A military structure located near Plouay in the Morbihan department of Brittany, France, at the given coordinates (47.7638°N, 3.3157°W). The specific designation 'KSB' does not correspond to a widely documented or historically verified site in publicly available sources. The region of Brittany has a long military history, including coastal defenses from various periods, but no confirmed details about this particular location's construction, purpose, or period of use are available in the provided information.
France maintains a significant military infrastructure, including nuclear deterrence forces, but there is no evidence linking this specific coordinate to a known nuclear facility, command post, or other categorized bunker type.