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Slide 1 PROTECT Workshop, Jan 08. Demonstration Assessment of Doses to Non-human Biota from Olkiluoto Repository and General Considerations for Waste.

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Presentation on theme: "Slide 1 PROTECT Workshop, Jan 08. Demonstration Assessment of Doses to Non-human Biota from Olkiluoto Repository and General Considerations for Waste."— Presentation transcript:

1 Slide 1 PROTECT Workshop, Jan 08

2 Demonstration Assessment of Doses to Non-human Biota from Olkiluoto Repository and General Considerations for Waste Repository Assessments K.L. Smith & C.A. Robinson Enviros Consulting Ltd & A.T.K. Ikonen, Posiva Oy

3 Slide 3 PROTECT Workshop, Jan 08 Overview of presentation  General features of waste repository assessments  Demonstration assessment process for Olkiluoto repository (for Posiva Oy)  BIOPROTA Forum, January 07  Future – current BIOPROTA plans

4 Slide 4 PROTECT Workshop, Jan 08 Repository assessments: what makes them different?  Sub-surface source Relative importance of different ecosystems and organisms Significance of pathways of exposure  Timescales Releases may be extended – may affect different generations Evolution and climate change  Radionuclides Long-lived Key nuclides identified by BIOPROTA: Cl-36, Se-79, Tc-99, I- 129, Pb-210, Po-210, Ra-226, Th-230, Np-237, and U-238

5 Slide 5 PROTECT Workshop, Jan 08 Assessment process  Problem formulation or setting the scope Generic or specific (conservatism or realism) Regulatory or research  Developing an approach Information and methods available Proportionality  A test case…

6 Slide 6 PROTECT Workshop, Jan 08 Demonstration assessment for the waste repository at Olkiluoto  Decision in principle in favour of geological repository at Olkiluoto, southwest Finland  Disposal due to commence in 2020  Regulated by the Radiation and Nuclear Safety Authority (STUK)  Posiva Oy responsible for development of repository  Broad safety case assessment (SCA) being developed

7 Slide 7 PROTECT Workshop, Jan 08 Plan of ONKALO and repository Acknowledgement: plan from Posiva Oy website

8 Slide 8 PROTECT Workshop, Jan 08 Start of work September 2004 Drilling grout holes ONKALO construction and investigations Acknowledgement: photos from Posiva Oy website:

9 Slide 9 PROTECT Workshop, Jan 08 Demonstration assessment process for the Olkiluoto repository  Study objectives Regulatory requirement Choice of methodology  Test Case Assessment Selection of assessment ecosystems and biota Features of test case scenario Methodology applied  Indicative results Acknowledgement: photo from Posiva Oy website

10 Slide 10 PROTECT Workshop, Jan 08 Regulatory Requirement ‘exposures shall remain clearly below the levels which, on the basis of the best available scientific knowledge, would cause decline in biodiversity or other significant detriment to any living population. Moreover, rare animals and plants as well as domestic animals shall not be exposed detrimentally as individuals’ (STUK, 2001, Document YVL 8.4)

11 Slide 11 PROTECT Workshop, Jan 08 Regulatory Requirements  SCA therefore required to demonstrate (in addition to human protection criteria): No decline in biodiversity of current living populations No significant detriment to populations of fauna and flora No detrimental effects on individuals of domestic animals and rare animals and plants  Some assessment assumptions defined: Present kind of living populations; Period of ‘several thousand years’

12 Slide 12 PROTECT Workshop, Jan 08 Choice of Assessment Methodology  Review of available and developing methodologies and applicability to the Olkiluoto site  Methods primarily based on a ‘reference organism’ approach and organisms representative of the local ecosystem  EPIC and FASSET/ERICA most comprehensive methodologies available EPIC - arctic ecosystem likely to more closely represent local conditions (though data gaps remain); FASSET/ERICA – provided data for a range of European ecosystems & wide range of reference organisms (tool not available at time of assessment).

13 Slide 13 PROTECT Workshop, Jan 08 Environment around Olkiluoto  Island to southwest of Finnish mainland  Typical habitats (interwoven) Shallow bays Forests Nutrient rich mires Meadows  Sub-arctic climate  Under-going post-glacial land uplift WetlandsForest/agricultureMarine/coastal areas

14 Slide 14 PROTECT Workshop, Jan 08 Landscape predictions 5850 years AP Reference ecosystems selected for test case Marine/coastal Freshwater Wetland Agriculture/grassland Forest

15 Slide 15 PROTECT Workshop, Jan 08 Identification of relevant biota  STUK requirement Present kinds of living populations Individuals of rare/sensitive species Domestic animals  Generic organisms Simple food webs  Interest species Natura 2000 site descriptions Agricultural statistics Game statistics Local knowledge – species of public interest Interest species

16 Slide 16 PROTECT Workshop, Jan 08 Identification of relevant biota (2)  Sub-set of organisms selected and assigned to ecosystems Occupancy within ecosystem compartments likely to result in increased dose Demonstration of individual endpoints compared to population; Migration between ecosystems (e.g. moose)  Organisms assigned, on basis of general biota characteristics: Concentration ratios Ellipsoid geometries (and associated dose conversion factors) Occupancy factors (on or within soil, sediment & water) – taking account of climate Migratory occupancy (between ecosystems)

