We investigate, in the paradigm of open quantum systems, the dynamics of quantum coherence of a circularly accelerated atom coupled to a bath of vacuum fluctuating massless scalar field in a spacetime with a reflecting boundary. The master equation that governs the system evolution is derived. It is found that the quantum coherence diminishes to zero with increasing centripetal acceleration and evolution time in the case without a boundary. However, the presence of a boundary will modify the quantum fluctuations of the scalar field, which results in the enhancement of quantum coherence near the boundary compared with that for the unbounded case. Particularly, when the atom is very close to the boundary, although the atom still interacts with the environment, it behaves as if it were a closed system as a consequence of the presence of the boundary, and the quantum coherence can be shielded from the effect of the vacuum fluctuating scalar field.
PACS numbers: 03.65.Yz, 03.67.Mn, 03.65.Ta