On Friday the Finnish parliament voted for the project with 115 in favour, compared to 74 against. The location for the plant is in Pyhäjoki, just 150 kilometres from Swedish municipalities such as Luleå, Piteå and Skellefteå.
"This is a very sad day as this is one biggest non-nuclear parts in the whole of Europe. Now they want to ruin it by building a nuclear plant," Per Holmqvist of the nuclear free Bothian Bay (Kärnkraftsfritt Bottenviken) activist group told The Local from his home in Piteå.
Reuters reported that the Fennovoima reactor would be supplied and fuelled by Russia's state-owned Rosatom. If the plans pass strict environmental checks then it is expected to go into operation in 2024.
Campaign groups in northern Sweden have been protesting for years about the proposed nuclear plant. A few days before the Finnish parliament gave the green light to the project they presented a petition with 20,000 names opposed to the plan to the government in Helsinki.
"If the project gets off the ground then it will have a massive impact on this part of Sweden. For instance the marine life in our lakes will be affected as the cooling water from the plant will raise the temperature in the sea.
"Of course there are also public health concerns as there will be some radiation emitted from the plant. We also have a lot of tourism up here and no doubt those numbers would drop if there is a nuclear plant being built on our doorstep," said Holmqvist.
At its closest the plant will be 100 kilometres from the Swedish/Finnish coastline and 150 kilometres from several towns in the north of the country.
Finnish energy company Fortum, which has substantial interests in Sweden, recently announced it was buying a minority stake in the Fennovoima nuclear power project.
"We are going to boycott Fortum as a result and not stop campaigning against this. It's just sad that nowadays a government wants to build a nuclear power plant when much of the rest of the world is looking for alternative energy sources.
"We have a responsibility towards our children and that's why we won't give up," added Holmqvist.
Plans for the nuclear plant were first drawn up in 2010 with the whole project estimated to cost in the region of €7 billion. The plant would supply electricity for much of the region if it goes into production.