UK sealed radiation sources – delivering a new and cost-effective solution
The UK had an urgent requirement to collect a backlog of radiation sealed sources from across the country and transport them for safe disposal.
The sources had accumulated for decades as a by-product of numerous medical, research and industrial processes. A new, more flexible method of managing and transporting the sources was needed to address the backlog. The NDA turned to NTS to find a new and cost-effective solution.
The sources were wide ranging in terms of radionuclides and source strengths – including (but not limited to) sources used in lightning conductors, test sources for radiological instruments and smoke detectors. This challenged the shielding assessment in two ways:
- How to define a source acceptance condition for transporting such wide-ranging source types.
- How to demonstrate that the IAEA transport regulations for Normal Conditions of Transport (NCT) could be met.
The transport solution was to take an existing package, modify and refurbish it to create a flexible package that would be suitable for use by the source collection agencies. We based our shielding assessments on all radionuclides included within table 2 of the IAEA transport regulations. This was the ideal packaging solution for our customer, the NDA.
We also had to devise a novel approach to demonstrate safety during NCT. It wasn’t possible to design bespoke package internals because of the unique nature of many of the sources. We adopted a two-pronged approach.
- Firstly, we were able to demonstrate that no matter how much movement of sources occurred, the Routine Conditions of Transport (RCT) dose rate limit would not be exceeded due to the shielding assessments we had conducted.
- Secondly, that the risk from NCT dose rate increases was ALARP (As Low As Reasonably Practicable).
The re-purposing of an existing package (1648C) was a safe and cost-efficient way of supporting UK source collection agencies. This multi-modal transport of sealed sources has ensured that these sources are properly managed and disposed of.
The approach gave them flexibility to transport a wide range of sources and was achieved by a combination of technical expertise and close collaboration with the regulator to deliver a solution that was fit-for-purpose.