Function of Boron Carbide Control Rods

Boron carbide control rods are movable components used to control the reactivity of the reactor. In other words, the strength of the chain reaction in the reactor can be controlled by the control rods. In addition, the control rods can also be used to control the power distribution of the reactor, avoid the formation of large power peaks, and ensure that the fuel elements do not exceed the design limit.
(1) Compensate for the reactivity loss caused by the temperature effect of the fuel and moderator from hot zero power to full power, as well as the reactivity change caused by power redistribution;
(2) Used to increase or decrease the reactor power, or move the control rods to achieve rapid load tracking, so that the nuclear power plant has the ability to operate under variable conditions;
(3) Under various operating conditions, control rods are used to achieve rapid or emergency shutdown and maintain a certain thermal shutdown reactivity margin;
(4) Compensate for the reactivity change caused by the transient xenon effect during variable conditions, and suppress xenon oscillations by moving the control rods. Therefore, the control rods in the pressurized water reactor are grouped according to different functions, generally divided into shutdown control rod group, power distribution control rod group and power regulation control rod group.