Som e Conclusions of the Project BioMoSA for Perform ance Assessm ents of Radioactive W aste Disposal Geert Olyslaegers Research Unit Biosphere Impact Studies Vienna, 16 March 2010 1
What is on the menu ?? • Definition and Objectives of the BioMoSA Project • Application of the BIOMASS Reference Biosphere Approach • A Selection of Some of the Results • Conclusions 2
BioMoSA focused on different problems • 2-year EU 5th framework project (12/ 2001-11/ 2003) • Radioactive waste needs to be isolated from the environment and humans • Regulatory standards o Adequate isolation of radioactive from biosphere and humans o Limitation of possible radiological consequences due to hypothetical releases of radionuclides to the environment • Demonstration of compliance • Biosphere changes with time: Impact of climate 3
In BioMoSA different models were used by different participants • GSF - Germany* o Analytical equations using Excel and Crystal Ball for uncertainty analysis • CIEMAT - Spain o Amber Software (QuantiSci): dynamic compartmental model • SCK• CEN - Belgium o Fortran Software (CVF) (semi-equilibrium model) • University of Veszprem - Hungary o ModelMaker (2000): dynamic compartmental model • Studsvik EcoSafe - Sweden o PRISM Windows 5.0 (Studsvik Eco & Safety AB’s (EcoSafe) tool) 4 * Coordinator
The EU BioMoSA project wanted to give confidence to the public • Objectives: o Development of site-specific biosphere models for 5 sites in Europe using the BIOMASS Reference Biosphere Methodology o Comparison of structure, results and uncertainties o Development of a generic biosphere assessment tool o Compare site-specific and generic models o Identify relevant site-specific and generic features, events and processes 5
The BIOMASS Reference Biosphere Methodology is used Assessm ent Context System identification & justification Review & Biosphere System FEP I teration Description Screening Potentially exposed groups Model Developm ent & Data I m plem entation protocol 6 � I AEA approach
The assessment context can be subdivided in 8 different steps • Assessment purpose • Assessment endpoints • Assessment philosophy • The type of repository system • The site context • Source terms and the geosphere- biosphere interface • Societal assumptions • Time frames 7
The assessment was performed as realistic as possible • Present day conditions o Technology, society, living habits • Radionuclides (incl. daughters) o Cl-36, Se-79, Tc-99, I-129, Cs-135, Ra-226, Pa-231, Np-237, U-238, Pu-239 • Time frame o 90 % of equilibrium in soil achieved • Annual effective doses o infants and adults o Uncertainty of doses 8
5 different sites were considered • Hungary: o Intensive agriculture o Cold winters, hot summers o Pronounced rain deficit during the vegetation period • Spain o Extensive land use o Mild winters, hot and very dry summers • Belgium and Germany o Intensive agriculture o Mild winters, cool summers o Low to moderate precipitation deficit • Sweden o Extensive agriculture o Cold winters and cool summers o Little precipitation deficit 9
Different geosphere biosphere interfaces were considered at different location � • Belgium well, river � • Germany well � • Hungary well, lake � • Spain well, dam, river, � sub-surface soil � • Sweden well, lake � sub-surface soil � • Generic all possible interfaces 10
Within the system identification and justification itself some enquiries are made as well No Biosphere system pre-defined by explicit legislation or guidance ? Yes No Biosphere system change to be considered ? Yes Sequential Select approach to represent biosphere system change Non-sequential 11
The Biosphere System screening is based on expert judgement Assessm ent Context System identification & justification Review & Biosphere System FEP I teration Description Screening Potentially exposed groups Model Developm ent & Data I m plem entation protocol 12
Interrelationships between compartments are visualised thanks to an interaction matrix 1 2 3 4 5 6 7 8 9 10 Irrigation , Irrigation, Intake: 1 Well Irrigation interception, Ingestion interception Watering translocation Water Irrigation , Ingestion Irrigation, Intake: 2 River supply by interception, interception Watering (after filtration) irrigation translocation Underlying 3 Upwelling Soil layers Root uptake Root uptake Resuspension External Soil root (transpiration (transpiration Soil or exhalation 4 Infiltration irradiation and of 3 H, uptake of 3 H, uptake zone intake (+emanation ingestion of 14 CO 2 ) of 14 CO 2 ) of Rn) 5 Weathering Food crops Ingestion 6 Weathering Pasture Intake Animal 7 Animal metabolism Milk / meat / 8 Ingestion eggs Inhalation and 9 Air Dermal Exposure 13 10 Man
