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
Office of Nuclear Reactor Regulation crisis zone in person in order to demonstrate that the dangers were not as high as many believed. These events occurred at approximately the same time as the beginning of the J. Samuel Walker term of service as the official historian of the NRC and are documented by him in "". Office of Nuclear Reactor Regulation The Office of Nuclear Reactor Regulation, usually known by the acronym NRR, is a subordinate part of the United States Nuclear Regulatory Commission. The Office should not be confused with the NRC's Nuclear Regulatory Research. The Office's current Director is William Dean. It has