Dual shut-off valve

A nuclear reactor disposed with a containment structure, comprising:

• a reactor core disposed within a pressure vessel;
• a primary coolant inlet line passing through both the pressure vessel and the containment structure;
• and
• a first dual shut-off valve both disposed within the containment structure and in fluid communication with the primary coolant inlet line, comprising:
• a valve body defining an interior cavity and a flow tube passing therethrough;
• an outer cylinder including a body portion defining an interior cavity and a through hole passing therethrough, the outer cylinder being rotatably disposed within the interior cavity of the valve body;
• and
• an inner cylinder including a body portion defining a through hole passing therethrough, the inner cylinder being rotatably disposed within the interior cavity of the outer cylinder, wherein the inner cylinder and the outer cylinder are both rotatable between a first position in which a longitudinal center axis of the through hole of the outer cylinder and a longitudinal center axis of the inner cylinder are aligned with a longitudinal center axis of the flow tube, and a second position in which the longitudinal center axes of the through holes of the outer cylinder and the inner cylinder are not aligned with the longitudinal center axis to the flow tube.