reaktoriydin

Reaktoriydin is the central part of a nuclear reactor where most fission reactions occur. It is located inside the reactor vessel and contains the fuel assemblies, moderators (or reflectors), coolant, and structural components that hold everything in place. The design aims to sustain a controlled nuclear chain reaction while efficiently transferring the generated heat to the primary coolant circuit.

The core comprises fuel assemblies, which consist of fuel rods containing enriched uranium or plutonium. The moderator slows fast neutrons to sustain fission, using materials such as water, heavy water, or graphite. Coolant removes heat from the core and transfers it to heat exchangers. Control rods, made of neutron-absorbing materials like boron, hafnium, or cadmium, can be inserted or withdrawn to adjust reactivity. Structural supports, shielding, and containment surround the core to protect workers and the environment.

The reactor operates in states of criticality: subcritical, critical, or supercritical, depending on reactivity management. In normal operation the system aims for steady power by balancing neutron production and loss. After shutdown, decay heat continues to be produced and must be removed by the cooling system. Redundant safety systems, emergency shutdown mechanisms, and containment structures are designed to prevent accidental releases and limit radiation exposure.

Core design varies by reactor type (for example, light-water, heavy-water, or gas-cooled reactors), affecting neutron spectrum and cooling requirements. Reactor cores are subject to regulatory oversight, licensing, and safety analyses by national authorities and international bodies such as the IAEA.