Final answer:
In a nuclear power plant, the basic reaction is nuclear fission, and if the operation fails to cool the fuel rods adequately, it can lead to a nuclear meltdown.
Step-by-step explanation:
The basic reaction that takes place in a nuclear power plant is nuclear fission. If the fuel rods get too hot, they can cause a nuclear meltdown.
In a nuclear power plant, fission reactions occur in the reactor core, where fuel rods containing fissionable material such as uranium-235 undergo a controlled chain reaction. Neutron-absorbing control rods can be inserted or removed to regulate the reaction rate. If the control system fails, the fuel rods may overheat, potentially leading to a nuclear meltdown, a situation where the core's temperature escalates uncontrollably, causing the fuel to melt and risking the release of radioactive materials.