What are the chemical reactions that happen when a nuclear plant explodes?

Answer 1

That would depend on what is ignited. If you are referring to events such as the accident in Chemobyl. Upon meltdown, the nuclear core which is partly composed of graphite burned releasing radioactive smoke. There must be many chemical combustion reactions of all sorts happening depending on what has caught on fire. The major concern is the radioactive debris from the core spewing into the environment. There would not be a large explosion such as a nuclear bomb because the uranium used in the core is not enriched enough to detonate.

Answer 2

When a nuclear plant explodes, the main chemical reactions involve the release of high levels of radioactive material into the environment. This can include the fission of uranium or plutonium atoms, resulting in the production of various radioactive isotopes. The explosion can also generate heat that may lead to chemical reactions between the nuclear fuel and surrounding materials, potentially causing further releases of radioactive substances.