Safety

Effective Safety Features

The safety features of OL3 are designed with the focus on safety systems, protection against abnormal events and minimizing the damage such abnormal events might cause.

The main safety systems of the OL3 are effective. They are compised of quadruple identical and redundant subsystems; for added safety and to avoid simultaneous failure, each of the four systems is physically separated from the others into different facilities and buildings. In an abnormal operating condition, each one of the sub-systems is capable of performing its safety functions independently.

The reactor building is a double-shelled reinforced concrete structure with a pressure-resistant and gas-tight inner shell. The inner shell is designed to retain its integrity even in the case of a very severe accident. The outer shell is a physical protection against external hazards and is strong enough to sustain even a direct crash by a large aircraft.

The management of extremely unlikely reactor events such as those leading to meltdown has been incorporated already in the basic design of OL3.



In the extremely unlikely case of a reactor core meltdown, the core melt flowing from the reactor pressure vessel is conveyed to the core catcher at the base of the reactor building, where cooling is provided until the core melt solidifies

Strict safety requirements

The design requirements specified for OL3 represent the very latest knowledge in the field of reactor safety. The plant unit fulfils Finnish and European nuclear power plant safety requirements, and in many aspects the requirement level exceeds the international level.

In Finland, the general principles of nuclear safety are decided by the government. Detailed instructions are prepared by the Finnish Radiation and Nuclear Safety Authority (STUK), which also controls compliance with them.

The most important and latest international safety recommendations and requirements have also been taken into account in designing the new power plant unit, e.g. the Europen utility reguirements (EUR) defined by European power companies and the safety and quality recommendations of the International Atomic Energy Agency ( IAEA).