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The LIETDOS-BIO assessment approach to Environment protection from ionizing radiation T. Nedveckaite, D. Marciulioniene Institute of Physics, Savanoriu.

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Presentation on theme: "The LIETDOS-BIO assessment approach to Environment protection from ionizing radiation T. Nedveckaite, D. Marciulioniene Institute of Physics, Savanoriu."— Presentation transcript:

1 The LIETDOS-BIO assessment approach to Environment protection from ionizing radiation T. Nedveckaite, D. Marciulioniene Institute of Physics, Savanoriu 231, Lt-2058, Vilnius, Lithuania, E-mail: tatjana@cablenet.lt;tatjana@cablenet.lt Institute of Botany, Žaliųjų ežerų 49, LT-2021 Vilnius, Lithuania, E-mail: dmarciulione@yahoo.com Institute of Physics, Institute of Botany Lithuania

2 Ignalina NPP with decommissioning, spent fuel storage and waste disposal problems; Maisiagala RADON type radioactive waste repository amongst others with earlier (1963-1973) military radioactive waste from Lithuania, Kaliningrad and Belarus. Estonia Russian Federation Belarus Poland Lithuania Latvia INPP Kaliningrad Maisiagala repository

3 Ignalina NPP, Druksiai Lake – cooling pond, spent fuel storage RSR – rain sewage release, Intake - cooling water intake, Release - cooling water release, PFoHE - purification facility of the household effluents of INPP and Visaginas, HSS – household sewerage release after biological treatment, SFSF - Spent Fuel Storage Facility.

4 The sampling points in Ignalina NPP cooling pond-Druksiai Lake

5 The spatial pattern of activated corrosion products 54 Mn and 90 Co in bottom sediments of Druksiai Lake. The highest activity concentrations correspond to sampling points: 2-sewerage outflow and 4-cooling water outflow. Other monitoring radioniclides and heavy metals: 54 Mn, 60 Co, 137 Cs, 90 Sr, 210 Pb, 210 Po, 238 U, 226 Ra, 232 Th Pb, Cd, Cr-VI, Ni, Cu, Zn-II, Zn

6 The projected Ignalina NPP decommissioning low-level repository sites

7 MAISIAGALA radioactive waste repository

8 Tritium in underground water in close vicinity of the repository reservoir (January-March 2007) Borehole No.

9 LIETDOS and LIETDOS-BIO – a software to calculate the radiological dose for human and non-human biota due to the presence in LITHUANIA radiation safety problems

10 LIETDOS –segmental atmospheric diffusion-convection model-code tested using data on I-131 released from Hanford (BIOMASS)

11 LIETDOS-human exposure model used for t he regulating document in Lithuania LAND 41-2001 : “Limitation of Radioactive Discharges from nuclear facilities and Order of Issuance of Permits for Discharges” Nedveckaite T., Motiejunas S., Kucinskas V., Mazeika J., Filistovic V., Jusciene D., Maceika E., Morkeliunas L., Hamby D.M. Environmental releases of radioactivity and the incidence of thyroid disease at the Ignalina Nuclear Power Plant. Health Physics, Vol. 79, No. 6, 666-684 (2000)

12 LIETDOS-BIO model a tool for calculating radiation doses to Freshwater and Terrestrial Biota with input file that is subsequently read by MCNPX MCNPX code Source (nuclide) EcosystemOrganisms/reference organisms Dynamic/steady-state transfer modelling Radionuclide concentration in medias Internal radionuclide concentration Preparing MCNPX input file for DCC calculations External dose (rate) Crystal Ball Total dose (rate) DCC calculations Internal dose (rate) Weighting General/site-specific parameters

13 LIETDOS-BIO code LIETDOS-BIO code is designed to be consistent with MCNPX code. MCNPX is commonly used general purpose radiation transport code that tracks all particles at all energies for internal and external exposure of any geometry organisms calculation. LIETDOS-BIO code is designed to be consistent with Crystal Ball software (Crystal Ball is a software for uncertainty analyses) for statistical calculation approaches. EXPERT CONTROLLED INFORMATION This is a limited distribution unclassified documents with code and may not be given to other persons. LIETDOS-BIO code Libraries and Data Bases: Nuclides Library - Electron, Positron, Beta, Alpha and Gamma Energy's data (ICRP 38) Reference Organisms Library:Terrestrial and Freshwater Ecosystems Concentration ratios (CR) – 3 Data Bases Partitioning coefficients (K d ) Library and etc.

14 LIETDOS-BIO (3 CR Data Bases) Site-specific radionuclide CR distribution-geometric mean values : Data Bases No. 1. Generic radionuclide CR values (FASSET, ERICA, BWG Ex 2 CR values): Data Bases No. 2. Stable nuclide (heavy metals) CR values (ERICA, site- specific). As demonstrate presented picture after the Chernobyl accident stable CR value may be used after few years: Data Bases No. 3.

