1.0.1 This code is formulated with a view of carrying out such guidelines as “earthquake prevention first” and “civil nuclear facility safety first”, realizing the safe operation, high quality, state-of-the-art technologies, economic feasibility of the nuclear power plants.
1.0.2 This code is applicable to the seismic design of nuclear safety-related items in pressurized water reactor (PWR) nuclear power plants, where the peak acceleration of the ultimate safety ground motion is not larger than 0.5g.
Nuclear power plants, designed according to the provisions, shall run well when being affected by the seismic motion equal to the operational safety ground motion; they also shall ensure the reactor coolant pressure boundary intact, the reactor safely shutdown and maintain safe off-state, and the spillovers of the radioactive substances not exceed the national limitation when being affected by the ultimate safety ground motion.
Note: ① Items in this code are referred to containments, buildings, structures, underground structures, pipes, equipments and other related parts.
② G is the acceleration of gravity, with the value for 9.81m/s2.
1.0.3 The items of the nuclear power plants shall be divided into the following three classes according to the significance of their requests for nuclear safety:
(1) Class Ⅰ items: the nuclear safety-related important items in the nuclear power plants, including items which can directly or indirectly cause accidents after damaged; items needed to ensure the reactor be able to safely shutdown and maintain off-state as well as remove the residual heat; items needed to alleviate the damages caused by the nuclear accidents during and after the earthquake, as well as other items which will endanger the above mentioned items when being damaged or de-functioned.
(2) Class Ⅱ items: nuclear safety-related items (in addition to class Ⅰ items) in the nuclear power plants and nuclear safety-irrelevant items which can endanger the above named items when being damaged or de-functioned.
(3) Class Ⅲ items: nuclear safety-irrelevant items in the nuclear power plants.
Note: classⅠ, Ⅱ and Ⅲ items may be divided according to the examples of Appendix A.
1.0.4 The seismic design of all the items shall be in accordance with the following seismic protection standards:
(1) ClassⅠ items shall, simultaneously, adopt the operational safety ground motion and the ultimate safety ground motion for seismic design;
(2) Class Ⅱ items shall adopt the operational safety ground motion for seismic design;
(3) Class Ⅲ items shall be in accordance with the national current related codes for seismic design.
1.0.5 As for the seismic design of the nuclear power plant, not only the requirements stipulated in this code, but also those in the current relevant ones of the nation shall be complied with.
