Every nuclear plant operator pays a portion of their receipts into a
decommissioning fund. The fund is enough that although
San Onofre Nuclear Generating Station was closed early (28 years instead of the expected 50), its decommissioning fund ($4.1 billion) is sufficient to handle the estimated decommissioning costs ($4.4 billion). (The fund amount is a current snapshot, while the decommissioning costs are spread over decades. So the current fund will accumulate interest over the decades, and will be more than sufficient to pay for costs).
If you add up the highest estimates I could find for the costs of the Fukushima and Chernobyl cleanups (
$660 billion and
$700 billion respectively), and divide it by the
total sum of nuclear power generated (about 2300 TWh * 30 years + 2300 TWh/2 * 20 years), their cleanup only end up costing $1.46 trillion / 92000 TWh = about 1.5 cents per kWh. If you use average cleanup cost estimates, it's closer to 0.5 cents per kWh. If you ask me, I'm more than willing to pay that for nearly unlimited, on-demand, greenhouse gas-free electricity. Since the average U.S. household uses 10700 kWh/yr, it amounts to just $160 per household per year worst-case ($53.5 if you go with the average). By contrast, the $25 billion in forgiven student loan debt thus far has cost us ($25 billion / 144 million taxpayers) = $174 per taxpayer. The numbers are even more favorable for nuclear in other countries, where household electricity use is lower, and price is higher.
The only problem nuclear power has is that it's an incredible concentrated power source, so you don't need a lot of nuclear plants to supply a lot of power. This means when there's a single accident or disaster, its scope is correspondingly much bigger. But to properly assess the drawbacks, you need to compare the costs against the amount of power generated. Otherwise you get into the same situation as with car and plane crashes. Because the fatality figures are much higher when a plane crashes, people who don't think twice about getting into a car have an irrational fear of flying. Even though planes are much safer than cars.
This also affects the viability of insuring nuclear plants. Insurance requires large numbers to average out probabilities - as you increase the size of the insured population,
the width of the bell curve shrinks. Insuring 3000+ gas and coal plants is easy - because there are so many of them their premium ends up close to the average cost of an accident. By contrast, insuring 55 nuclear plants is a lot harder, and their premium ends up being closer to the worst-case cost of an accident rather than the average cost. Normally in situations like this the government steps in an act as insurer, because it's for the long-term greater good. But unfortunately our policies regarding this are largely driven by people who evaluate it emotionally, rather than rationally and mathematically. This is largely what's driving the push to small modular reactors: not waste reduction, but as a workaround for the math which makes it more expensive to insure a few really large plants, compared to breaking up those plants into lots of smaller ones with the exact same risk.