Decommissioned

Decommissioned is an adjective or verb meaning formally withdrawn from service or operation and deprived of its status as an active asset. A facility, vessel, vehicle, or system is decommissioned after a decision by the responsible organization following safety, regulatory, and financial considerations. The term contrasts with retirement or scrapping, and implies a planned, controlled ending rather than abrupt shutdown.

Common targets include military ships and aircraft no longer in use, civilian nuclear reactors and other hazardous facilities, oil platforms, and large industrial plants. Decommissioning is distinct from maintenance shutdowns or temporary layups.

Process: decommissioning typically begins with a decommissioning plan approved by regulators. It may include defueling or removing hazardous materials, decontamination, dismantling, environmental remediation, and waste management. Final disposition ranges from long-term storage to recycling, sale for reuse, or demolition. In some cases, the site is repurposed for new facilities or designated as a museum or heritage site.

Regulation and practice vary by country but share core principles: protecting public safety and the environment, documenting activities, and ensuring long-term accountability. International guidelines from bodies such as the IAEA influence national rules, especially for nuclear facilities.

Examples: nuclear decommissioning programs at research reactors and power plants, the ongoing work at Fukushima Daiichi, and the retirement and dismantling of old naval ships and offshore platforms illustrate the range of approaches and timelines.