It's clean in the sense that it isn't generating CO2. But it is a finite resource. Also, the environmental impact of a nuclear power plant is non-negligible.
Everything is finite. Solar and other "renewables" aren't clean or renewable because the components don't live forever and their manufacturing requires rare earths which are a finite and very unclean to mine. AFAIK rare earths are not being recycled so we are just sweeping the dirty under the carpet and not really greenifying the energy. But for countries that currently burn coal anything would be an improvement.
Nuclear is finite but so is coal and oil and we are nowhere close of running out of it. New reserves will be discovered once there's demand. And used fuel can be recycled in breeder reactors.
I'll take your word for it as there's dozens of ways to build a panel and some do contain rare earth elements but I don't know how widespread they are because they are probably expensive. But the point still apply because even if they don't contain REE they contain other elements that are also finite. Also consider batteries which will be required for load balancing, lithium is very far from abundant and it's extraction is very far from green.
