It's not really needed. Waste is a boogeyman, but not really a problem. It takes an incredibly small volume to store the waste, and it can be reduced with reprocessing to run in the exact same reactors.
At some point in the future when there actually is a huge amount of waste causing issues, then it might make sense to build a reactor to use it.
Have a look at the size of the Finnish waste repository.
"They'll hold a total of 5,500 tonnes of waste," says Joutsen. "So Onkalo will take all the high-level nuclear waste produced by Finland's five nuclear power plants in their entire life cycles."
I don't think even one of those fast fission reactors is still in operation. Wonder why that is.
It's not really needed. Waste is a boogeyman, but not really a problem. It takes an incredibly small volume to store the waste, and it can be reduced with reprocessing to run in the exact same reactors.
At some point in the future when there actually is a huge amount of waste causing issues, then it might make sense to build a reactor to use it.
Have a look at the size of the Finnish waste repository.
https://www.bbc.com/future/article/20230613-onkalo-has-finland-found-the-answer-to-spent-nuclear-fuel-waste-by-burying-it
The Finnish repository is designed with a life of 100,000 years. Homo sapiens (i.e us) have existed for about 300,000 years.
Article about the problems warnings that will comprehensible in 10,000 years https://www.bbc.com/future/article/20200731-how-to-build-a-nuclear-warning-for-10000-years-time