Overview
ISO 6366:2025 - "Non-destructive testing - Leak testing - Radioactive tracer methods for pressured vessels and underground pipelines" specifies radioactive tracer methods for detecting leaks in pressured vessels and in buried pipelines. The standard covers both external and internal detection techniques, safety and radiation protection considerations, equipment requirements, and informative annexes (selection of tracers, leak-rate calculations, activity estimates for heat exchangers, and case studies).
Key topics and technical requirements
- Scope and terminology: Applies to leak testing using radioactive tracers for pressured vessels (e.g., heat exchangers, valves, boilers, tanks) and underground pipelines. Uses terms from ISO 20484.
- Radiation protection: Emphasizes legal and safety responsibilities for ionizing radiation; refers users to IAEA General Safety Requirements and national regulations.
- External detection methods:
- Pulse‑velocity technique - pulse injection upstream and detection downstream; useful for valves and transient signal analysis.
- Response curve technique - commonly used for shell-and-tube heat exchangers; uses detector response curves (and brick/background detectors) to confirm leaks and estimate leak rates.
- Displacement technique - offline method using a tracer reservoir and compensation tank to detect and quantify leaks by monitoring tracer displacement.
- Internal detection methods:
- PIG technique - pipeline inspection gauge carrying detectors and data loggers for internal inspection of buried liquid pipelines.
- Standard equipment requirements: radioisotope tracer, injection systems, radiation detectors, data acquisition, and radiation protection tools (dose meters, contamination monitors, shielding, handling tools, PPE).
- Annex material: Annex A (tracer selection), Annex B (leak-rate calculation), Annex C (activity required for heat exchangers), Annex D (case studies).
Practical applications and users
ISO 6366:2025 is intended for organizations and professionals responsible for leak detection and integrity of pressurized systems:
- Oil & gas and petrochemical operators - online/offline leak testing of process vessels and heat exchangers to reduce downtime and environmental releases.
- Pipeline operators and utilities - locating leaks in buried pipelines using PIG-based internal detection.
- NDT service providers and inspection teams - implementing radioactive tracer techniques (pulse‑velocity, response curve, displacement).
- Radiation safety officers and compliance managers - ensuring safe use of radioactive tracers per legal requirements.
- Civil and process engineers - planning and interpreting tracer-based leak tests for troubleshooting and maintenance.
Benefits include early leak detection, reduced shutdown time, quantified leak rates, and improved environmental protection.
Related standards and references
- Normative reference: ISO 20484 (NDT - Leak testing - Vocabulary).
- Guidance: IAEA General Safety Requirements and applicable national radiation regulations.
- Background/technique references (not normative): technical reports such as TCS 38 referenced in the standard.
Keywords: ISO 6366:2025, radioactive tracer methods, leak testing, pressured vessels, underground pipelines, non-destructive testing, NDT, PIG technique, pulse‑velocity, response curve, displacement technique, radiation protection.