Actually, it is, because there is so little of it.
However, in the Nuclear Waste Policy Act of 1982, the US government declared that only the US government can handle nuclear waster, and nuclear power plant operators have to pay into a fund so that the waste handling will be funded. It then spent the following 38 years doing a grand total of exactly nothing, forcing the power plant operators to store the waste. And not for lack of funds, because the Nuclear Waste Fund sits an an unspent $45 billion.
Please stop pretending nuclear waste was either a financial or a technical problem. It's purely a political problem.
> a law that puts upper cap to damages
Which US law places a cap on damages caused by nuclear power plants?