Reactor Site Atmosphere Filled With Problems And Optimize The Planning Problems Of The Atmospheric Emission Limits

Qinshan area will become one of nuclear power bases with mhlti-reactor on onesite in our country with the developmen of nuclear power. As for this situation, theNational Environmental Protection Agency Put forward "the unified management forfour aspects" in order to enhance the management of nuclear power, i.e., unifiedmanagement of release limits, unified management of environmental monitoring forradioative effiuents, unified management of accident emergency and unifiedmanagement of radioactive waste. The atmospheric dispersion and optmiticalplanning of gaseous effluence discharge limits for multi-reactOr sites of QinshanNuclear Power Engineering is described in thes paper through calculating andanalysing the data obtained from field observations, wind tunnel modellingexperiments and numerical simulations.The studies on correlation of meteorological elements in multi-reactor sites arepaid great attenion in environmental impact assessmen of nuclear power plan (NPP).On the basis of the data obtained from the field observations and wind-tunnelmodelling, the calculations and comparisons on probability distribution and density,linear correlation analysis of time series, conditional probability density and so on ofwind speeds and directions between various sites are made with the aid of statisticalanalysis of time series, and changes of these variables with heigh andrepresentiveness of observation period of meteorological data are also discussed.The results indicate that the background wind field determines macroscoPically thebasic metorological features in one area. The correlation level depends on theamplitude of the locally topographic disturances. The meteorological elements at oneposition, such as wind speed and wind direction, cannot be directly used as those atthe another position in complex terrain without systematic correlation analysis. Inaddition, it should consider tha atmospheric stability class is different between thesites in complex terrain.The problems of estimating the joint frequency and annual atmosphericdispersion factr for a new NPP can be solved by establishing correlation ofmeteorological elements between the new NPP and an opefating NPP based on ameteorological correlation experiments and using available meteorologicalobservation data of the operating NPP. The results indicate that it is more accurate toestimate joint frequency by using probability matrixes than frequency matrixes. Ifprobability matrixes are modified in the light of annual frequency distributions ofwind direction and wind speed set, joint frequency and annual atmospheric diffusionfactor are better estimated by using correlation matrixes obtaned with the shorterperiod of meteorological observation data.Studies on flow and dispersion in complex terrain and around buildings havebeen a subject of increasing debate and interest. The characteristics of flow incomPlex tCrrain are investigated through exPerimellts conducted in an environmelltalwind ttnmel. The wake strUctUre behind hills is divided into Wak shadow region,strong wtulence region and recirculating now region. The maximum perturbations inmean velocity and velocity variances caused by hills decay with distance from hills,the decay relations of which are obtained by fitting the exPerimental data. AlthOughthe flow peedations in comPlex terrain are obviously different frOm those around"regular" conical hills, the decay relations Obtained frOm the present study aremacroscOPically consistent with those about conical hills. In addition, that windprofiles are exPressed as conventional logarithInic form and rePonential fOrm willcause great ermr because the profiles vny largely in comPlex terrain, esPecially in thewat.The charaCtestics of diSPesion in comPlex terran are investigated thrOughcombining wind tUnnl modelling expements and particle random Wak simulations.The results indicate that on the one hand the ditheion pararnters increase...