ISO 11320:2011

Overview

ISO 11320:2011 - Nuclear criticality safety - Emergency preparedness and response provides criteria to prepare for and respond to nuclear criticality accidents. It focuses on minimizing life‑threatening consequences at sites that house significant quantities or concentrations of fissile material. The standard complements criticality safety evaluations (see ISO 1709) and distinguishes between ongoing emergency preparedness and the activated emergency response phase.

Key topics and technical requirements

• Scope and applicability: Applies to sites with one or more facilities that might contain significant fissile material. Excludes routine off‑site transport/transit storage and normally excludes operating nuclear power plants or licensed research reactors unless credible external criticality risks exist.
• Management responsibilities: Provide expert staff, establish and maintain an emergency response plan, define immediate evacuation zones and routes, ensure personnel accountability, supply instrumentation and communications, and provide criticality dosimetry and alarm systems (e.g., criticality accident alarm system per ISO 7753).
• Technical staff duties: Identify credible criticality accident locations, evaluate and characterize postulated accidents (including estimated number of fissions and potential recurrence), define evacuation zones, and support training and drills.
• Emergency planning: Develop an emergency response plan tied to documented accident evaluations; include activation criteria, protective actions, medical care, dose estimation, and coordination with on‑site/off‑site emergency organizations.
• Immediate evacuation zone: Establish a clearly marked zone around potential accident locations; consider shielding and other hazards when designing evacuation routes and assembly stations.
• Equipment and monitoring: Provide appropriate protective clothing, respiratory and anticontamination gear, high/low‑range gamma detectors, neutron detectors, personal dosimetry, and assembly‑station monitoring.
• Training and exercises: Conduct classroom training, drills and exercises to verify readiness and to practice evacuation, rescue, re‑entry and stabilization procedures.

Practical applications and users

ISO 11320:2011 is practical for:

• Site managers and facility operators responsible for fissile‑material handling, storage or processing
• Criticality safety engineers and technical staff developing accident evaluations and evacuation criteria
• Radiation protection and emergency planners preparing response plans, dosimetry programs and training
• Regulators and licensing authorities assessing site emergency preparedness and compliance Use cases include design and siting decisions, emergency plan development, training program creation, equipment procurement, and multi‑agency coordination for criticality incidents.

Related standards

• ISO 1709 - Principles of criticality safety in storing, handling and processing fissile materials (used for safety evaluations)
• ISO 7753 - Criticality accident alarm system (referenced for alarm requirements)
• ISO 921 - Nuclear energy - Vocabulary
• ISO 27467 - (Referenced guidance for detailed analysis in evaluations)

Keywords: ISO 11320:2011, nuclear criticality safety, emergency preparedness, emergency response, criticality accident, immediate evacuation zone, criticality dosimetry, ISO 1709, facility emergency plan.