Testing techniques for simulating earthquake motion

A significant number of nuclear powered generating stations have been built or are under construction in order to meet the increasing demand for electrical power. Unfortunately, many of these stations are located in earthquake susceptible areas. In order to minimize failures of critical equipment or components during earthquakes, it is required that a large portion of such equipment be tested to simulated earthquake motions to insure that vital functions can be maintained to avoid malfunction of the entire power generating system, or, in case of failure, an orderly shut down sequence can be executed. The objective of this article is to present existing testing techniques applicable to the qualification of equipment to earthquake environments. The emphasis of the discussion will be centered in the areas of test criteria, exciter systems and control systems so that basic testing principles required to implement earthquake testing requirements can be fully understood. In addition, a list of selected references related to earthquake simulation testing is presented in the Bibliography section for further reference. (U.S.)