One of the world's largest nuclear reactors will start commercial operation in Finland in April. This will be the first time in about 15 years that a new nuclear reactor will operate in Europe.

The plant's operator showed media the No. 3 reactor at the Olkiluoto nuclear power plant in southwestern Finland on Tuesday.

The reactor is a new type called a European pressurized reactor, which is manufactured by French and other companies. It generates a maximum power output of 1,600 megawatts, one of the world's largest, enough to meet 14 percent of the country's electricity needs.

Officials say they have introduced the latest safety measures, including installing four independent emergency cooling devices and a core catcher, a device to cool the molten nuclear fuel in the event of an accident.

Construction began in 2005, but a spate of problems occurred, such as trouble with key components. This has caused the start of operation to be delayed for more than 10 years. The initial target year for operation start had been set for 2009.

Local media say its construction cost more than 11 billion euros, or about 11.6 billion dollars. The amount was more than triple the initial estimate.

In Europe, France plans to construct six nuclear reactors, and Britain and Poland also plan to build multiple reactors. The move is part of their efforts to respond to the situation in Ukraine and other factors, by making active use of nuclear power.

But challenges remain such as prolonged construction periods and bloating costs, in addition to ensuring safety.