emergency button AZ-5

the night foreman Aleksandr Akimov, under the orders of Anatoli Diatlov, the deputy chief engineer, triggers the emergency stop by pressing the AZ-5 key.

The control rods were lowered, with no great consequence: in fact, the reactor is already much too hot, which deformed the channels intended for the control rods; these only descended to 1.50 m instead of the normal 7 m. In addition, due to a design defect in the RBMK reactor shutdown system, the ends of the control rods made of boron (material that absorbs and slows down fission) are made of graphite, which on the contrary accelerates the fission reaction at the beginning of the insertion of the rods.

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