Corium meaning

In legal practice, corium describes the molten mixture of nuclear fuel and reactor materials produced during a severe nuclear reactor accident (a core meltdown). It is not defined in UK or Irish legislation or case law; it is a technical term used across nuclear safety regulation, environmental permitting, emergency planning and civil nuclear liability. Corium is highly radioactive and thermally destructive. Its potential to breach the reactor pressure vessel or containment and contaminate structures, soil or water underpins legal duties on nuclear site licensees to prevent and mitigate severe accidents, maintain robust safety cases, implement severe accident management and keep risks ALARP. These duties are enforced by the Office for Nuclear Regulation under the Nuclear Installations Act 1965 and site licence conditions. Environmental regulators may require monitoring, remediation, waste characterisation and controlled disposal under radioactive substances permitting regimes. Across England & Wales, Scotland and Northern Ireland, usage is consistent, though regulators differ by jurisdiction. Ireland has no nuclear power reactors, but the term is used in radiological emergency preparedness, cross-border contingency planning and environmental protection. A corium-forming event would typically trigger notification, clean-up, regulatory enforcement and application of civil nuclear liability frameworks.