cloudmc graveyard definition

[sjcrs]

Per correspondence with Jon Shimwell,

"By the way we noticed this section of code with the hard code 10,000cm radius sphere"

    univ = openmc.DAGMCUniverse(
        filename='geometryInput-dagmcFile.dagmc.h5m',
        auto_geom_ids=True,
    )
    graveyard = openmc.Sphere(r=10000, boundary_type="vacuum")
    root = openmc.Universe()
    root.add_cells([openmc.Cell(region=-graveyard, fill=univ)])

could be rewritten as this to give a more compact graveyard and perhaps less zooming in for the user when visualizing

root = openmc.DAGMCUniverse(
    filename='geometryInput-dagmcFile.dagmc.h5m',
    auto_geom_ids=True
).bounded_universe()