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Regulations the Netherlands for regular discharges of radioactivity ( aquatic environment). R. Heling NRG-Arnhem The Netherlands. Hydrological Models Relevance. Application : Nuclear accidents Regular discharges Relevance :
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Regulations the Netherlandsforregular discharges of radioactivity(aquatic environment) R. Heling NRG-Arnhem The Netherlands EMRAS-II IAEA, Vienna
Hydrological ModelsRelevance • Application: • Nuclearaccidents • Regular discharges • Relevance: • dosisbelasting niet verwaarloosbaar maar niet cruciaal in reguliere situaties, in ongevalssituaties perceptie van het risico een probleem EMRAS-II IAEA, Vienna
Type of modelling • Runoff, Transport land-to-water • Transport in rivers • Transport in estuaries en coastalregions • Transport in reservoirs en lakes • Transport in groundwater EMRAS-II IAEA, Vienna
Different kind of models (1) • Hydrodynamics • Transport of radionuclides • Near- field to far – field modelling • Modelling of short, middle, and long-term EMRAS-II IAEA, Vienna
Aquatic model and type (2) • Runoff: 2D (grens: 1000 km2) algoritme • Rivers: 2D, 1D, box, multi-box • Lakes: 3D, 2D, box • Estuaries: 3D, 2D, box • Coast: Box, 2D, 3D • Groundwater: 1D, 2D, 3D EMRAS-II IAEA, Vienna
Modelberekeningen • Oplossen van de advectie/diffusie vergelijking (numeriek) • Verzamelen inputgegevens • bijv: meteo, bathymetry, lozingen, water afvoer, salinity, getijdengegevens • Klant krijgt eindresultaat toegesneden op de vraagstelling EMRAS-II IAEA, Vienna
Tsjernobyl koelvijver + Dnjepr EMRAS-II IAEA, Vienna
3D model Estuarium (Dniepr Boeg) Sr-90 EMRAS-II IAEA, Vienna
Groundwater model (beneath the Chernobyl) Sr-90 90Sr (Bq/L) in groundwater - 2045 EMRAS-II IAEA, Vienna
North Sea – THREETOX Cs-137 in Seawater Cs-137 Bottom sediments Hypothetical Discharge Borssele PP (NL) EMRAS-II IAEA, Vienna
POSEIDON – Coastal regions Local compartments can be added by user EMRAS-II IAEA, Vienna
BesluitStralingsbescherming2001 Article 35 (and 108) EMRAS-II IAEA, Vienna
Necessary to model or not? • “Radiotoxicity-equivalence • Activityleading to 1Sv effectivedosebyingestion • Modelling not needed if: • Surface waters: A= 0.1 RE • On the sewer system: A = 10 RE EMRAS-II IAEA, Vienna
Derived criteria Wsn – secondary level test – assuming dilution 108, leading to 1 uSv/ yr, (unit f RE) so Wsn = 100 RE, leading to this dose. Wmax = A/RE Criteria (max) - 100 uS / yr (max per location, above no permit) Criteria : (low) 1 uS / yr (SN secondary level) – under this no modelling needed External irradiation: 10 us/yr (SN), under this no modelling needed Wmax/Wsn <1; dose < 1 uSv, no modelling needed EMRAS-II IAEA, Vienna
Discharge per year, under which no permit needed, otherwise acquiring permit obliged (dose less than 10 uSv/yr). EMRAS-II IAEA, Vienna
To model objects: Rivers Lakes Coastalregion Estuaries Waste Water TreatmentInstallations Important Note: IF the system is connected to the coastalregion, the these shouldbeincluded as well Model Concept “DOVIS”Dosisberekening voor de Omgeving bij Vergunningverlening Ioniserende Straling EMRAS-II IAEA, Vienna
Processes sedimentation resuspension Transport betweencompartments Daughter - nuclides Standard Kd- values Notobliged: Sediment - water interaction These processes have to taken account in the model, more processes are of courseallowed in more complex models Model concept“DOVIS” EMRAS-II IAEA, Vienna
