Commissariat a L'energie Atomique

Yves Bergamaschi

Jean Geffroy

Jean-Marie Seiler

Francois Balard

Imre Szabo

Gian L Fiorini

The control rod (4) carrying absorbing elements (5) contains an operating rod (37) forced upwards by washers (38) and projecting by a push button end (52). When it is decided to uncouple the absorbing elements, the control rod (4) is raised, so that the teeth (62) of ratchets (56) opened out beforehand weigh on the push button (52), lower the operating rod (37) and enable coupling balls (33) to enter a groove (35) on the bottom of the rod, which detaches the pommel (18) carrying the absorbing elements (5). Application to pressurized water nuclear reactors.

Device for uncoupling a control rod from an absorbing element for a

The device makes it possible to automatically disconnect an absorber fuel rod cluster (6) from its control rod (5) when the pressure and/or temperature within the vessel of the reactor have dropped below a certain value. Use is mainly made of a thermal module (35) located between the attachment head (37) and the locking member (32) in order to form a mobile assembly optionally completed by a barometric module placed beneath the locking member (32). Application to pressurized water nuclear reactors.

Device for the automatic disconnection of a control rod and a nuclear

In order to ensure the recovery and confinement of the core of a nuclear reactor, such as a pressurized water reactor, in the case of a serious accident leading to its melting or meltdown, it is proposed that below the reactor vessel (16) be placed a receptacle (20) able to evacuate the water accumulated below the vessel (16) in the initial phase of the accident and then collect the molten core debris. The water automatically flows through overflow and siphon devices (46, 50) into a cooling space (40) located below the receptacle. If the meltdown of the core (18) has been detected, the water contained in tanks (56) flows by gravity into the space (40), so as to entirely immerse the containers (26) placed in said space. The molten core traversing the bottom of the vessel (16) flows into the receptacle (20) and then into containers (26) via meltable plugs (32) and a natural convection flow is established between the tanks (56) and the space (40) in order to ensure cooling. Fall absorbers or dampers (76) are placed in the receptacle (20) for the case where the bottom of the vessel (16) drops in a single block.

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Aix en Provence, France

Yves Bergamaschi