Commercial nuclear power plant fuel is amazing stuff. Light water reactor fuel assemblies operate in an unforgiving environment—high pressure, high temperature, high neutron flux, steep temperature gradients, challenging chemistry, and hydraulic loads and flow anomalies, among other things. They do it for 18 or 24 months at a time, and by the end of their useful life, most of the original uranium-235 has been used up through violent (on a microscopic scale) fissions, releasing emissions-free energy to power homes, businesses, and factories.
Even after a fuel assembly’s energy production days are over, we expect it to maintain its integrity for decades, or even centuries, during storage, transportation, and, ultimately, disposal. To borrow from the old Timex watch slogan, nuclear fuel takes a licking and keeps on ticking, and that fact makes today’s nuclear power plants feasible.