Kritikalitetssäkring

Kritikalitetssäkring is a Swedish term that translates to "criticality assurance" or "criticality safety" in English. It refers to a set of principles, procedures, and practices designed to prevent accidental criticality in nuclear facilities, particularly those involving fissile materials. Accidental criticality occurs when a self-sustaining nuclear chain reaction is initiated unintentionally, releasing a significant amount of radiation and energy.

The core objective of kritikalitetssäkring is to maintain fissile materials in a subcritical state under all foreseeable conditions, including normal operation, maintenance, storage, and accident scenarios. This is achieved through careful control of the amount of fissile material, its concentration, geometry, and the presence of neutron-absorbing materials.

Key elements of kritikalitetssäkring include administrative controls, such as defined operating procedures, material handling limits, and personnel training, as well as engineered controls. Engineered controls can include physical barriers, neutron-absorbing materials (like boron or cadmium) incorporated into equipment or storage containers, and control rods that can be inserted into a reactor core to absorb neutrons and stop the chain reaction.

For facilities handling enriched uranium or plutonium, robust kritikalitetssäkring measures are essential to prevent the accumulation of fissile material in configurations that could lead to a criticality accident. This involves rigorous analysis of potential scenarios, including errors in handling, storage, or processing, and implementing safety margins to ensure subcriticality is maintained. The design and operation of nuclear reactors, fuel reprocessing plants, and waste storage facilities all incorporate specific kritikalitetssäkring protocols to ensure public and worker safety.