How Old Is Too Old for a Nuclear Reactor?

The nuclear industry’s efforts to keep aging plants operating highlight questions about nuclear power’s future in the U.S.
As the ongoing climate summit in Paris has moved from rosy exhortations by world leaders to the gritty, behind-closed-doors business of crafting an international agreement on limiting emissions of greenhouse gases, one theme has emerged: it is now broadly acknowledged that any path forward must include nuclear power.