If only the right-wing parties support nuclear power, does that turn nuclear power into something rightwing?
In Sweden and Norway we have had parties that want to leave EU on both side of the political spectrum.
The EU question has many aspects to it, in particular when it comes to fees, democratic control over laws, and voting rights. You need strong incentives to keep smaller countries that pay way more than they get back and which voting impact is dwarfed by larger countries. An argument I see in both countries is to simply force EU to lower the EU membership fee by putting down an ultimatum.
Norway isn't even in the EU so what gives?
In return they are part of the European Economic Area, which include most aspects of free movement and following of EU regulations.
Some of the information can be gained from wikipedia (including which political parties is in favor or against): https://en.wikipedia.org/wiki/Norway%E2%80%93European_Union_...