc,wbinventor/openmc,amandalund/openmc,mit-crpg/openmc,mit-crpg/openmc,liangjg/openmc,shikhar413/openmc,samuelshaner/openmc,amandalund/openmc,wbinventor/openmc,walshjon/openmc,liangjg/openmc,bhermanmit/openmc,paulromano/openmc,bhermanmit/openmc,smharper/openmc,johnnyliu27/openmc