Sailors prepare a French Rubis-class submarine at the Toulon naval base in southern France, Monday, April 15, 2024. The nuclear powered submarine will be guarding France's Charles de Gaulle aircraft carrier during training exercises dubbed Neptune Strike in the Mediterranean with the 32-nation NATO military alliance. (AP Photo/Daniel Cole)
The wall of a French Rubis-class submarine is pictured at the Toulon naval base in southern France, Monday, April 15, 2024. The nuclear powered submarine will be guarding France's Charles de Gaulle aircraft carrier during training exercises dubbed Neptune Strike in the Mediterranean with the 32-nation NATO military alliance. (AP Photo/Daniel Cole)
A sailor prepares a French Rubis-class submarine at the Toulon naval base in southern France, Monday, April 15, 2024. The nuclear powered submarine will be guarding France's Charles de Gaulle aircraft carrier during training exercises dubbed Neptune Strike in the Mediterranean with the 32-nation NATO military alliance. (AP Photo/Daniel Cole)
A French Rubis-class submarine is pictured at the Toulon naval base in southern France, Monday, April 15, 2024. The nuclear powered submarine will be guarding France's Charles de Gaulle aircraft carrier during training exercises dubbed Neptune Strike in the Mediterranean with the 32-nation NATO military alliance. (AP Photo/Daniel Cole)
A sailor prepares a French Rubis-class submarine at the Toulon naval base in southern France, Monday, April 15, 2024. The nuclear powered submarine will be guarding France's Charles de Gaulle aircraft carrier during training exercises dubbed Neptune Strike in the Mediterranean with the 32-nation NATO military alliance. (AP Photo/Daniel Cole)
A sailor descends into a French Rubis-class submarine at the Toulon naval base in southern France, Monday, April 15, 2024. The nuclear powered submarine will be guarding France's Charles de Gaulle aircraft carrier during training exercises dubbed Neptune Strike in the Mediterranean with the 32-nation NATO military alliance. (AP Photo/Daniel Cole)
Sailors prepare a French Rubis-class nuclear powered submarine to participare in NATO's upcoming Neptune Strike training exercise at the Toulon naval base in southern France, Monday, April 15, 2024. (AP Photo/Daniel Cole)
Equipment and food to be stored away is pictured on a French Rubis-class submarine at the Toulon naval base in southern France, Monday, April 15, 2024. The nuclear powered submarine will be guarding France's Charles de Gaulle aircraft carrier during training exercises dubbed Neptune Strike in the Mediterranean with the 32-nation NATO military alliance. (AP Photo/Daniel Cole)
Sailors prepare a French Rubis-class submarine at the Toulon naval base in southern France, Monday, April 15, 2024. The nuclear powered submarine will be guarding France's Charles de Gaulle aircraft carrier during training exercises dubbed Neptune Strike in the Mediterranean with the 32-nation NATO military alliance. (AP Photo/Daniel Cole)
Sailors prepare a French Rubis-class submarine at the Toulon naval base in southern France, Monday, April 15, 2024. The nuclear powered submarine will be guarding France's Charles de Gaulle aircraft carrier during training exercises dubbed Neptune Strike in the Mediterranean with the 32-nation NATO military alliance. (AP Photo/Daniel Cole)
Sailors prepare a French Rubis-class submarine at the Toulon naval base in southern France, Monday, April 15, 2024. The nuclear powered submarine will be guarding France's Charles de Gaulle aircraft carrier during training exercises dubbed Neptune Strike in the Mediterranean with the 32-nation NATO military alliance. (AP Photo/Daniel Cole)
A sailor prepares a French Rubis-class submarine at the Toulon naval base in southern France, Monday, April 15, 2024. The nuclear powered submarine will be guarding France's Charles de Gaulle aircraft carrier during training exercises dubbed Neptune Strike in the Mediterranean with the 32-nation NATO military alliance. (AP Photo/Daniel Cole)
A poster is pictured on a French Rubis-class submarine at the Toulon naval base in southern France, Monday, April 15, 2024. The nuclear powered submarine will be guarding France's Charles de Gaulle aircraft carrier during training exercises dubbed Neptune Strike in the Mediterranean with the 32-nation NATO military alliance. (AP Photo/Daniel Cole)
A rope secures a French Rubis-class submarine at the Toulon naval base in southern France, Monday, April 15, 2024. The nuclear powered submarine will be guarding France's Charles de Gaulle aircraft carrier during training exercises dubbed Neptune Strike in the Mediterranean with the 32-nation NATO military alliance. (AP Photo/Daniel Cole)
A sailor disembarks a French Rubis-class submarine at the Toulon naval base in southern France, Monday, April 15, 2024. The nuclear powered submarine will be guarding France's Charles de Gaulle aircraft carrier during training exercises dubbed Neptune Strike in the Mediterranean with the 32-nation NATO military alliance. (AP Photo/Daniel Cole)
Sailors prepare a French Rubis-class submarine at the Toulon naval base in southern France, Monday, April 15, 2024. The nuclear powered submarine will be guarding France's Charles de Gaulle aircraft carrier during training exercises dubbed Neptune Strike in the Mediterranean with the 32-nation NATO military alliance. (AP Photo/Daniel Cole)