Nuclear chain reaction between being slightly subcritical and slightly delayed-supercritical, but must always remain below prompt-critical. It is impossible for a nuclear power plant to undergo a nuclear chain reaction that results in an explosion of power comparable with a nuclear weapon, but even low-powered explosions due to uncontrolled chain reactions, that would be considered "fizzles" in a bomb, may still cause considerable damage and meltdown in a reactor. For example, the Chernobyl disaster involved a runaway chain reaction but the result was a low-powered steam explosion from the relatively small release of heat, as compared with a bomb. However, the reactor complex
Jōyō (nuclear reactor) Jōyō (nuclear reactor) It was made with the purpose of doing tests on and advancing the development of that type of reactor, as an irradiation test facility for construction materials. It also does tests with the nuclear fuel as well as activation experiments. The reactor has gone through 3 different core changes. The current core provides the neutron flux of 4×10 cms for E>0.1 MeV. After an incident in 2007, the reactor is suspended for repairing, recovery works were planned to be completed in 2014. Following the closure of the unsuccessful follow-on fast breeder reactor Monju in 2016, a decision