Study On Nuclear District Heating Sino-russian Comparison And Basic Heat Load Optimization

With the rapid urbanization development in China,the demand for district heating energy continues to increase,and the pressure for energy saving and emission reduction has increased.At present,China is facing an urgent need to adjust the energy structure and improve the quality of the atmospheric environment.More attention has been paid to the related topics of finding effective,reliable and economical clean district heating energy source.Nuclear district is a clean energy source,and its advantages are environmental protection,high energy density and stability.At present,China's nuclear district heating technology is at initial phase,and a series of in-depth studies are urgently needed in related design,construction,operation management,standards and specifications.First of all,the development process of nuclear district heating technology between Russia and China were put in order.Russian nuclear district district heating was summirazed into five development stages,China has four types of nuclear district heating technology developed during different periods.The key technologies of nuclear district heating in Russia and their main technical parameters were analyzed,including the low-temperature nuclear district heating reactor AST-500,nuclear power plant steam turbine extraction,and the world's leading floating nuclear power plant.These technologies were compared with Chinese low temperature nuclear district heating reactor and nuclear power plant steam turbine extraction.It is pointed out that Russia's current nuclear district heating technology is mainly based on the nuclear power plant steam turbine extraction.Comparison of Russia and China's future nuclear district heating strategy policy were conducted.The long-distance heat supply network technology,that is closely related to nuclear district heating,was also compared and analyzed.Comparative study was conducted on the nuclear power plant ventilation technology standards in Russia and China,the relevant standards system of the two countries was sorted out,and the nuclear power plant ventilation technology standardization in China and Russia was carried out.Analysis and relevant suggestions for further improving of HVAC and fire protection standards of nuclear power plants in both countries were provided.Research shows that China and Russia are highly complementary in the field of nuclear district heating.Russia's mature nuclear power cogeneration technology and experience have a great reference value for China's future development of nuclear district heating.Secondly,the optimal basic heat load ratio of the low temperature nuclear district heating reactor was studied.Based on the analysis of the contradiction between the supply and demand of China's low-temperature nuclear district heating reactor,a method for determining the thermal load ratio of low temperature nuclear district heating reactor based on the reactor power adjustment range and thermal load duration time chart is proposed.When lowtemperature nuclear district heating reactor power adjustment range is 20%,taking the typical city in the northeast as an example,the optimal basic heat load ratio of the low-temperature nuclear district heating reactor is calculated to be 0.3-0.5.In response to the problem of low central heating load during non-heating period in China,measures to increase the thermal load factor of low-temperature nuclear district heating reactors were proposed,including interseasonal heat storage systems,combined heating and seawater desalination,and combined cooling and heating technologies.Thirdly,an optimization model for the thermalization coefficient of nuclear cogeneration is established based on relative primary energy saving(RPES),and the optimized basic heat load of nuclear cogeneration is studied.Through the comprehensive analysis of the evaluation indexes of conventional thermal power plants and nuclear power plants,the maximum relative primary energy saving of the nuclear power cogeneration system is used as the target function,and the optimization model of the thermalization coefficient of nuclear power cogeneration was established.The calculation methods of energy consumption and heat supply of the cogeneration system were established.Multi-factors and multi-levels orthogonal test analysis of the optimal thermalization coefficient of nuclear district combined heat and power system was conducted to determine the optimal thermalization coefficient of nuclear district combined heat and power system.The ranking of key influencing factors for 92 cities in northern China's district heating zone were analyzed based on the main influencing factors on the optimal thermalization coefficient of the nuclear power plant heating system.The research results show that,among the six main climate parameters,the dimensionless quantity ? of the heat load duration curve has the highest correlation with the optimal thermalization coefficient.The regression formulas of the optimal thermalization coefficient within the different ranges of different influencing factors were obtained.Without considering the annual heat load,comprehensively considering other main influencing factors,the optimal thermalization coefficient range of the nuclear power plant heating system based on relative primary energy saving model is 0.613-0.735.