Why did he do that?
Aluminum is cheaper.
That, and he is a total Luddite.
It's no accident that ever since the presidency of former Nuclear Navy Carter, there hasn't been a single nuclear power plant built in the US (although scores have been built world wide) forcing our very high dependence on 'turm'oil from the middle east.
Jimmah also forbid fuel rod recycling, forcing the industry into storing a goodly percentage of their reusable raw materials.
Other countries recycle, we have the extremely popular Yucca Mountain storage facility.
He loves the third world, and wants us to be just like them...