LOCA meaning

In legal and regulatory practice, LOCA means a loss‑of‑coolant accident in a nuclear reactor: a breach or failure in the primary circuit that rapidly depletes coolant and, if not controlled, can cause reactor core damage and potential radioactive release. The term is descriptive rather than defined in legislation or case law, but it is widely used in nuclear safety cases, licensing, enforcement and contracting. In the UK, LOCA is a standard design‑basis accident scenario assessed in safety submissions to the Office for Nuclear Regulation (ONR). Site licence conditions and ONR’s Safety Assessment Principles expect robust prevention and mitigation, including an Emergency Core Cooling System (eccs), shutdown and containment features, and demonstrable emergency preparedness. Off‑site planning duties arise under the Radiation (Emergency Preparedness and Public Information) Regulations 2019 (REPPIR). LOCA analysis also informs insurance, indemnities and liability allocation under the Nuclear Installations Act 1965 regime. Usage and regulatory expectations are broadly consistent across England & Wales, Scotland and Northern Ireland (with equivalent emergency planning frameworks). In Ireland, while there are no power reactors, LOCA is recognised in radiological emergency planning and cross‑border risk assessment overseen by the Environmental Protection Agency, aligning with international nuclear safety standards.