17 Slide 17 PROTECT Workshop, Jan 08 Test case organisms – Forest GenericInterest species Grass / herb Shrub Tree Worm Burrowing herbivorous mammal Large herbivorous mammal Average CR values & general habit data Wolf Bear Moose European Hare Rare/sensitive Plant Maximal CR values & habit data

18 Slide 18 PROTECT Workshop, Jan 08 Migratory Interest creatures and occupancy assumptions Interest / Reference CreatureMarineFreshwaterWetland Agriculture/ GrasslandForest Wolf 0.20.8 Bear 0.10.9 Moose Otter 0.5 Goose0.5 European hare 0.5 Salmon0.5

19 Slide 19 PROTECT Workshop, Jan 08 Test case  PANDORA was used to (by Facilia) provide activity concentrations in water, soil and sediment as a function of time within defined biosphere compartments;  Scenario based on assumed source term locations normalised to total 1 Bq/y for each of the following radionuclides into the overall landscape: Cl-36, Ni-59, Se-79, Tc-99, I-129, Cs-135, Po-210, Pb-210, Ra-226, Pu- 239, U-234, U-238, Np-237.  The highest activity concentrations occurring at 10,000 years in each ecosystem type were identified for 1 Bq/y case;  Source term information for 10,000 years for full canister disintegration;  The maximum source term values (in 1 million years) also used for scoping.

20 Slide 20 PROTECT Workshop, Jan 08 Freshwater - disappearing canister scenario

21 Slide 21 PROTECT Workshop, Jan 08 Forest - disappearing canister scenario

22 Slide 22 PROTECT Workshop, Jan 08 Maximum exposed creatures and principal dose contributors EcosystemReference creature Interest speciesPrincipal Radionuclide(s) MarinePhytoplanktonSalmonPu-239 FreshwaterVascular plantFreshwater pearl mussel Pu-239 WetlandBird eggPlantCl-36 Agriculture / grassland Bird eggPlantPu-239, Cl-36, I-129 ForestWormPlantPu-239

23 Slide 23 PROTECT Workshop, Jan 08 Highest dose under worst-case assumptions EcosystemCreature Dose rate (µGy/h) MarineOtter7.65E-09 FreshwaterVascular plant7.32E-09 WetlandBird egg8.98E-11 Agriculture / Grassland Sensitive plant2.33E-07 ForestSensitive plant3.32E-04 Even under maximising assumptions, doses do not approach those likely to cause harm to individuals or populations

24 Slide 24 PROTECT Workshop, Jan 08 General methodological issues  Single stressor assessment (ionising radiation); Chemical toxicity of radionuclides and of non-radioactive releases;  Assessment of population and community effects; Population dynamics; Interdependency of different organisms.  Dose rate benchmarks and effects analysis; Limited data available for key creatures (e.g. for large mammals);

25 Slide 25 PROTECT Workshop, Jan 08 General dose assessment issues  Generic equilibrium concentration ratios and distribution coefficients; Limited database for some organisms and radionuclides; Examples include large mammals (…) Generic assumptions not necessarily applicable to all environments/organisms;  Dose conversion coefficients Mammals  Dose rate weighting factors to allow for RBE of different radiation types

26 Slide 26 PROTECT Workshop, Jan 08 Specific issues for long-term releases of long-lived radionuclides  Treatment of climate and landscape change;  Long-lived nuclide-specific data availability  Dealing with uncertainties, probabilistic assessment and communication;

27 Slide 27 PROTECT Workshop, Jan 08 BIOPROTA  A forum to address uncertainties in the assessment of the radiological impact of releases of long lived radionuclides in to the biosphere (from solid waste disposal facilities)  Commonly focused projects: efficient use of skills and resources transparent and traceable basis for parameter value choice and wider interpretation of assessment information  Participants: National authorities and agencies with responsibility for achieving safe and acceptable radioactive waste management, both regulators and operators Enviros

28 Slide 28 PROTECT Workshop, Jan 08 ‘PROBIOTA’ Forum, January 2007  Forum for the exchange information on the suitability of the current guidance and methods for non-human biota assessments to long-term assessments  Attended by 15 participants from 6 countries (operators and technical support organisations) Hosted by Posiva Oy, in Lappeenranta Finland

29 Slide 29 PROTECT Workshop, Jan 08 ‘PROBIOTA’ Forum identified issues  Applicability of concentration ratios for assessing impacts to NHB  Dealing with site evolution over the timescales required for waste repository PAs and the effect on ecosystems  The value of sensitivity analysis to focus efforts  Dealing with synergistic interactions  Regulatory drivers (focus on present day knowledge and the applicability of this to future scenarios is not clear)  Communicating the results of NHB assessments  Value of follow-on workshops

30 Slide 30 PROTECT Workshop, Jan 08 BIOPROTA - Proposal for sensitivity analysis  Evaluate the robustness of assessment data in relation to the key long-lived radionuclides applicable to deep geological disposal facilities;  Identify important data gaps and uncertainties related to biota dose assessment upon which future tasks may be identified;  Determine the impact of given release scenario assumptions and climate variations on calculated dose rate;  Evaluate the potential range of parameter values used in the assessment, the availability and ‘robustness’ of data;  Undertake a sensitivity analysis to identify the parameters and uncertainties that contribute most significantly to the overall results;  Perform a knowledge quality assessment to identify key gaps in data and understanding;

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