Yes
The reactor building is designed to mechanically withstand the pressure of the water. Even in a situation of this kind, it would remain watertight.
The rise in water levels caused by the breach of the Monteynard dam would not therefore affect the building’s structure. On the other hand, it would lead to a total loss of electrical power, as the two 20 kV substations and the two emergency diesel generators would be under water.
The loss of these power supplies would automatically trigger the shutdown of the reactor by safety rod drop. Cooling would be adequately provided by simple natural convection using the water in the reactor pool.