Refuge is an Achievement for Halo 3 on the Xbox 360.
It is earned when one finishes the campaign mission The Ark on the Normal, Heroic, or Legendary difficulties, and gives 30 Gamerpoints to the player.
It is represented by a blue plate with a roman numeral "VI" on it.
Note: You must finish the level completely through without quiting, or it won't count.
References
All achievements in Halo 3.