1.0.1 This code is formulated with a view to implementing the laws, regulations and technical economy policy of the construction of relevant national nuclear power plant, meeting the safety requirements for the design construction and operation of nuclear power plant engineering, unifying the content, method, depth and technology requirements of hydrological survey, analysis and calculation, guaranteeing the design technique level and quality of engineering hydrological survey, and achieving safety and usability, technical advancement and economic rationality.
1.0.2 This code is applicable to the hydrological survey, analysis and calculation work of water supply-source, flood control at plant site, fluvial process and beach stability of fixed commercial land nuclear power plant engineering of various reactor types.
1.0.3 Local measured hydrological information and survey information shall be the main criterion for the hydrological survey, analysis and calculation of nuclear power plant engineering. Measured information of adjacent or similar basin may be selected for referential evidence where measured information has a shortage, but the representativeness of reference station information for engineering point shall be analyzed; observation station shall be established adjacent to engineering point where necessary, and observation items, content, method and cycle shall be carried out according to the characteristics and requirements of hydrological survey of nuclear power plant.
1.0.4 The basic hydrological information, adopted in hydrological survey, analysis and calculation of nuclear power plant engineering shall be analyzed in terms of the reliability, consistency and representativeness. Method selection and parameter calibration in the process of calculation and analysis shall be carried out according to local hydrology and related condition; the safety and rationality of calculation and analysis shall be guaranteed.
1.0.5 During construction and operation phase of nuclear power plant, where historical infrequent hydrological event happens, design organization shall timely survey and collect relevant information to recheck the original calculated result, correct original calculated result where necessary and propose countermeasures jointly with relevant personnel.
1.0.6 Hydrological survey, analysis and calculation of nuclear power plant engineering shall not only comply with this code, but also comply with those specified in the current relevant standards of the state.
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2 Terms
2.0.1 Nuclear safety
Completing the correct operation condition and accident prevention or relieving the accident consequence so as to protect the site personnel, the public and environment from excessive radiation hazards.
2.0.2 Safety system
As an important system for safety, it is used to ensure an safe shutdown of the reactor, to discharge the residual heat from reactor core or to restrict the consequences of anticipated operation event and accident condition.
2.0.3 Design basis
Design parameter value determined for reaching the design standard of nuclear safety important items.
2.0.4 Deterministic method
It's a method that the majority of parameters and their values may be determined by mathematical method and clarified through physical relationship.
2.0.5 Probabilistic method
Probability distribution model is adopted to analyze hydrographical features sequence and calculate design parameter.
2.0.6 Design basis flood
The flood selected for determining the design basis of nuclear power plant.
2.0.7 Residual heat
The sum of heat generated by fission after radioactive decay and shutdown and that stored in the reactor structural material and heat transfer medium.
2.0.8 Final heat sink
The atmosphere or water or the combination of both accepting the residual heat discharged by nuclear power plant.
2.0.9 Hydrological survey
On-site information collection, reconnaissance, investigation and measuring etc. conducted to master basic hydrological information.
GB/T 50663-2011 The following standards are cited：
