About the project

We demonstrate the safety of the Hanhikivi 1 nuclear power plant

Fennovoiman ydinturvallisuusjohtaja Juho Helander

The Hanhikivi 1 nuclear power plant’s safety system design's safety has been demonstrated, and there are no significant open safety issues regarding the systems that could require substantial design changes later.

During the past year, we have extensively reviewed the safety solutions of the Hanhikivi 1 nuclear power plant with the plant supplier and STUK. We have also systematically assessed the plant's systems, layout design, preliminary safety analysis report, and safety analyses from the safety perspective.

We are satisfied that we could approve the most important safety systems of the nuclear power plant and submitted the associated documentation to STUK for evaluation. According to our estimate, the safety systems description is sufficient for this stage of the project. In practice, the system design's safety has been demonstrated, and there are no significant open safety issues regarding the systems that could require substantial design changes later. STUK has been reviewing the documentation and issued some requests for clarification concerning, for example, containment isolation, hazard analyses, and safety classification. Many of STUK's requirements resulted from the fact that we have not yet submitted all the licensing documentation, which makes seeing the overall picture still hard at this point. However, requests for clarification, dialog with the authorities, and updating the documentation are a natural part of the licensing process to obtain a construction license for the plant.

At the end of the year, we approved the severe accident management strategy and the related bases. In our view, the design solutions for the containment and the severe accident management strategy guarantee plant safety also during severe accidents. The strategy describes how the leak-tightness and integrity of the containment are ensured in case of a severe accident to prevent any damage to people, the environment, or society from an accident. There are still some open details, but we do not expect them to cause any significant changes to the plant design. The open issues concern, for example, the isolation of smaller penetrations of the containment and missing hazard analyses, particularly regarding fires.

Various safety analyses are required to demonstrate the plant's safety, including thermohydraulic deterministic analyses, probabilistic risk assessments, hazard analyses, and failure tolerance analyses. We have received preliminary analyses from the plant supplier, and there was progress, especially concerning the plant supplier's hazard analyses and failure tolerance analyses in 2020. We use hazard analyses to ensure that the plant will be protected against external and internal threats, such as earthquakes, tornadoes, airplane crashes, and flooding and fires inside the plant. We have reviewed analyses already delivered to us and prepared a large number of our own independent deterministic safety analyses, which we will also use in the license applicant's own safety assessment. In general, our analyses also show that the plant will meet all safety requirements by significant margins.

In 2021, we intend to solve all open issues related to the plant's safety and submit the complete licensing documentation for the construction license application to STUK. We will engage in weekly dialog with STUK regarding the plant's safety and design solutions and update the licensing documentation as needed to fulfill the prerequisites for a positive safety assessment by the authorities and for granting a construction license for the plant.

Juho Helander
Nuclear Safety Director

Juho Helander holds a master's degree in engineering physics and works at Fennovoima as Nuclear Safety Director. Juho has about 14 years of work experience in the field of nuclear safety. He has previously worked at Fennovoima as a reliability manager and Fortum as a risk analysis expert. In his spare time, he enjoys various sports activities such as football and racket games.

Ydinturvallisuusjohtaja Juho Helander

Read more about our work and daily life on the project

Hazard analyses help us tackle safety threats

Internal hazard analyses examin how threat situations occurring inside a nuclear power plant would affect its safety, tells Nuclear Safety Engineer Julia Virtanen.

Julia Virtanen

Radiation is natural

We study the natural baseline level of radiation and radioactive substances in the vicinity of the Hanhikivi 1 -plant site, shares radiochemist Mervi Söderlund.

Mervi Söderlund

Ensuring the nuclear power plant safety

The design and safety assessment of the Hanhikivi 1 plant is progressing with confidence. At the same time, we are preparing for the construction and operation of the plant, says Janne Liuko.

Janne Liuko