In the following, the names of U.S. federal regulations will be abbreviated in the standard way. For example, "Code of Federal Regulations, Title 10, Part 50, Section 59" will be given as "10CFR50.59".
A list of all U.S. federal regulations is provided at the Government Printing Office Site, or 10 CFR can be found at the Nuclear Regulatory Commission (NRC) website in their public document section .
Nuclear materials and use of those materials (see also Radioactive Materials) typically requires a license of some sort from the government(s) in which the activities will be conducted. In the United States, licenses are issued either by the U.S. Nuclear Regulatory Commission, or in some cases by the individual states who have been delegated authority for some licensing activities, e.g. Arizona ([Arizona Radiation Regulatory Agency]).
Countries other than the U.S.A. use different licensing schemes, typically at the national level, with formal or informal participation at the local government level. For example, in Great Britain, the Health and Safety Executive  oversees licenses and nuclear safety.
In the United States, recent licensing activities have been focused on the next generation of nuclear reactors being planned. Efforts are underway to prepare the documents required by the U.S. Nuclear Regulatory Commission, including Environmental Reports (also known as an Environmental Impact Report) and Final Safety Analysis Reports, consistent with 10CFR50, 10CFR51 and 10CFR52. The regulations were revised to permit one-step licensing in an effort to remove regulatory risk and better define the rules and processes needed to obtain a license for a nuclear power plant in the United States.
The NRC now lists  about 25 individual nuclear power plants in the planning stages. Many of these have already begun the license preparation activities. Most of the facilities are planned for sites that already are home to at least one existing nuclear power plant.