Safety specifications for design of nuclear power plant
(Revised in 2016, approved and issued by the National Nuclear Safety Administration on October 26, 2016)
1 Introduction
1.1 Purpose
In order to realize the safe operation of nuclear power plants and prevent or mitigate the consequences of events that may endanger safety, this document specifies the design of structures, systems and components that are important for the safety of nuclear power plants, and the requirements that must be met by regulations and organizational processes.
This document is applicable to the analysis, verification and examination, technical support and nuclear safety supervision in the design, construction, operation and decommissioning stages of nuclear power plants.
1.2 Scope
1.2.1 This document specifies the requirements of comprehensive safety evaluation to determine the potential hazards that may arise in various operating conditions and accident conditions of nuclear power plants. The safety evaluation process involves two complementary technologies, i.e. deterministic safety analysis and probabilistic safety analysis. Various postulated initiating events must be considered in the analysis, including many factors that may affect safety individually or in combination. These events are of the following types:
(1) event originated from the operation of nuclear power plant;
(2) event caused by personnel behaviors;
(3) event directly related to the nuclear power plant and its environment.
1.2.2 This document does not involve general industrial safety which is extremely unlikely to affect nuclear safety and non-radioactive impact caused by the operation of nuclear power plant.
1.2.3 The nuclear power plant referred to hereof mainly refers to the onshore stationary nuclear power plant with water-cooled reactor, which is designed for power generation or other heating applications (such as centralized heating or seawater desalination).
1.2.4 The design of reactors of other types or adopting innovative technologies may refer to this document, but shall be subjected to careful evaluation and judgment.
2 Safety objective and defense in depth concept
2.1 Safety objectives
2.1.1 The basic safety objective is to establish and maintain effective defense against radioactive hazards in nuclear power plant so as to protect the people and environment from such hazards.
2.1.2 The following measures must be taken to achieve the basic safety objective:
(1) control the radiation exposure to personnel and the release of radioactive materials to the environment during operation;
(2) limit the possibility of events causing the reactor core, spent fuel, radioactive waste or any other radiation source of the nuclear power plant to get out of control;
(3) mitigate the consequences of the above events (if any).
2.1.3 The basic safety objective is applicable to all activities of nuclear power plants, including planning, site selection, design, manufacturing, construction, debugging, operation and decommissioning, as well as transportation of radioactive materials, management of spent fuel and radioactive waste, etc.
2.2 Radiation protection design
2.2.1 In order to achieve the basic safety objective, the radiation protection design must ensure that the radiation exposure in the nuclear power plant or the radiation exposure caused by any planned emission of radioactive materials from the nuclear power plant is lower than the specified limit value under all operating conditions, and may be as low as reasonably possible. At the same time, measures shall be taken to mitigate the radioactive consequences of any accident.
2.2.2 In order to achieve the basic safety objective, the radiation protection design must make all radiation sources of nuclear power plants under the control of strict technical and management measures. However, it neither rules out the limited exposure to personnel, nor the emission of radioactive materials permitted by laws and regulations from operating nuclear power plants to the environment. The above radiation and emission must be strictly controlled, meet the operating limits and radiation protection standards, and be as low as reasonably possible.
