You can build systems to fail safe, so that lack of proper maintenance leads to the plant becoming safely inoperable, and only grossly-improper maintenance would cause a fallout incident.
Is this guaranteed to work? The Chernobyl disaster was caused by grossly-improper maintenance, so… :shrug:. No matter how many physical safety mechanisms you have, a determined mechanic could remove them – but at that point, it becomes deliberate sabotage, which is rare, detectable, and not unique to nuclear power plants. (You could probably kill more people by destroying the right dam in the middle of the night.)
... and with every other energy source. The only difference is that some spread the damage out enough to the point where people stop caring vs. (somewhat) larger but incredibly rare incidents that make headlines.
And that's before you take into account second order risks like people dying because they can't afford to heat properly during winter.
The damage from Fukushima has been so small that it wouldn't make it past regional headlines if it didn't involve the scary word "nuclear".
Solar panels fail pretty safe. I guess there's fire risk? Wind turbines are generally located in areas where rapid unscheduled disassembly would be harmless.
Nuclear power plants don't need to be built at scale. I reckon we could get away with a few thousand in the entire world. And by "grossly improper", I mean things that are more expensive than correct maintenance, and make the power plant work less well: I can't rule out that anyone would want to do that, but you'd need a bona fide conspiracy (or some kind of purge of all available experts) to even attempt it.
Is this guaranteed to work? The Chernobyl disaster was caused by grossly-improper maintenance, so… :shrug:. No matter how many physical safety mechanisms you have, a determined mechanic could remove them – but at that point, it becomes deliberate sabotage, which is rare, detectable, and not unique to nuclear power plants. (You could probably kill more people by destroying the right dam in the middle of the night.)