FiR1 decommissioning

VTT’s FiR 1 TRIGA Mark II reactor had been operated from 1962-2015 initially for neutron and reactor physics research and later for medical treatment. During its lifecycle the reactor output had been upgraded from 100 kW to 250 kW. At the end of its lifecycle, decommissioning license was granted to VTT in June 2021 by the Government of Finland. The contract on decommissioning services, signed in March 2020 between VTT and Fortum, covered the dismantling of FiR1 and all necessary nuclear waste management services, including final disposal.

The decommissioning project had two distinctly separate phases:
1.    Decommission planning and support
2.    Site preparation, dismantling, and waste management

The planning and support phase consisted of decommissioning site design, developing radioactive waste management process, and planning of dismantling and radiation protection. In addition, Fortum created relevant documents for operational radiation safety and work instructions for dismantling and disposing of the reactor. Moreover, specific waste containers and radiation shields were also developed and manufactured for the most activated waste. Fortum also supported licensing and spent fuel management. The planning and support phase was completed in December 2022.

Site preparation and dismantling started in the beginning of 2023. The site was special in nature since it was situated at an active university campus, which was something that had to be taken into consideration, especially from a radiation safety aspect. Fortum’s responsibilities included site preparation for dismantling, implementation of radiation protection and waste management arrangements as well as all demolition work. When the dismantle was finished, the site was handed over to VTT in May of 2024.

The waste management, which was carried out alongside dismantling, consisted of sorting, packing, transportation, final storage and disposal at Loviisa NPP LILW repository. Characterization of waste was also a vital step in the process of waste management, and in this project it was a shared responsibility between both Fortum and VTT. While the reactor dismantling was the first of its kind in Finland, it was also the first time external nuclear waste has been permitted to be disposed of at the Loviisa repository.

All reactor components had predetermined waste handling procedures. Depending on activity, nuclide vector and material, waste components were sorted into three different final disposal package types. Following the packing, waste was characterized and transported to the temporary storage area. When there was enough waste in storage for one transport, the waste containers were packed inside of an official public road transport container. After fulfilling related waste acceptance criteria the waste was transported to the Loviisa final disposal facility and ownership of the waste was transferred from VTT to Fortum.
 

A safe working environment was our number one priority throughout the project, both from a radiation safety and occupational safety perspective. 

Regarding radiation safety it is noteworthy that no dose limits were exceeded nor did any personal contamination take place during the entire work process. Furthermore, given that the site was situated at a busy university campus, extra attention was given to radiation safety related to civilian bystanders and passing traffic. In fact, it was a key focus point that no members of the public received an exposure higher than 4 µSv. Compared to the dose that an average Finn receives annually, about 5mSv (STUK, Radiation and Nuclear Safety Authority), this is quite unnoteworthy.

General safety measures were taken to ensure a harmless working environment. These measures were for instance constant monitoring of the work place, identifying near hazards and potential risks, and taking proactive action to avoid any hazards that could result from said risks. As a result of this proactive safety culture, no personnel absence due to accidents occurred. 

The project was executed in close cooperation with VTT and Finland’s government officials. Since such a project had not been done in Finland before, the planning and documentation was created with utmost thoroughness to ensure that all stakeholders were satisfied with the progression. Fortum’s internal collaboration likewise increased as experts from Fortum Loviisa NPP, Nuclear Services, and Radiation Safety -teams all had essential roles in the project.

Fortum utilized several modern tools for planning the decommissioning. A virtual model (eSiteview) of the site was created to support remote planning. Radiation modelling (MCNP and HVRC VRdose®) was used to optimize the work process and calculate as well as visualize radiation doses in different work phases. All reactor internals dismantling phases were modelled with 3D software (Solid Works, Micro Station etc.) to ensure smooth execution and to streamline work plans.

Fortum’s vast nuclear and radiation expertise as well as experience with conventional dismantling projects assured reliable operation with both desired schedule as well as cost-effective solutions. Fortum has a unique set of skills in the Finnish nuclear field. The project could be carried through, from initial project planning all the way to final waste disposal, by a single company with wide array of services that could be utilized at different points of the project.

Alongside general decommission experience gained in the project, Fortum got a concrete improvement in the services provided – from now on Loviisa LILW final disposal site can support Finnish industrial sector with final disposal of radioactive waste.

For the planning and support phase, 25 documents were prepared for licensing and later execution of the project. With planning and preparation finished, the project continued with on-site dismantling in June 2023. By, the second of May 2024, the reactor had been completely dismantled. Waste transportations to the final disposal facility are still ongoing and will be finalized by the end of 2024.

"The FiR1 decommissioning project is the first of its kind in Finland. During the project, the authority has not had existing procedures for such projects, and planning documentation has never been taken this far before. Flexibility was also learned during the project, as support was needed from other organizations, and help has been available in both directions", says Fortum's leading decommissioning specialist Matti Kaisanlahti.

"Overall, the project is unique and new, and a lot of new things were learned during the project. Despite the large workload of the project, the overall schedule has been kept, since the goal of the project has been clear and visible from the beginning. And what's the most important, the customer has been satisfied with the operation of the project and the produced material.", Matti continues.

“The dismantling phase was very swift, thanks to thorough planning and preparatory work. Additionally, it was crucial that we could leverage the strong nuclear safety culture and expertise from Fortum's Loviisa nuclear power plant. Fortum handled everything safely, efficiently, and on schedule without significant delays.”, says Markus Airila, Customer-side Project Manager, VTT