def get_bu_sec_conv_factor(vol, ihm):
    """Computes the factor that converts seconds into burnup units (MWd/kg) from a given volume and a Initial Heavy Metal mass (IHM).

    Parameters
    ----------
    vol: float
        Volume of the region
    ihm: float
        Initial Heavy Metal mass of the region
    """
    bu_sec_conv_factor = vol*1e-3/(ihm*24*3600) # Unit in L/g

    return bu_sec_conv_factor