ISO 23133:2021

Overview

ISO 23133:2021 - Nuclear criticality safety: Nuclear criticality safety training for operations specifies minimum training requirements for operations staff, operations supervisors, and management working in areas, processes or facilities that contain fissile material and require a nuclear criticality safety assessment (as defined in ISO 1709). The standard focuses on high‑level, practical training to maintain nuclear criticality safety during routine operations and to prepare for/mitigate potential criticality events. It does not cover transport of fissile material outside nuclear establishment boundaries.

Key topics and requirements

• Target audience: operations staff, operations supervisors, and management - with different depth and scope of training for each role.
• Training program requirement: organizations must include an operations nuclear criticality safety training program within their overall nuclear criticality safety program.
• Principal training objectives: understanding the nature and severity of a criticality accident; mechanisms and controls to prevent criticality; awareness that all operational roles can affect criticality safety; workplace‑specific criticality considerations; and the role of emergency preparedness and response.
• Role definitions: clear responsibilities for operations staff, supervisors, management, nuclear criticality safety staff, training coordinators, and criticality trainers.
• Before‑work requirement: sufficient training must be completed and confirmed effective before starting work that may present a criticality hazard. On‑the‑job training may be allowed only under direct supervision.
• Training lifecycle: includes content design (Clause 6), delivery methods (Clause 7), evaluation and testing (Clause 8), maintenance/refresher training (Clause 9), and record keeping (Clause 10).
• Safety focus: emphasizes understanding reasons behind controls to reduce procedural deviations that have contributed to past criticality accidents.

Practical applications - who uses this standard

• Nuclear facility operators and production staff who handle or process fissile material.
• Shift leaders, operations supervisors and managers responsible for safety decisions and program definition.
• Nuclear criticality safety staff, trainers and training coordinators designing and delivering curriculum.
• Regulatory bodies, auditors and contractors who need to verify training adequacy for criticality risk controls.
• Facilities implementing or updating their nuclear criticality safety training program to align with international best practice.

Related standards

• ISO 1709 - nuclear criticality safety assessment (defines when assessment is required).
• ISO 11320 - emergency preparedness and response (more specific provisions for criticality emergency training).
• ISO 14943 - referenced for supervisory responsibilities.

ISO 23133:2021 is essential for organizations seeking a structured, auditable approach to nuclear criticality safety training, improving operational competence and reducing human‑error risks in fissile material handling.