ISO 26802:2010

ISO 26802:2010 - Overview

ISO 26802:2010 defines criteria for the design and operation of containment and ventilation systems for nuclear reactors. It applies to nuclear power plants with a secondary confinement system (per IAEA recommendations) and to research reactors where accidental high‑pressure or high‑temperature transients can challenge containment integrity. The standard complements ISO 17873 (ventilation for other nuclear installations) and references ISO 10648‑2 and ICRP 103.

Key technical topics and requirements

ISO 26802:2010 covers the full lifecycle of containment and ventilation systems with emphasis on safety and operational robustness. Major technical topics include:

• Ventilation system functions - required airflows, dynamic confinement, air exchange rates, and air conditioning for containment envelopes.
• System architecture - ventilation of volumes inside primary containment envelopes, within secondary confinement, and external volumes; plus miscellaneous non‑connected ventilation systems.
• Safety and risk assessment - general safety principles, procedures for assessing risks during design‑basis and beyond‑design‑basis (including severe) accidents, and consideration of external hazards.
• Design requirements - confinement of radioactive material, filtration systems (decontamination factors, filter types), and reactor‑specific design considerations.
• Risk management - control of combustible gases, ambient condition management, prevention of heat/gas/toxic vapour releases, deposition in ducts, and fire hazards.
• Operation, maintenance and testing - organizational arrangements, operating procedures, test procedures, maintenance schedules, monitoring, and leaktightness checks.
• Control and instrumentation - control strategies, instrumentation needs, and alarm requirements for safe operation of ventilation and containment systems.
• Informative annexes - examples of radioactive products, confinement concepts, safety classifications, ventilation configurations, filter requirements, load cases and leaktightness values.

Practical applications and intended users

ISO 26802:2010 is intended for professionals responsible for nuclear safety and facility design, including:

• Nuclear plant designers and systems engineers specifying containment and ventilation architecture.
• Reactor safety analysts performing risk assessments for design‑basis and severe accidents.
• Plant operators and maintenance teams implementing operation, testing and monitoring programs.
• Regulatory bodies and auditors evaluating compliance with containment/ventilation requirements.
• Consultants and contractors involved in filtration, control systems and HVAC design for nuclear facilities.

Related standards and guidance

• ISO 17873 - ventilation for other nuclear installations
• ISO 10648‑2 - containment enclosure leak‑tightness classification
• ICRP 103 and IAEA recommendations - radiological protection and secondary confinement guidance

ISO 26802:2010 is essential when specifying safe, compliant containment and ventilation systems for nuclear reactors, helping minimize radioactive release risk and ensuring reliable operation under normal and accidental conditions.