A new method could greatly reduce the time and expense needed for certain important safety checks in nuclear power reactors. The approach could save money and increase total power output in the short run, and it might increase plants’ safe operating lifetimes in the long run. One of the most effective ways to control greenhouse gas emissions, many analysts argue, is to prolong the lifetimes of existing nuclear power plants. But extending these plants beyond their originally permitted operating lifetimes requires monitoring the condition of many of their critical components…