Radiological Protection in Customs and Freight Operations: Managing Risks in the Use of Radioactive Sources and Detection Portals

Modern customs and freight-inspection services rely increasingly on technologies involving ionizing radiation. Whether through fixed or mobile X-ray scanners, sealed radioactive sources, neutron-based interrogation systems, or passive detection portals, these tools are essential for identifying threats, contraband, hazardous materials, and security risks. Their use, however, requires a rigorous radiological-protection framework to ensure safety, regulatory compliance, and the protection of both staff and the public.

1. Inspection Technologies Used in Customs and Freight Operations

1.1 Sealed Radioactive Sources

Some legacy or specialized systems employ sealed sources such as:

• Cesium-137 (gamma emitters for density analysis or pipeline inspection),

• Cobalt-60 (high-energy gamma imaging),

• Americium-Beryllium (neutron emission for material interrogation).

These sources present potential external exposure risks if shielding is compromised or if the source integrity is damaged.

1.2 High-Energy X-Ray Scanners

Used for container, truck, and pallet inspection:

• Linear accelerators (1–9 MeV) for cargo imaging,

• Low-energy systems for baggage or parcel scanning.

Key risks include scattered radiation, beam misalignment, shielding degradation, or interlock failure.

1.3 Passive Detection Portals

Installed at borders, airports, ports, and freight hubs:

• Gamma portals,

• Neutron portals,

• Combined radiation-detection gantries.

They do not emit radiation, but their presence requires staff to be trained in alarm response, isotopic identification, and incident management.

2. Radiological Risks for Customs and Freight Personnel

2.1 External Exposure

The primary risk stems from:

• Proximity to active X-ray pulses,

• Improper shielding or accidental entry into the scanning area,

• Handling or approaching damaged sealed sources.

Dose rates can vary depending on system energy, collimation, and operational configuration.

2.2 Internal Contamination (Rare but Critical)

Possible in the event of:

• Source container breach,

• Mechanical damage to a sealed source,

• Improper handling of suspicious radioactive materials seized during control operations.

Even though rare, customs officers must understand contamination pathways— inhalation, ingestion, or wound entry.

2.3 Misinterpretation or Poor Alarm Management

Incorrect response to portal alarms may lead to:

• Failure to identify illicit radioactive materials,

• Exposure due to mishandling of genuine radioactive items,

• Delayed or unsafe cargo immobilization procedures.

3. Essential Radiological-Protection Measures for Customs Services

3.1 Engineering Controls

• Physical barriers and shielding around X-ray systems.

• Verified interlock and emergency-stop systems.

• Monitoring devices (gamma, neutron, and area-dosimetry systems).

• Dose-rate mapping and periodic verification of beam geometry.

3.2 Operational Measures

• Strict access-control zoning during scans.

• Lockout procedures ensuring no personnel remain in scanning areas.

• Real-time radiological monitoring during high-energy operations.

• Defined safety distances for mobile inspection systems.

3.3 Personal Protective Measures

Although PPE is less relevant for external irradiation risks, customs personnel must be equipped with:

• Personal dosimeters (active or passive),

• Alarm dosimeters for high-energy scanning zones,

• Training in contamination-control measures for handling seized radioactive items.

3.4 Training and Competency Requirements

A robust radiological-protection program includes mandatory training in:

• Fundamentals of ionizing radiation,

• Equipment-specific risks and emergency stop protocols,

• Alarm management for detection portals,

• Procedures for identifying, isolating, and securing radioactive goods,

• Regulatory compliance, transport rules, and reporting duties.

4. Incident Prevention and Emergency Preparedness

Service units must maintain:

• Emergency procedures for source loss, damage, or suspected contamination,

• Protocols for sealed-source security breaches,

• Clear communication pathways with national radiation-safety authorities,

• Arrangements with specialized radiological-intervention teams,

• Annual drills simulating realistic scenarios (lost source, abnormal portal alarm, malfunctioning accelerator).

5. Conclusion

Radiological-protection management in customs and freight operations is not an accessory measure—it is a critical operational requirement. The use of radioactive sources, high-energy X-ray systems, and detection portals enables high-precision, high-throughput security screening. Yet these technologies demand rigorous engineering controls, operational discipline, continuous training, and a structured safety culture.

By integrating radiological risk assessment into everyday practice, customs services strengthen not only the protection of personnel but also the national capacity to intercept hazardous materials, prevent illicit trafficking, and secure international trade systems.