Safer nuclear power
The worst nuclear accident in U.S. history took place in 1979 at the Three Mile Island (TMI) nuclear generating station in Pennsylvania. Radioactive gases were released, but the quantities were low enough that, evidently, no one was hurt.
The more recent Fukushima disaster was similar to the TMI event, in that each was a loss-of-coolant accident (LOCA), which is essentially a plumbing problem: plant operators are unable to pump cool water through the reactor core, causing the core to get hotter and hotter.
Even though any normal failure incident (faulty pump, earthquake, etc.) that could lead to a loss of coolant triggers a scram, in which control rods are inserted to halt the nuclear fission reactions, radioactive elements continue to generate heat inside the reactor as they decay.
That by itself wouldn’t be so bad—plant operators could just wait out the radioactive decay, after which the temperature would start to drop—if there weren’t a second heat source inside the reactor. As the core temperature rises above a particular threshold, the thin tubes that encase each of the reactor’s tens of thousands of fuel rods begin to oxidize, generating additional heat.
Without cooling water, that additional heat continues to escalate temperatures, melting core components and eventually leading to containment failure and serious public health risk. Now, Los Alamos scientists, in collaboration with scientists from the Idaho and Oak Ridge national laboratories, are investigating a way to prevent that second heat source from kicking in.