1　General

1.0.1　This code is developed to implement national laws，regulations and technical and economic policies on the construction of nuclear power plant，meet the safety requirements for the design，construction and operation of nuclear power plant，unify the contents，methods，depth and technical requirements of engineering hydrologic survey，analysis and calculation for nuclear power plant，ensure the technical level and quality of engineering hydrologic survey and design for nuclear power plant to make it safe，applicable，technically advanced and cost-effective.

1.0.2　This code applies to the hydrologic survey，analysis and calculation for the water source，flood control，riverbed evolution and beach stability of land-based stationary nuclear power plants with various reactor types.

1.0.3　Engineering hydrologic survey，analysis and calculation for a nuclear power plant shall be carried out mainly based on locally surveyed hydrologic data and investigation data.Where such surveyed data is unavailable，the surveyed data obtained from reference stations in neighboring or similar river basins may be used for reference，but the representativeness of such data with respect to the project site shall be analyzed.Where necessary，observation stations shall be set up near the project site，with the observation items，contents，methods，and periods determined according to the characteristics and requirements of hydrologic survey for the nuclear power plant.

1.0.4　Basic hydrologic data used for engineering hydrologic survey，analysis and calculation for a nuclear power plant shall be analyzed for reliability，consistency and representativeness.Method selection and parameter calibration during calculation and analysis shall be carried out according to local hydrologic and other relevant conditions，and shall ensure the safety and rationality of calculation and analysis results.

1.0.5　During the construction and operation of a nuclear power plant，if historically rare hydrologic events occur，the design institute shall carry out survey and data collection in a timely manner，review，and if necessary，correct original calculation results，and propose countermeasures in joint efforts with relevant personnel.

1.0.6　In addition to this code，the hydrologic survey，analysis and calculation of a nuclear power project shall also comply with relevant national standards in force.