Chapter 8 – Power Reactors

Publisher Summary The first nuclear reactor was operated briefly by Enrico Fermi and his associates at the University of Chicago on December 2, 1942, less than 4 years after the discovery of nuclear fission. Under wartime pressure, reactor technology continued to develop rapidly, and only 1 year later a 3.8 thermal megawatt (MWt) research reactor began operation at Oak Ridge. At present, about 1000 land-based reactors have been built and operated in various parts of the world. These include reactors built for research, as well as production of power, radioisotopes, and plutonium. More than 200 vessels of the American and Russian navies have been powered by nuclear reactors. Great impetus to the development of a civilian reactor industry came from the first United Nations International Conference on the Peaceful Uses of Atomic Energy, which took place in Geneva in the fall of 1955. The health physicist, physician, engineer, or health officer concerned with the effects of reactors on the environment should possess a general understanding of those aspects of design that may affect the kind and quantity of radioactive effluents discharged to the environment under normal and abnormal conditions. It is also important to appreciate the basic methods used to prevent uncontrolled release of radioactivity to the environment and to understand the monitoring activities required to assure compliance with the applicable limitations on discharges of radioactive wastes. Contemporary reactors, with only a few exceptions, use either natural uranium or uranium in which the amount of isotope 235 has been enriched. The amount of 235U enrichment may vary from 0.7% to more than 90%, but the fuel in most civilian power reactors is enriched to about 3%. Plutonium can also be used as a fuel for reactors.