this post was submitted on 04 Apr 2025
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Summary

A new Innofact poll shows 55% of Germans support returning to nuclear power, a divisive issue influencing coalition talks between the CDU/CSU and SPD.

While 36% oppose the shift, support is strongest among men and in southern and eastern Germany.

About 22% favor restarting recently closed reactors; 32% support building new ones.

Despite nuclear support, 57% still back investment in renewables. The CDU/CSU is exploring feasibility, but the SPD and Greens remain firmly against reversing the nuclear phase-out, citing stability and past policy shifts.

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[–] peregrin5@lemm.ee 1 points 3 days ago (6 children)

Nuclear power is great. But I do wonder if they might be targets in a war with Russia or something. Can they be prevented from meltdown in the case of a missile strike?

[–] TheTechnician27@lemmy.world 7 points 3 days ago* (last edited 3 days ago) (1 children)

Huh? Modern nuclear power plants automatically stop the reaction. In addition to other safety features monitoring things like temperature, radiation, etc. for automatic shutoff, the rods are held in place via electromagnetism. In the event of a power loss, the reaction will stop because the rods fall out of place. (This may just be one type; other modern reactors have ways of automatically stopping the reaction in the event of a power loss.)

[–] ClassyHatter@sopuli.xyz 10 points 3 days ago (1 children)

The main reaction can be stopped within seconds, but the secondary reaction cannot. If the reactor isn’t sufficiently cooled by running water through it, it will meltdown due to the secondary reactions.

[–] InvertedParallax@lemm.ee 2 points 2 days ago (1 children)

Those are old designs, new ones basically stop once the water is removed.

Hence the 'negative void coefficient', modern designs lose reactivity as the water is removed.

Look at pebble bed and other designs.

[–] ClassyHatter@sopuli.xyz 1 points 2 days ago (1 children)

As far as I know (I'm not an expert), negative void coefficient only affects the fission reaction, i.e. the controlled splitting of uranium atoms. The uranium atoms split into smaller unstable atoms, which decays over time causing heat. If the decay heat isn't removed, the core will melt.

Pebble Bed Reactors seem to be generation IV reactors, and I don't think there are any generation IV reactors in commercial use as of today. Again, my knowledge is limited, but I believe most reactors in commercial use are some kind of water cooled, water moderated reactors. For example, European Pressurised Reactor (EPR) is one of the latest designs commissioned in commercial use, and that design includes 4 emergency coolant systems.

[–] InvertedParallax@lemm.ee 2 points 2 days ago

https://en.wikipedia.org/wiki/HTR-PM

China has the pbr in production as modular reactors.

When the reactor temperature rises, the atoms in the fuel move rapidly, causing Doppler broadening. The fuel then experiences a wider range of neutron speeds. Uranium-238, which forms the bulk of the uranium, is much more likely to absorb fast or epithermal neutrons at higher temperatures. This reduces the number of neutrons available to cause fission, and reduces power. Doppler broadening therefore creates a negative feedback: as fuel temperature increases, reactor power decreases. All reactors have reactivity feedback mechanisms. The pebble-bed reactor is designed so that this effect is relatively strong, inherent to the design, and does not depend on moving parts. This negative feedback creates passive control of the reaction process.

Thus PBRs passively reduce to a safe power-level in an accident scenario. This is the design's main passive safety feature

The west is irrationally afraid, but China understands nuclear is inherently safer than fossil fuels after having lost thousands to pollution.

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