safety rod

In nuclear physics, a safety rod is a crucial component used to control nuclear fission reactions within a nuclear reactor. These rods are made of neutron-absorbing materials, such as boron carbide. Their primary function is to shut down the reactor, either during scheduled maintenance or in emergency situations.12

Safety rods are designed to be fail-safe, meaning they will automatically insert into the reactor core by gravity or another safe mechanism if there is a mechanical failure. This rapid insertion, often referred to as a "scram," quickly stops the chain reaction and brings the reactor to a subcritical state, preventing a meltdown. They are withdrawn before fuel is loaded and reinserted to ensure safe operation.234