brændselsstang

A brændselsstang, commonly known as a fuel rod or nuclear fuel rod, is a long, slender tube containing nuclear fuel used in nuclear reactors to produce heat through controlled nuclear fission. These rods are a fundamental component of nuclear reactors, housing pellets of fissile material, typically uranium dioxide (UO₂) or plutonium dioxide (PuO₂), which undergo fission when struck by neutrons.

Brændselsstangene are assembled into bundles called fuel assemblies, which are arranged in a grid pattern within the reactor core. The design and arrangement of these rods influence the reactor’s efficiency, safety, and operational lifespan. The fuel pellets are encased in a cladding material, usually zirconium alloys, which provides structural integrity, prevents radioactive contamination, and facilitates heat transfer to the reactor’s coolant.

During operation, neutrons initiate fission reactions in the fuel pellets, releasing heat and additional neutrons. This chain reaction sustains the process, generating steam to drive turbines for electricity production. Over time, the fissile material depletes, and the rods become less effective, requiring replacement after several years of use. Spent fuel rods, though no longer viable for power generation, remain highly radioactive and require careful storage or reprocessing.

Safety mechanisms, such as control rods inserted between brændselsstangene, regulate the reaction rate by absorbing excess neutrons. In the event of a malfunction, emergency shutdown systems can rapidly withdraw control rods to halt fission. Proper handling and containment of these rods are critical to prevent radiation leaks and ensure reactor safety.