I'm mean now

First reason is because we don't use graphite moderated reactors anymore, at least not for power generation. There might be some scientific reactors that still do, but for power generation they're all water moderated. Essentially you have this thing called a neutron moderator that slows neutrons down, which makes collisions with atoms more likely, which increases the rate of fission, which increases the heat production. That's a very surface level explanation, but we really don't need to dig deeper for the purposes of this. Chernobyl used graphite rods as a moderator. If you lose control of those rods, you lose control of the reactor. That's exactly what happened with Chernobyl. Modern reactors use water as a neutron moderator. The same water they're heating up to spin the turbine. If you lose control of the reaction the water boils off. You lose your moderator, and the sustained fission reaction dies out.

The second reason are the control rods. So there's these things called control rods that absorb neutrons, stopping them from causing fission events, reducing heat generation. Chernobyl's control rods took 18-20 seconds to fully drop. In emergencies modern reactors can fully drop their control rods in less than 3 seconds. They also require power to keep /OUT/ of the fuel rods. If you lose power to the rods or the mechanical failsafes/interconnects trigger from it going out of spec the control rods will passively insert themselves, stopping the reaction.

Third is the reactor containment building. If /SOMEHOW/ the two prior failsafes magically don't work the reactor containment building is literally designed to prevent another Chernobyl. Unlike Chernobyl, which was just... out in the open, modern reactors are contained in a reactor containment building, a 1 meter (~3 foot) thick reenforced concrete shell. The safety margins on these structures is insane. You could crash a fully loaded cargo airliner into one, and it wouldn't breach. They're specifically designed for this exact worst case scenario.

Three mile island is the worst commarcial nuclear accident in U.S. history and... It really wasn't spectacular. The cooling system failed, and the emergency shutdown triggered. A coolant valve got stuck open, and a backup system flooded the reactor with coolant. Things worked (almost) perfectly. Reactor design has improved a lot since then, and absurd amounts of redundancy have been implemented. Ironically the worst part of the three mile island incident wasn't related to the the failsafes not working, it was due to a bad compressor. Basically when they were trying to evacuate the reactor vessel AFTER the incident a leaky compressor leaked some radioactive material. HEPA filters stopped any radioactive particles from escaping, but some noble gasses leaked out. There has been no link found between this release and any ill health effects in the surrounding communities.

NB4 "Muh INES" that is a qualitative scale, not a quantitative scale. It literally doesn't account for the scale of the incident.

Also remember that Microsoft is literally restarting the Three Mile Island power plant. There will obviously be a ton of modernizations to comply with the NRC, but yeah. Three Mile Island is coming back online. The US's Nuclear Regulatory Commission is probably the strictest in the world.

As to Fukushima? That killed, MAYBE, one person. I say maybe because they died four years later for lung cancer, and it's basically impossible to draw a causal relationship to that. The earthquake and ensuing tsunami that caused the Fukushima incident? It killed almost 20,000 people, and injured over 6,000 more. Earthquakes and tsunamis happen orders of magnitudes more frequently, and yet people don't generally live in perpetual fear of them.

Per terawatt of energy generation the casualty statistics of various sources look like this:

Coal: ~24.6

Oil: ~18.4

Gas: ~2.8

Hydro: ~1.3

Wind: ~0.04

Nuclear: ~0.03

Solar: ~0.02

So yes, nuclear is objectively safer than wind, and almost as safe as solar. It's also WAY less harmful to the environment than either. Wind requires vast swathes of land sometimes leading to deforestation, disrupts the local weather, and disposal of the blades is a problem as they're not biodegradable, can't be effectively recycled, and can't be sent to normal landfills. We literally have to build specially designed landfills specifically for only windmill blades. There's also the issue of harvesting the rare earth metals used in the rotors, which is a major environmental problem. There's literally a radioactive lake in China as a result of mining rare earth metals. (See Boutou Lake)

Solor has similar issues, as the panels can't be easily recycled, and are generally considered toxic waste as they use leaded solder on the copper ribbons that connect the solar cells.

NB4 "solar panels are made of easily recycled materials", yes they are. That doesn't mean they're easy to recycle, because it turns out those materials are laminated together. You have to separate those materials before you can recycle them, and it turns out that's a bitch and a half to actually do.

Commercial solar installations generally get replaced every 6-10 years. The panels CAN last 20-25 years, but their efficiency drops over time and failure rate increases with age so grid scale solar installations usually replace them well before that. Sometimes those panels get resold for residential installations, but not always. Wind mills last a bit longer at 20-25 years if nothing goes wrong. The NRC license for a reactor is 40 years, and can be extended indefinitely in 20 year increments pending upgrades to meet new regulatory standards.