1. College of Engineering Oregon State University DOE’s Graded Approach for Evaluating Radiation Doses to Biota: Derivation of Screening and Analysis Methodologies covell011.1 MBdocument4/13/981:12 PM KA Higley, Oregon State University ;

2. Oregon State University Nuclear engineering & Radiation Health Physics Overview Technical Marching Orders Goals Limitations Conditions Derivation of Technical Method Assumptions Screening Phase Analysis Phase Product: Electronic Spreadsheets Ongoing Development / Implementation Issues

3. Oregon State University Nuclear engineering & Radiation Health Physics Technical Marching Orders Goal: Simple, defensible, user friendly method Limitations & Conditions: Utilize existing generic & site-specific data Broad-based application (mice to elephants) Provide departure point for in-depth analysis Applicable to multiple media: Soil Sediment Water

4. Oregon State University Nuclear engineering & Radiation Health Physics Biota Dose Evaluation Methodology Technical Approach Basic method & assumptions External dose calculation Internal dose calculation Screening phase (Lumped Parameter) Detailed Analysis (Kinetic/Allometric) Quality Assurance Uncertainty analysis Real-world verification

5. Oregon State University Nuclear engineering & Radiation Health Physics Basic Method Dose: function of contaminant concentration in environment sum of internal & external contributions Evaluate for unit contaminant concentration (e.g., 1 Bq g -1 ) single media (e.g., soil) Ratio calculated dose to standard (e.g., 0.01 Gy d -1 ) Back calculate media limit Use sum of fractions approach for: multiple media multiple nuclides

6. Oregon State University Nuclear engineering & Radiation Health Physics External Dose Calculations Homogeneous nuclide distribution Infinite source Infinitesimal receptor organism Source & receptor geometry: water & soil sediment

7. Oregon State University Nuclear engineering & Radiation Health Physics Internal Dose Assumptions Organism is a “blob” of tissue All decay energies retained in tissue (i.e., infinite receptor) Alpha dose-modifying factors (i.e., w R = 20) * Chain-decay progeny included (E.F. = 1)* Nuclides homogeneously distributed * user can modify

8. Oregon State University Nuclear engineering & Radiation Health Physics Screening Phase Calculations Predictive (empirical) parameters Ratios concentration in organism to surrounding media CR B iv Literature values available Many nuclides Plant to soil Aquatic species to water Allows back-calculation of media concentration corresponding to limiting internal dose

9. Oregon State University Nuclear engineering & Radiation Health Physics Selecting Target Organisms Dose standard aquatic animals terrestrial plants terrestrial animals Anything left out?

10. Oregon State University Nuclear engineering & Radiation Health Physics Screening Method Example - Plant Utilizes lumped parameter, B iv Derives limiting soil value Allows modification of screening limit where data on B iv available

11. Oregon State University Nuclear engineering & Radiation Health Physics Site Specific Screen (Fail Initial Screen) Step 1 lumped parameters too restrictive Examine and modify B iv s using general literature Step 2 No literature values available or no benefit Begin more detailed analysis Step 3 Secondary method Choose kinetic/allometric approach Consider site-specific parameters Re-visit estimate of internal tissue concentration Account for finite contamination Point of departure - lumped parameter values

12. Oregon State University Nuclear engineering & Radiation Health Physics Analysis Phase: Areas of Modification inhalationingestion external Internal pathways are reexamined first

13. Oregon State University Nuclear engineering & Radiation Health Physics Kinetic Approach, Internal Exposure Input RateLoss Rate Body Burden

14. Oregon State University Nuclear engineering & Radiation Health Physics Body Burden Estimates time q Function of: Body mass Intake rate Loss rate Exposure time Need to address: varying mass intake exposure period

15. Oregon State University Nuclear engineering & Radiation Health Physics Useful Relationships Allometric Relationships Y =  X  Cross species relationships Empirically obtained Derived from energy/nutrient transport limitations Mass and Metabolic Rate M 3/4 (Ingestion, Inhalation) M 1/4 (Life-span) aM x (biological elimination rate) Mass and Home Range M ~3/4 (Defining exposure areas)

16. Oregon State University Nuclear engineering & Radiation Health Physics Combining Kinetic & Allometric Methods Allows prediction of body burden for any body mass lifespan loss rate Can be tailored to specific species Stochastic analysis used to ground truth approach and compare to “lumped” parameters

17. Oregon State University Nuclear engineering & Radiation Health Physics Pathways Included in Allometric Method

18. Oregon State University Nuclear engineering & Radiation Health Physics Allometric & Kinetic Approach

19. Oregon State University Nuclear engineering & Radiation Health Physics Method Assessment Graded Approach provides for consistency between screening and analysis phase Allometric predictions compared to real data Uncertainty analysis (90 th percentile?) Sensitivity Analysis Initial results look very promising Additional analysis continuing

20. Oregon State University Nuclear engineering & Radiation Health Physics Input Parameter Values

21. Oregon State University Nuclear engineering & Radiation Health Physics Output Distributions

22. Oregon State University Nuclear engineering & Radiation Health Physics Electronic Spreadsheets Encodes Method Microsoft Excel ® Visual Basic ® Undergoing Review

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29. Oregon State University Nuclear engineering & Radiation Health Physics Riparian worksheet continued

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33. Oregon State University Nuclear engineering & Radiation Health Physics Terrestrial Animals, continued

34. Oregon State University Nuclear engineering & Radiation Health Physics Terrestrial Animals, continued

35. Oregon State University Nuclear engineering & Radiation Health Physics Ongoing Issues Multi-component retention functions Additional Nuclides Technical Accuracy Chain-Decay Nuclides (equilibrium fraction = 1) Internal Dose Factors Radiation weighting factor for  - emitters Adjustment Factors size of contaminated zone & organism home range subsurface contamination

36. Oregon State University Nuclear engineering & Radiation Health Physics Comparisons - Sediment

37. Oregon State University Nuclear engineering & Radiation Health Physics Comparisons - Soil

38. Oregon State University Nuclear engineering & Radiation Health Physics Comparisons - Water

39. Oregon State University Nuclear engineering & Radiation Health Physics Summary & Conclusions Method undergoing QA/QC checks reality check on lumped parameters Additional refinement expected: data printouts more logical progression One-year trial application

40. Oregon State University Nuclear engineering & Radiation Health Physics For further information Contact (in lieu of S. Domotor) Kathryn Higley higley@ne.orst.edu 541-737- 0675 Department of Nuclear Engineering Oregon State University Corvallis OR 97331-5902