Exposurepathways Consumptionfisheryproducts Consumptiondrinking water Consumptionagriculturalproducts (irrigation) Externalirradiation Secondary pathways Usage of harboursludge and sewersludge in agriculture Irrigation Effect of flooding Residence at the coast (sea) Model concept “DOVIS” EMRAS-II IAEA, Vienna
Source to Dose Sewage sludge Floodplains Meat/Dairy products Water Fish Dose Calculations (input: consumption Behaviour Population) Drinking water Sediment Irrigation Agricultural Pr. Sand External Irridation + (Inhalation) EMRAS-II IAEA, Vienna
Gridresolution (homogeneousmixing) DynamicorSteady-State Conservativeornon-conservativebehaviourradionuclide Reference Group (>5% of the population) Available input data (veryrestrictive) Drinking water inletlocation (lakes, rivers) Fish migration ChoiceDispersion model“Criteria” EMRAS-II IAEA, Vienna
Company: Discharge data Discharge scenario Discharge rates Radionuclides in discharge Consultant: Collects model input Calculationconcentrationsradionuclides Calculation doses Company & Consultant EMRAS-II IAEA, Vienna
Case Study (1): North Sea • Discharges NORM on the continental shelf (continuous) • Discharges of radioactivity in the Westerscheldt estuary. (semi-continuous) • Question: Does it matter which compartments are chosen, and which model has been applied EMRAS-II IAEA, Vienna
Scenario 1: Coast at Rotterdam (min) Scenario 2: Coast at Rotterdam (max) Scenario 3: ContinentalShelf Scenario 4: Westerschelde estuary Comparison between NRG models for the coastal waters with PC CREAM (commercial dose assessment tool, HPA (formerly NRPB, UK) Case Study (2): Noordzee EMRAS-II IAEA, Vienna
Case Study (3): NorthSea Model configurationPC CREAM - NRG models Model configurations EMRAS-II IAEA, Vienna
NRG – model 10 compartiments EMRAS-II IAEA, Vienna
Exposurepathways inhalation (particles, sea spray) consumption (fish, mussels, shrimps) Externalirradiation (beach) Dose After a year (Scen. 4. Westerscheldt) YearlyDose (other scenario's) Discharge scenario 4: realestimated release into the environment Other scenario's: Unit Discharge Case Study (4): Noordzee Model input EMRAS-II IAEA, Vienna
Case Study (5): NoordzeeReferentiegroepen EMRAS-II IAEA, Vienna
Case Study (6) NoordzeeTabel: resultaat NRG-1 model 10 compartimenten: Rotterdam-Den Helder 1GBq/yr EMRAS-II IAEA, Vienna
Case Study (7): Noordzee Resultatenvergelijking PC-CREAM en NRG modellen (-) Dominant belastingspad 1 TBq /jaar Ra-226 (2.8 105 RE) EMRAS-II IAEA, Vienna
Discharge Westerscheldt (1E+5 MBq/y) EMRAS-II IAEA, Vienna
Case Study (8): NorthSeaConclusies • Choice of compartment size affects the results. • Commercial software not straight-forwarded applicable (be careful for wrong usage). • Inhalation negligible exposure pathway • Dosis below the legal upper limit of 100 Sv EMRAS-II IAEA, Vienna
Huidige Beschikbaarheid Modellen NRG • Alle lozingssituaties zijn te modelleren m.b.v RIVTOX, COASTOX, SUSTOX, WATOX, THREETOX, LAKECO-B, en POSEIDON • Meestal voldoet 1D model of compartiment model voor reguliere lozing • Aanpassing voor RWZI’s en baggerslib noodzakelijk EMRAS-II IAEA, Vienna
Tot slot: Praktische punten • Binnen NRG expertise aanwezig • Projecten kunnen worden geformuleerd • Voor toxische stoffen expertise binnen KEMA/NRG • Alle modellen betrouwbaar: uitgebreid getest en gevalideerd in internationale projecten (EC, IAEA) in de afgelopen 15 jaar EMRAS-II IAEA, Vienna