The LEGO group has always been protective of their brand and nervous about being associated with potentially violent content, turning down a partnership with the Halo games because of that. For years, they didn't want to make grey bricks because they were afraid kids would use them to build tanks. All this to say, this seems pretty on brand for the LEGO group.
Nuclear powerplants are so safe that they've only had a handful of (admittedly disastrous and high profile) failures, and have killed less people per watt hour generated than even wind and solar power. Nuclear power is the safest, cleanest, most efficient form of green energy we can get right now. Yes, it can be dangerous if not managed properly. But Fukushima, Chernobyl, and Three Mile Island were not freak accidents. Deliberate mistakes were made that were known at the time and should be used as warnings to keep the industry safe, not as sirens that lead is to swear off nuclear energy.