The purpose of this booklet is to provide a basic understanding of nuclear fission energy and different fission reaction concepts. Topics discussed are: energy use and production, current uses of fuels, oil and gas consumption, alternative energy sources, fossil fuel plants, nuclear plants, boiling water and pressurized water reactors, the light water reactor fuel cycle, enrichment, reprocessing, the breeding process, breeder reactor design, the breeder reactor fuel cycle, and breeder reactors in the United States. Each topic is accompanied by an illustration or diagram to aid understanding. A section of additional information describes the history of nuclear power in the United States, and nuclear plants throughout the world. A glossary defines basic terms used to describe the fission process, the fuel cycle, and nuclear reactors. This pamphlet is suitable for use with secondary school students. (LP)