Technologists from Cuba's Centre for Radiation Protection and Hygiene (CPHR) successfully removed 52 disused sealed radioactive sources from the country's only food irradiation plant on 11 and 12 January, transferring them to the waste management facility for safe and secure storage. Organized for the first time under the supervision of Cuba's nuclear regulatory authority, this operation demonstrated the experience and skills acquired by CPHR staff following IAEA capacity building support in this area over many years.
"This achievement represents the latest milestone in the country's efforts to re-establish its discontinued food irradiation services," said Raquel Scamilla Andreo Aledo, IAEA Programme Management Officer for Cuba. "These efforts further demonstrate Cuban efforts to promote the safe and secure implementation of radiation applications for the benefit of the economy."
Regaining capacities, resuming operations
In 1987, with IAEA support, Cuba's Food Irradiation Plant (PIA), the first and only facility of its kind in the country, was put into operation at the Food Industry Research Institute (IIIA) in Havana with the aim of improving food quality, reducing spoilage and destroying bacteria through food irradiation.
A decade later, however, the PIA discontinued its irradiation services due in part to the decreasing radioactivity of their sealed sources and the need for technological improvements at the facility. In 2005, Cuba's Nuclear Energy and Advanced Technologies Agency (AENTA) developed a strategy to re-develop the country's irradiation capacities. The strategy was supported by an IAEA technical cooperation (TC) project[1] designed to promote and encourage radiation services in important sectors of the country's economy.
Following expert missions, training courses and the provision of equipment through the TC programme, in February 2019 IAEA experts and Cuban specialists installed new cobalt-60 radioactive sources at PIA, enabling the facility to reopen its doors and make its services available after a near 25-year hiatus.
To finalize the installation of the new sources, their low-activity predecessors had to be removed. However, without a suitable container available for the safe and secure transport and storage of the disused radioactive sources, they could not be transferred to Cuba's radioactive waste storage facility and consequently were deposited into a reserve pit, located in the same facility of the irradiator. These activities were carried out with the assistance of IAEA experts.
In the facility's reserve pit, pictured here, there are 20 holes into which the sealed disused sources were temporarily deposited, before their safe extraction was organized. (Photo: J.C. Benitez Navarro/IAEA)
"The reserve pit has the same design as the main irradiator pit," explained IAEA Nuclear Engineer Juan Carlos Benitez Navarro. "Its function is to temporarily store sealed radioactive sources in special circumstances, for example for resourcing, maintenance, or repair works in the irradiator."
In mid-2021, the transport and storage container was procured through a regional TC project[2]. The container provided adequate shielding for the 52 disused radioactive sources. Subsequently, in early 2022, operations to extract the sources from the reserve pit began.
Organizing a safe source removal operation
Before launching the sealed radioactive source removal operation, CPHR experts received guidance and training in the handling of the container, its auxiliary components and their corresponding tools. Special devices had to be designed and manufactured to facilitate the alignment of the container with the channels of the reserve pit.
A comprehensive safety assessment was also conducted, based on the IAEA Safety Standards, identifying safety barriers and any potential for accidents and their consequences. Operational doses under normal and accident conditions were estimated and a radiological emergency response plan was prepared to ensure the safety of the experts and the success of the operation.
All related documents were submitted to the Nuclear Safety Directorate (DSN), the national regulatory authority of Cuba in radiological and nuclear safety matters, which carried out its evaluation and approved the CPHR plans.
Finally, tests were carried out at the reserve pit to evaluate and verify the correct operation of the container and the custom source handling tool.
On 12 January, the 52 disused radioactive sources were removed from the reserve pit and loaded to the container as planned and transported to the CPHR's waste management facilities where they are now safely stored.
The IAEA safety standards help to ensure appropriate safety measures are implemented during the management of disused sealed radioactive sources.
[1] CUB1012, "Improvement of Radiation Services in Cuba"
[2] RLA9078, "Enhancing the National Regulatory Framework and Technological Capabilities for Radioactive Waste Management
