Quantification Of Radiation Dose In Case Of An Accident Through Development Of Atmospheric Dispersion Modelling Code

In case of any nuclear power plant accident,radiation leakage to the atmosphere and the subsequent radiation exposure to the public and safety workers becomes an immediate concern.Radiation dose assessment is done to evaluate the damage and potential risks to biological life near the plant and thereby,formula emergency evacuation plans.Atmospheric dispersion models are used to calculate the radionuclide air concentration and organ dosage.An atmospheric dispersion model based on Gaussian plume model has been developed in MATLAB to calculate radionuclide air concentration,TEDE,ground deposition and ground shine dosage rate.Several input parameters/variables such as source term activity,mixture of radionuclides,meteorological conditions,source and receptor height,terrain types,atmospheric stability classes,surface roughness,inversion layer height,buoyant and momentum plume rise,breathing rate,stack and ambient temperature,and respirable and non-respirable deposition velocities have been included.Onsite and regional input data information related to topography and meteorology of K2/K3 nuclear power plant is applied with the latest IAEA Post-Fukushima Guidelines to the model.Regarding transport,deposition and diffusion of radionuclides,the model calculates time-integrated air concentration,submersion,inhalation and ground shine exposure,TEDE,ground deposition,and ground shine dosage rate.The developed model also gives detailed information regarding exposure to human organs and separate information from each radionuclide from the mixture source term about thyroid and bone marrow dosage.Results show that sheltering and iodine tablet(ITB)is needed to avoid radiation damage to thyroid due to I-131 radiation while exposure to bone marrow falls within the IAEA safety criteria of 1Sv at a distance of 1.4km from the radionuclide source.All results are stored in Microsoft Excel files and graphs against downwind distance are plotted.Results have been compared with a widely used reference standard code HotSpot and margin of error is calculated.The comparisons prove that the results obtained from the developed model are similar and can be used for further use regarding similar studies.It is concluded that the results follow all the trends visible from the results of HotSpot and the results are accurate.The margin of error is less than 2 percent.