Classification of Nuclear Power Plant Items and Quality Requirements on Design Extension Items

Adequate safety classification for nuclear power plant items is an important means to ensure good safety and economic performances of the plants. Classification theories and methods further develop with the continuous improvements in nuclear safety goals and plant design philosophy. It becomes a consensus that future nuclear power plants should be explicitly designed against certain severe accidents though their occurrences are considered extremely improbable, and therefore, the quality requirements on equipment expected to function under "beyond design basis" accident conditions becomes a focused topic of discussion.Considering both domestic and international experience, as well as the higher safety goal required for China’s new nuclear power plants and related development in other countries, relevant modifications are p roposed to be made to the current regulations and standards, and further, a set of equipment quality requireme nts is recommended.