15 FRESHWATER ECOSYSTEM 90 Sr CR for different type of Macrophytes – site-specific values Based on these data statistical CR approach has been used

16 The distribution of site specific Sr-90 CR values (macrophytes) involved in DB Nr 1

17 Co-60 CR (FW) site-specific distribution (macrophytes): LIETDOS-BIO site-specific DB (example) Statsistics:Value Trials20000 Mean8.61 Geometric Mean3.87 Median3.565 Mode--- Standard Deviation17.114 Variance292.875 Skewness7.81 Kurtosis115.80 Coeff. of Variability1.99 Range Minimum0.008 Range Maximum544.488 Range Width544.480 Mean Std. Error0.121

18 TERRESTRIAL ECOSYSTEM Plume of the Chernobyl accident formation by meteorological conditions for instantaneous releases on dates and times (GMT) indicated

19 Aerial Gamma - Spectrometry Test Results. Spots Denote Areas Where the Density of Cs-137 is at least 3700 Bq/square meter (the first contour), with a Contour-spacing of 1100 Bq/m 2

20 Soil Cs-137 activity distribution Bq/kg, 1986-1996 Lithuania o StatisticValue Trials10 000 Mean12.4 Median12.28 Mode--- Standard Deviation1.57 Variance2.47 Skewness0.44 Kurtosis3.4 Coeff. of Variability0.13 Range Minimum7.28 Range Maximum19.83 Range Width12.56 Mean Std. Error0.02

21 The distribution of site specific Cs-137 CR values involved in DB Nr 1 (Wild boar) Trials10 000 Mean2.41 Geom. Mean2.37 Median2.36 Mode--- Stand. Deviation0.46 Variance0.21 Skewness0.61 Kurtosis3.72 Range Minimum1.26 Range Maximum4.98

22 Internal Dose rate calculation Biota activity concentration and internal dose rate was calculated as follows:

23 Crystal Ball statistical technique was used with 10 000 number of trials and the Latin Hypercube sampling method. An example: Forecast: Co-60 Internal dose rate (macrophyte) Trials20000 Mean2.83E-04 Geometric Mean2.07E-04 Median2.07E-04 Mode--- Standard Deviation2.63E-04 Variance6.90E-08 Skewness3.47 Kurtosis28.18 Coeff. of Variability0.93 Range Minimum9.15E-06 Range Maximum5.61E-03 Range Width5.60E-03

24 External dose rate calculation External dose rate from sediment (FW) : External dose rate from sediment (DW):

25 An example of model for MCNPX code DCC calculation - fish (ellipsoid on sediment) in the middle of water cylinder 10 cm R = 100 cm 5 cm H w = 100 cm Water Sediment Fish W f = 60 cm H f = 10; D f = 5 cm H c =(10 +2 l); D c = (5 +2 l) cm W c = (60 + 2 l) cm

26 An example of model for MCNPX code external exposure DCC calculation: fish (ellipsoid) in the middle of water cylinder W f = 20 cm R = 100 cm 50 cm H w = 100 cm 10 cm H f = 12; D f = 4 cm Water Sediment Fish H c =(12 +2 l); D c = (4 +2 l) cm W c = (20 + 2 l) cm

27 An example of model for MCNPX code DCC calculation - rooted submerged hydrophytes  = 1 cm R = 100 cm H w = 10 0 cm 10 cm Water Sediment Plant

28 An example of model for MCNPX code DCC calculation - unrooted submerged hydrophytes  = 10 cm R = 100 cm H w = 10 0 cm 10 cm h = 0.2 cm Water Sediment Plant h 0 = 0.1 cm

29 Crystal Ball statistical technique was used with 10 000 number of trials and the Latin Hypercube sampling method. An example: Forecast: Co-60 External dose rate (macrophyte) Trials20000 Mean1.38E-02 Geometric Mean9.72E-03 Median9.73E-03 Mode--- Standard Deviation1.39E-02 Variance1.93E-04 Skewness4.23 Kurtosis42.67 Coeff. of Variability1.01 Range Minimum3.57E-04 Range Maximum3.39E-01 Range Width3.38E-01 Mean Std. Error9.83E-05

30 LIETDOS-W subroutine Taking into account tritium activity concentrations in the Ignalina Lake water and groundwater as well as groundwater activity in the vicinity of Maisiogala repository the LIETDOS-W code was developed to predict freshwater BIOTA exposure. LIETDOS-W code was tested during Perch Lake scenario (EMRAS working group on Modeling of tritium transfer to biota and man).

31 Freshwater HTO Biota OBT Biota HTO Sediment Layer HTO LIETDOS-W subroutine Steady-state tritium transfer modelling LIETDOS-BIO

32 LIETDOS-W: HTO and OBT concentrations in clams (EMRAS TWG Pearch Lake scenario: L – LIETDOS-W data) HTO concentrations in clams. The model predictions are shown as solid diamonds with the vertical lines representing 95% confidence intervals as estimated by the modelers. The solid horizontal line is the observation with the 95% confidence interval indicated by the dashed lines. OBT concentrations in clams. The model predictions are shown as solid diamonds with the vertical lines representing 95% confidence intervals as estimated by the modelers. The solid horizontal line is the observation with the 95% confidence interval indicated by the dashed lines.

33 The main LIETDOS-BIO features As the organism for which DCC calculated is defined by user, there is possibility for optional using references as well as other organisms or criteria. The application of stochastic and probabilistic approach is one of possibility to improve the correctness of biota exposure predictions. Radiation Protection and radiological dose assessment tools are well established for humans through the ICRP and national recommendations. Up to now Environment protection from ionizing radiation in Lithuania is accepted as much as it is interconnected with human exposure. THANK YOU FOR ATTENTION!


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