add draft description to methodology on white boundary condition
add draft description to methodology on white boundary condition

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