CO2 is not the only thing that counts. One of those "clean" nuclear plants blows up and we can essentially close our countries or all die of cancer.
In terms of existential threats to human life as we know it, it is.
The choices aren't "renewables and nuclear" or "renewables and ponies and magical unicorns." The choice is what proportion of energy do we want from nuclear vs renewables vs fossil fuels.
The best option is reducing energy requirements. After that, though, a large proportion of every unit of nuclear energy you ban goes straight to fossil fuels. Which is death.
And a nuclear accident would not involve closing the whole country, it would involve an exclusion zone of 10-20 km (Fukushima exclusion zone is 20km, but it include zones where the residue radioactivity is <50 mSievert, way less than some natural radioactive places), a whole lot of economic damage (but negligible compared to climate change), and between 0 and (at worst) a few thousand deaths.
German plants are old. There's issues with a few of them. Decommissioning them seems inevitable. The question is whether building new nuclear plants, at probably about 15+ years for the first plant to start operations, is really a better option than investing in renewables?
I am not saying that Germany should invest in nuclear instead of renewable, but in nuclear along with renewable. And yes 15 years is a long time, but still a lot less long than 30 years (and Germany lost 10 years by being stubborn about nuclear).
And other countries that want to do a energy transition should not make the same mistakes as Germany. And political parties in France that want to close nuclear plants are environmentally severely misguided.
Fission is a pointless, dirty, expensive technology when it comes to power generation on Earth. It is also not that friendly to the environment once you consider the huge infrastructure you have to operate. But the worst thing is that it is not scalable. Think about exchanging all coal and gas power plants with nuclear reactors, consider the safety and proliferation issues and then tell me that PV with chemical storage is not much simpler solution.
Until we've gotten rid of coal shutting down nuclear and delaying decommissioning of coal to take up the slack involves causing mass death.
Coal is only 'acceptable' because the consequences are not as immediately visible.
PV might well be a better option once we've shut down all fossil fuel plants but in the meantime shutting down nuclear is irresponsible and immoral if it delays decommissioning of other types of plants.
Chernobyl's unit 4 was destroyed by an explosion.
Fukushima had multiple explosions that destroyed the upper levels of reactor buildings, and ruptured the containment of unit 2.
During the three mile island accident there were several days where engineers were sweating bullets because there was a hydrogen gas bubble at the top of the pressure vessel, and they were afraid it would explode. It was only after about a week of effort that they were able to eliminate the H2 bubble.
Every nuclear reactor has the possibility of immense damage due to explosion - steam explosions, explosive gas, and secondary systems such as diesel and electrical system. It is one of the primary hazards that control systems and emergency cooling and venting are there to deal with. Lying to everyone that it's not possible isn't helpful to the nuclear community.
I do not know how to respond politely to such a ridiculous statement.
To clarify: “great” is no absolute, an NPP that generates electricity is obviously better than one that explodes. It also depends on the size of the explosion. A Hiroshima-class explosion would be acceptable, the one of a tsar bomb might not be. Also an NPP that fails like that would still kill its operators and perhaps some unlucky farmers. But compared to the actual worst case, that's negligible.