Chapter 2 of the book provides an in-depth historical background of regulations related to the licensing of nuclear power plants. At the time (circa 1952), only experience the AEC had was related to the small-scale government reactors and the demonstration reactors (see Table 1.1 of Chapter 1). With this knowledge and help from the research conducted at the national laboratories (e.g., Argon, Idaho), the AEC embarked on developing regulations that could apply to the commercial power reactors. One of the constraints imposed by the U.S. Congress was that the regulations should not be so restrictive that they would discourage the development of a private nuclear industry. At the same time, the regulations should be adequate to protect the public health and safety. During the period 1954 to 1962, the AEC’s review of the construction permit applications and development of regulations, were conducted side by side. By 1962, the AEC developed workable regulations that were used by the applicants of construction permit for nuclear power reactors.