Book excerpt: This book looks at Generation IV (GEN IV) nuclear reactor design and the technology known as nuclear micro reactors that is currently under development. Coverage includes the advantages of nuclear micro reactor applications as sources of renewable energy, their use in military applications and Department of Defense requirements, and the nuclear industry’s trend toward the design of small and micro reactors. Nuclear micro reactor safety, security issues, and cost concerns are also explored. The book will provide scientists, engineers, and students with valuable guidance on the fundamentals needed to understand the research and development of the next generation of nuclear technologies.