Depending on the regulatory system, a guide may or may not be mandatory; it may simply demonstrate how a certain requirement can be achieved. In some regulatory systems, the licensees can take advantage of the regulatory guidance but they may use alternative ways to demonstrate the achieve­ments of the goals established in the requirements. These guides also provide information on data and methods to be used in assessing the ade­quacy of the design and on analyses and documentation to be submitted to the regulatory body by the licensee. Technological advances, research and development work, relevant operational lessons learned, and institutional knowledge can be valuable and useful when revising the guides. The man­agement system also reflects clearly the approach to be used to review and revise guides.

4.1.5 Industrial standards and guidelines

The regulatory body also bases its regulations and guides on national leg­islation and utilizes existing national regulations or industrial standards (e. g. ASME Code) in areas relating to or adaptable to nuclear power plants as its initial sources of information.