A conceptual model is built based on the interaction matrix Filtration I ngestion Drinking water I ngestion Well I ngestion Food crops Resuspension/ Exhalation Air Radioactive Source I rrigation I nhalation and Underlying soil layers Derm al Exposure Soil Aquifer Man External I rradiation Cattle/ Sheep/ Milk Pasture / Goat Fodder River I ngestion Pork Meat I ngestion W atering Chicken Eggs I ngestion Fish I ngestion Pro m em oria Sediment External I rradiation Downstream Lateral displacem ent 14 Sediment
A generic model was developed by NRPB • Development of a generic model o Contains all FEPs o Contains all Geosphere-Biosphere-Interfaces • Comparison against site-specific models • Identification of important pathways • Suggestions for model simplification 15
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Different exposure pathways were modelled • Ingestion o Drinking water for humans o Watering cattle o Irrigation of crops o Fish consumption • Inhalation of contaminated dust/ radon • External exposure o Contaminated arable land o Contaminated river/ sediments 17
Contamination of the soil depends on the irrigation U 8 400 Cl Average irrigation of food crops (l/m²/a) . Concentration in Soil (Bq/kg dry_weight ) . 7 350 Cs I 6 300 Np Pa 5 250 Pu 4 200 Ra Se 3 150 Tc Irrigation 2 100 1 50 • Interplay between � Soil type 0 0 Spain � Infiltration Belgium Germany Sweden Hungary 18 � Irrigation
Deterministic calculations were performed for all sites Spain 1.E-02 Normalised exposure* (mSv/a per Bq/m³) . Belgium Germany Hungary 1.E-03 Sweden 1.E-04 1.E-05 1.E-06 1.E-07 6 9 9 9 5 6 1 8 7 9 3 7 9 2 3 2 3 3 3 3 - - - 1 1 2 2 2 2 2 e c l C - - - - - - - S T I s a a U p u C R P N P 19 * Normalized exposure to adults for the well scenario
‘Local’ aspects are influencing the Dose (mSv/y)/(Bq/m³). Dose (mSv/y)/(Bq/m³). 0.0E+00 0.0E+00 5.0E-04 5.0E-04 1.0E-03 1.0E-03 1.5E-03 1.5E-03 2.0E-03 2.0E-03 2.5E-03 2.5E-03 3.0E-03 3.0E-03 3.5E-03 3.5E-03 4.0E-03 4.0E-03 dose of the daughter 226Ra 226Ra 226 Ra 226 Ra E E 231Pa 231Pa 231 Pa 231 Pa 226Ra 226Ra 226 Ra 226 Ra D D 237Np 237Np 237 Np 237 Np 210Pb 210Pb 210Po 210Po 222Rn 222Rn 226Ra 226Ra Adults Adults 210 Pb 210 Pb 210 Po 210 Po 222 Rn 222 Rn 226 Ra 226 Ra 226Ra 226Ra 226 Ra 226 Ra 20 B B 231Pa 231Pa 231 Pa 231 Pa 226Ra 226Ra 226 Ra 226 Ra 227Ac 227Ac 231Pa 231Pa 233Pa 233Pa 237Np 237Np 231Pa 231Pa 231 Pa 231 Pa H H 227 Ac 227 Ac 231 Pa 231 Pa 233 Pa 233 Pa 237 Np 237 Np 237Np 237Np 237 Np 237 Np 226Ra 226Ra 226 Ra 226 Ra E E 231Pa 231Pa 231 Pa 231 Pa 226Ra 226Ra 226 Ra 226 Ra D D 237Np 237Np 237 Np 237 Np Infants Infants 226Ra 226Ra 226 Ra 226 Ra B B 231Pa 231Pa 231 Pa 231 Pa 226Ra 226Ra 226 Ra 226 Ra 231Pa 231Pa H H 231 Pa 231 Pa 237Np 237Np 237 Np 237 Np
Differences between age groups are mostly limited 1.0E-01 1.0E-01 Total annual dose (mSv/y per Bq/m³) . Total annual dose (mSv/y per Bq/m³) . 1.0E-02 1.0E-02 1.0E-03 1.0E-03 1.0E-04 1.0E-04 1.0E-05 1.0E-05 1.0E-06 1.0E-06 1.0E-07 1.0E-07 36 Cl 36 Cl 99 Tc 99 Tc 129 I 129 I 237 Np 237 Np 238 U 238 U 1.0E-08 1.0E-08 Belgium (adult: � /infant: � ), Germany (adult: � /infant: � ), Hungary (adult: � /infant: � ), Spain (adult: � /infant: � ) and Sweden (adult: � /infant: – ) 21
Sometimes large differences are found between models 1.0E-01 1.0E-01 Total annual dose (mSv/y per Bq/m³) Total annual dose (mSv/y per Bq/m³) . . 1.0E-02 1.0E-02 1.0E-03 1.0E-03 1.0E-04 1.0E-04 1.0E-05 1.0E-05 1.0E-06 1.0E-06 1.0E-07 1.0E-07 79 Se 79 Se 135 Cs 135 Cs 226 Ra 226 Ra 231 Pa 231 Pa 239 Pu 239 Pu 1.0E-08 1.0E-08 Belgium (adult: � /infant: � ), Germany (adult: � /infant: � ), Hungary (adult: � /infant: � ), Spain (adult: � /infant: � ) and Sweden (adult: � /infant: – ) 22
Making a distinction between important and less important pathways is necessary % determ. % determ. results results pathway pathway no no no no > 10 > 10 > 7,5 > 7,5 < 7,5 < 7,5 % % % % % % Σ S doses from S doses from yes yes yes yes pathways omitted pathways omitted from the biosphere from the biosphere � � � � � � model model no no no no > 20 > 20 > 15 > 15 < 15 < 15 % % % % % % yes yes yes yes � 2 � 2 � 2 � 2 � � 23
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