Speakers
Description
In accordance with SSR-6, paragraph 308, competent authorities are required to periodically assess radiation doses to individuals resulting from the transport of radioactive material, ensuring compliance with the system of protection and safety outlined in GSR Part 3. This synopsis will present the main findings from a recent Norwegian study conducted to meet this requirement.
Phase 1: Transport Characteristics
The study was implemented in two phases. The first phase, carried out in 2024, focused on mapping the characteristics of packages and consignments transported in Norway during 2023. A mandatory questionnaire was distributed to more than 370 companies, nearly reaching an 80% response rate. The results showed that approximately 25,000 packages were consigned by Norwegian companies in 2023, of which near 13,500 were exported. Additionally, around 5,500 packages containing radiopharmaceuticals were imported. Nearly 96% of all packages were transported by road at some point in the transport chain. Type A packages were the most common, accounting for 87% of all packages, followed by excepted packages (7%), industrial packages (5%), and Type B packages (2%). Most packages had low Transport Index (TI) values, with only 0.3% exceeding TI 5. It is estimated that between 1% and 4% of consignments had a TI above 5.
The analysis also revealed that four industry sectors accounted for 96% of all consignments: the medical sector dominated with 78% of packages, followed by oil and gas (9%), nuclear density gauges (6%), and industrial radiography (2%). The medical sector alone contributed approximately 60% of the overall TI of all consignments. These data will support the Norwegian regulator’s risk-based compliance assurance program.
Phase 2: Dose Assessment Related to the Transport of Radiopharmaceuticals
The second phase of the study, conducted in 2025, assessed doses to workers and the public from the transport of radiopharmaceuticals, which pose the highest exposure risk, as identified in Phase 1 of the study. The Norwegian Radiation and Nuclear Safety Authority (DSA) performed direct dose measurements during three road transport operations and one handling operation at an airport terminal. Public dose estimates were also made. In addition, two drivers were equipped with electronic personal dosimeters (EPDs) worn on the chest for two weeks, and doses were recorded for each transport operation.
Measured doses were compared with theoretical estimates based on TI and the duration of activities, and linear models were developed to describe the relationship between measured and calculated doses for both handling and driving. The models showed a strong linear correlation.
Further analysis revealed that asymmetric exposure during handling and driving significantly affected dose assessment. When EPDs were worn only on the chest, the actual dose was underestimated by 13–39%, particularly when no shielding was present between the cab and cargo or during long-distance driving. The estimated maximum dose to the public was 0.1 mSv. At the airport terminal, workers were monitored with passive dosimeters and finger dosimeters for two months, with no doses registered. Following a visit to the terminal, and based on EPD measurements, a cargo handler at the terminal could receive an annual dose of approximately 0.5 mSv.
This study provides the first comprehensive national assessment of radiation doses from the transport of radioactive material in Norway. The findings confirm that doses to workers and the public remain low, while highlighting factors such as asymmetric exposure that warrant attention in regulatory oversight and operational practices.
