Design of spent fuel interim storage of Hanhikivi-1 newbuild NPP

Decision in Principle was applied for both NPP and spent fuel storage at the same time and the facilities share some of the auxiliary systems. In addition, STUK needed to have a holistic view on nuclear safety in Hanhikivi, so it was necessary to design the spent fuel storage in parallel with the power plant itself. The construction permit material, including PSAR of spent fuel storage, was submitted to Radiation and Nuclear Safety Authority (STUK, Säteilyturvakeskus) for review.

After STUK’s first comments were received, the PSAR was updated. Safety regulations (YVL guides) were also renewed during the process, and these changes were taken into account systematically. Also Human Factors Engineering (HFE) program was added to design process and Operational Experience Review was performed in spent fuel storages of Loviisa and Olkiluoto.

The final updated construction permit material was sent to STUK in autumn 2021.

While spent fuel storage designing is compulsory for all nuclear power plants in Finland, the project as a whole was unique and had some unforeseen challenges. Requirement management played a major role, as the safety requirements (YVL guides) were updated by STUK in the middle of the project. Despite the hurdles, the requirements management succeeded, Fortum experts could adapt to changing requirements quickly and the project was finished on time and within planned budget.

The intergenerational learning process was emphasised during the project. At the beginning of the project, there were still retiring senior experts available, whose learnings and responsibilities were successfully transferred to other experts. It was also significant achievement to systematically collect practical user experiences from fuel storage facilities in Loviisa and Olkiluoto, and use these experiences as valuable design input. Also methods to implement Human Factors Engineering (HFE) aspects to the design were systematically developed.

The project was large in scope, and during the project we enhanced our competence by multi-disciplinary transfer of knowledge between generations of Fortum´s engineers, according to project manager Jukka Hautojärvi.

As a trustworthy, experienced, and large organization, Fortum could support Fennovoima in many different phases of initial planning of a newbuild nuclear power plant. Prior knowledge of Finnish official requirements proved essential since the regulations are strict and can prove difficult to fulfill. As the owner of Loviisa Nuclear power plant, Fortum has prior experience of dealing with nuclear waste and preparing interim storage planning and implementation. Being a large company with extensive knowledge on nuclear projects, Fortum could quickly form an efficient team of professionals to support Fennovoima with spent fuel storage design alongside many other projects.

The project was Fortum’s first in which Human Factors Engineering (HFE) project philosophy was utilized. In practice, HFE accounts for wider range of risks than conventional project planning by considering human errors as expected and natural occurrences which can be mitigated similarly to any other sources of risks. HFE was used in all of the phases of planning with excellent results which further increased the reliability of the results.