Nuclear reactor

A nuclear reactor is a complex physical facility in which controlled nuclear reactions, generally involving criticality (nuclear), take place for a variety of purposes. These purposes may include heat generation for electrical generation, marine propulsion, or heating industrial plants; the preparation of radioactive isotopes for use in nuclear medicine, industrial testing, or creating controlled sources of radiation; production of nuclear materials such as plutonium or tritium; or making materials temporarily radioactive for procedures such as neutron activation analysis. While there can be some overlap of functions, larger reactors tend to be optimized for a single purpose; part of the design failures causing the Chernobyl Disaster were that the reactor tried to be equally effective for electric power and plutonium generation.