Money-oriented thinking is a road to economic misunderstanding. The economy is about stuff. In practice one often measures all the stuff using money, yes, because what else would one use? but as a proxy measure for its value; it's never actually about the money itself.
(stuff = "final goods and services" to be technical)
Energy witch can be food, oil, gas, the energy transformator is a human (or his brain) a maschine or a animal, and the exchange between energie to the endresult is often money. So money/exchangemedium has just the worth both partys agreed on.
Now you are measuring electricity instead of the light you read by, and fuel instead of the vacation trip you take with it. You have worsened the problem I refer to.
Yes. The demand for low background steel and lead is in the few dozen tons per year max, not millions of tons per year. Salvaging it is probably at least an order of magnitude cheaper than making new low background steel once you realize the amount of hassle involved. Furthermore, it's fairly easily recycled if you're not launching it into space (which is a common use case for the stuff, since building space probes to study the cosmic background is all the rage these days).