function for calculating 0K xs
function for calculating 0K xs

samuelshaner/openmc,walshjon/openmc,bhermanmit/openmc,smharper/openmc,amandalund/openmc,samuelshaner/openmc,lilulu/openmc,samuelshaner/openmc,sxds/opemmc,kellyrowland/openmc,shikhar413/openmc,bhermanmit/openmc,smharper/openmc,paulromano/openmc,mit-crpg/openmc,johnnyliu27/openmc,kellyrowland/openmc,wbinventor/openmc,sxds/opemmc,lilulu/openmc,wbinventor/openmc,liangjg/openmc,amandalund/openmc,nhorelik/openmc,mjlong/openmc,liangjg/openmc,mit-crpg/openmc,shenqicang/openmc,paulromano/openmc,wbinventor/openmc,paulromano/openmc,smharper/openmc,shikhar413/openmc,johnnyliu27/openmc,walshjon/openmc,shikhar413/openmc,amandalund/openmc,mit-crpg/openmc,amandalund/openmc,samuelshaner/openmc,nhorelik/openmc,johnnyliu27/openmc,walshjon/openmc,paulromano/openmc,walshjon/openmc,wbinventor/openmc,mjlong/openmc,liangjg/openmc,johnnyliu27/openmc,lilulu/openmc,liangjg/openmc,shikhar413/openmc,shenqicang/openmc,smharper/openmc,mit-crpg/openmc