ABSTRACT
The basic process used in today’s nuclear power plants is the fission of heavy element nuclei. In this process, a carefully-controlled fission reaction generates heat to produce steam to power conventional turbines for electricity generation. An alternative nuclear reaction, fusion, is the same process by which the sun’s radiation is generated. Its mechanism has been under investigation for a long time, but is not likely to reach commercial feasibility for many years to come. This chapter will therefore concentrate on the power derived from fission, which is a commercially available means of generating power that has been developed and employed for many years in several countries. In this type of nuclear reaction, a power source called a nuclear reactor captures the energy from the fission process as heat, which is then transferred to a working fluid that can be used to generate electricity, similar to the Rankine cycle in a coal-fired power plant. The primary fission fuel currently used in a majority of nuclear power plants is Uranium-235 (235U)—an isotope of the element Uranium-238 (238U). Uranium is a widely available element in the Earth’s crust, and it occurs naturally as an ore containing about 99% 238U and about 0.7% of the isotope 235U in all natural uranium deposits. When 235U is fissioned in a reactor, it provides about one megawatt day of energy for each gram of 235U that is fissioned.
