Cooling structure and cooling method for control rod drive mechanism and nuclear reactor

A cooling method for a control rod drive mechanism that is placed at an upper portion of a reactor vessel and by which a control rod is inserted into and withdrawn from a reactor core by using a magnetic jack, the cooling method comprising:

• taking cooling air into inside of a housing in which the magnetic jack is housed along an upper side wall of the housing;
• extracting cooling air in the housing to an exhaust duct along an entire periphery of a lower side wall of the housing after cooling the magnetic jack while directing the cooling air downward;
• and
• discharging the cooling air to exterior by an exhaust fan after directing the cooling air upward through the exhaust duct.

A nuclear reactor comprising:

• a reactor vessel;
• a core barrel disposed in the reactor vessel;
• a reactor core disposed in the core barrel;
• a plurality of control rods that controls the reactor core;
• a control rod drive mechanism placed at an upper portion of the reactor vessel and by which the control rods are inserted into and withdrawn from the reactor core;
• and
• a control rod drive mechanism cooling device that cools the control rod drive mechanism with cooling air, wherein
• the nuclear reactor produces electricity by generating steam by heat exchange between nuclear fuel and coolant, and driving a power generating turbine with generated steam, and
• the control rod drive mechanism cooling device includes
• a housing that is fixed to the upper portion of the reactor vessel,
• an air intake unit that takes cooling air into the housing,
• a first exhaust duct that is arranged side by side with the air intake unit in a circumferential direction of the housing, into which cooling air in the housing is suctioned through a first inlet at a lower portion thereof, and that guides the cooling air upward,
• a second exhaust duct that is disposed below the air intake unit, into which cooling air in the housing is suctioned through a second inlet, and that guides the cooling air to the first exhaust duct, and
• a discharging unit that is provided to an upper portion of the housing and discharges cooling air in the first exhaust duct to exterior.