DESIGN AND DEVELOPMENT OF A RADIOECOLOGICAL DOMESTIC USER FRIENDLY CODE FOR CALCULATION OF INDIVIDUAL /COLLECTIVE RADIATION DOSES AND CONCENTRATION DUE TO RADIONUCLIDES AIRBORN RELEASE DURING THE ACCIDENTAL AND NORMAL OPERATION IN NUCLEAR INSTALLATION

A domestic user friendly dynamic radiological dose and model has been developed to estimate radiation doses and stochastic risks due to atmospheric and liquid discharges of radionuclides in the case of a nuclear reactor accident and normal operation. In addition to individual doses from different pathways for different age groups, collective doses and stochastic risks can be calculated by the developed domestic user friendly KIANA Advance Computational Computer Code and model. The current Code can be coupled to any long-range atmospheric dispersion/short term model which can calculate radionuclide concentrations in air and on the ground and in the water surfaces predetermined time intervals or measurement data.A deterministic dose calculation model called as user friendly KIANA Advance Computational Computer Code has been designed and developed for this study in first time in our country. For the dose assessment, all exposure pathways have been implemented as follows:Transfer of radionuclides through food chains and the subsequent internal-exposures of humans due to ingestion of contaminated foodstuffs- Internal exposure due to inhalation of radionuclides during passage of cloud and from re-suspension of deposited radionuclides- External exposure from radionuclides in the passing cloud- External exposure from radionuclides deposited on the ground. Developed code is implemented in Visual Basic. Editable parameters are number of radionuclides, of the whole area modeled,concentration and deposition outputs of an atmospheric dispersion model or measured air concentration and deposition data in days, and time interval of dose calculation in days and in years. Current User Friendly KIANA Advance Computational Computer Code can perform modeling well for unlimited isotopes, 70 years, 13 food stuffs and pasture, 8 animal products, 4 different age groups, i.e. infant, child, teen and adult, maximum and average individuals in terms of food consumption habits, correction coefficients for gamma dose rate and time spent outdoors. The Current user friendly KIANA code can produce individual dose results annually for each isotope and pathway, and the sum for all isotopes and pathways as well, and collective total dose results. The model in Current user friendly KIANA code can also produce monthly activity results in grass and animal food products, activity concentrations results of agricultural food products at each harvest year after the accident and during normal operation, and total risk results might be calculated as well. External input data files include age dependant food consumption rates, breathing rates and reduction factors for external radiation for maximum and average individuals, feedstuff intake rate of animals, storage times and processing factors of food products, translocation factors for plants, plant yields, distribution coefficients and fixation rates of radionuclides, soil-plant and feed-animal transfer factors, biological transfer rate for animal products.Since the Chernobyl accident, there had been an increase in real world data to assess the capabilities of softwares, which are developed to calculate radionuclide concentrations in the environment and doses to human. Therefore, data related to the final safety analyze report(FSAR) of the typical WWER-1000 and Chernobyl accident was used to validate the developed Kiana Advance Computational Code. The validated developed Code( software) was then used to calculate radiological consequences in the case of hypothetical severe accidents and normal operation at typical WWER-1000 such as BNPP-1 and Akkuyu and Sinop NPPs in Turkey and IRAN. The accident scenario was based on Fukushima Daiichi NPP accident. The newly developed KIANA Advance Computational Computer Code was run for different release times, and it was turned out that meteorological pattern as well as vegetation cycles of the plants were influencing doses to humans. Ingestion of radionuclides in foods can be an important contributor to the total dose received by an individual or population group.An estimate of the radionuclide concentration is needed to assess such doses . This research will be described a generic methodology to calculate the concentration of radionuclides in human food crops, and animal produce and in surface waters . this paper will be consider the important parameters such as: (a) Deposition by dry or wet processes;(b) Initial interception and retention by vegetation surfaces;(c) Translocation to the edible tissues of vegetation;(d) Post-deposition retention by vegetation and soil surfaces;(e) Uptake by roots;(f) Adhesion of soil particles on to vegetation surfaces;(g) Direct ingestion of surface soil by humans or grazing animals;(h) Transfer of radionuclides in soil, air, water and vegetation into the milk and meat of grazing animals; (i) Transfer of radionuclides in surface water to the terrestrial system by spray irrigation; (j) Transfer of radionuclides in surface water to sediment and to aquatic biota either explicitly or implicitly. Radionuclides discharged into the aquatic environment are also assimilated by living organisms. Some of the assimilated radionuclides are passed along the aquatic food chains and may eventually reach to humans. User Friendly Domestic KIANA Advance Computational Computer Code are used for dose assessments to simulate the transport of radionuclides in aquatic environments and air concentrations. Current Code that describe the transport of radionuclides from liquid discharges to aquatic foods. This paper will be described the generic methods for estimating radionuclide concentrations in water (and sediment) as well as in Rivers, Estuaries, Coastal waters, Small lakes, Large lakes that may be calculated for specific locations where members of hypothetical critical groups could use this water for drinking, fishing, irrigation or swimming, and could use the sediment for recreational or agricultural activities. These locations (at a specified distance x from the point of discharge) are selected to represent the nearest point where water usage is conceivable during the projected lifetime of an operating nuclear facility. The methodology also includes simple processes to estimate default dispersion coefficients, river flow conditions and the coastal current, if site specific values are unavailable.The doses incurred due to a severe accident at Akkuyu NPP were calculated as 3.374 mSv 1 year after the accident, and the lifetime doses will be 9.706 for adults having average habits; the doses in the case of Sinop NPP accident have been found out to be more than that of Akkuyu NPP accident. Cs-134, Cs-137 and I-131 were identified as the most dose contributing isotopes, and cereals, cow milk, chicken, fruits, lamb, beef, fruit vegetables and root vegetables were the most dose contributing foods respectively(Figures 1 up 9). For the maximum deposited grit found out as a result of simulation of Akkuyu NPP accident, and for the related parameters of most dose contributing isotopes and foodstuffs, uncertainty analysis was performed by LHS to predict uncertainties in the doses and activity concentrations for all pathways will be considered . Furthermore, sensitivity analysis was also conducted by again LHS of the aforementioned parameters and the outputs were processed by correlation techniques to find out most influencing parameters on lifetime and short-term doses. It can be concluded that soil-plant transfer factors for Cs have a big influence on the lifetime(Collective) dose results, feed-animal transfer factor for Cs for cow milk and reduction factors for external radiation, beef and grain consumption amounts have also the high effect on lifetime doses. For the short term doses, cow milk transfer factor for iodine and interception factor for the grass are also influential parameters. The design of the User Friendly KIANA code is flexible such that it can be adopted anywhere for any nuclear power plant site with suitable modifications to the database.

Keywords:

Dynamic software , environmental transfer , radionuclide , nuclear accident , Concentrations Chernobyl , dose , risk , uncertainty , Exposure pathways , user friendly , KIANA Advance Computational Computer Code , long-range transport model , Short-range dispersion models , Gaussian dispersion equations , Dose assessment methodology