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Centre for Ecology & Hydrology – Lancaster 1 st – 3 rd April 2014
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Give an overview of what may impact on assessment results using the available approaches In part based on things we know are being done Consider chronology of development, misuse of default values, double accounting, screening tier application Not considering dispersion modelling and sampling strategies www.radioecology-exchange.org
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Environmental Radiological assessment approaches have developed rapidly over the last 15 y A number of approaches have been made freely available Some of these have been superseded But they are still available & are being used www.radioecology-exchange.org
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UK Environment Agency R&D128 - 2001 Spreadsheet model for limited number of radionuclides Comparatively limited review to derive CR values Dosimetry methods similar to later approaches Environment Agency Sp1a – 2003 Supports R&D128 including derivation of complete CR data sets using a ‘guidance approach’ (can be extremely conservative) www.radioecology-exchange.org
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Europe FASSET (EC) 2001-2004 Establish a framework for radiological environmental protection from source characterisation – interpretation, including: Tabulated CR and DCC values for: radionuclides of 20 elements circa 30 reference organism in 7 ecosystems Developed the on-line FASSET Radiation Effects Database www.radioecology-exchange.org
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Europe EPIC (EC) 2000-2003 Establish a framework for radiological environmental protection for the Arctic Ran concurrent to FASSET and shared CR database Although presented differently and for only 12 radionuclides DCCs derived by a different method Allowed participation of Russian institutes leading to EPIC effects database www.radioecology-exchange.org
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Europe ERICA (EC) 2004-2007 Developed the CR and effects (FREDERICA) databases from FASSET & EPIC Developed FASSET dosimetry methodology Adapted ‘guidance’ for selecting missing CRs from EA SP1a Output - the ERICA Tool implementing the ERICA Integrated Approach More generic ecosystem types (because of lack of data) than FASSET and adapted reference organism list (to encapsulate European protect species & remove some unjustified sub-categories) Derived 10 µGy/h screening dose rate (by SSD) Being maintained and updated www.radioecology-exchange.org
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Europe ERICA (EC) 2004-2007 Developed the CR and effects (FREDERICA) databases from FASSET & EPIC Developed FASSET dosimetry methodology Adapted ‘guidance’ for selecting missing CRs from EA SP1a Output - the ERICA Tool implementing the ERICA integrated approach More generic ecosystem types (because of lack of data) than FASSET and adapted reference organism list (to encapsulate European protect species & remove some unjustified sub-categories) Being maintained and updated www.radioecology-exchange.org ERICA supersedes both FASSET and EPIC outputs & EA state intention to move to ERICA (parameters) EC PROTECT supported the 10µGy/h screening dose rate – using additional data and improved data selection
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International IAEA (2009-) Wildlife transfer parameter handbook (in-press) 2013 - initiate group to draft Volume III of ‘Generic models for use in assessing the impact of discharges of radioactive substances to the environment’ Volume III considers wildlife. ICRP Committee 5 (2005-) Provided tabulated DCC values (using ERICA methodology) and summarised effects information (ICRP-108) Report presenting CR values for RAPs (ICRP-114) www.radioecology-exchange.org
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USA USDOE Graded Approach (2002) Initially supported by BCG-Calculator spreadsheet model. Still available – but replaced by: RESRAD-BIOTA Limited and conservative CR values for generic organisms RESRAD-BIOTA v1.5 (2009) includes values from the ERICA (original) CR database in supporting documentation for application in uncertainty analysis www.ceh.ac.uk/PROTECT
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Use out of date approaches unless you can justify why they have been used, e.g.: OK to use R&D128 for noble gases Not OK to use FASSET CR values because they offer more ‘refined’ reference organism list/ecosystem range.... but do be aware that this is an evolving area www.radioecology-exchange.org
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To serve the purpose for which they were intended RESRAD-BIOTA, R&D128(SP1a) and the ERICA Tool give a complete list of radionuclide-organism transfer parameters. ERICA Tool and R&D128 missing values derived using ‘guidance’ approaches. These should not be blindly used in higher tier assessments nor should they be picked out for use in other models/recommendations without being clearly identified as such RESRAD-BIOTA Biv (=CR) values very generic and conservative www.radioecology-exchange.org
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ERICA and R&D128 both clearly identify values which have been derived via guidance approach rather than data But have been taken as ‘values’ www.radioecology-exchange.org
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Some scope for ‘double accounting’ associated with daughter product half-life cut-offs e.g. R&D128 includes all 234 Th and 234 U in DCCs for 238 U Entering both 234 Th and 238 U activity concentrations would over estimate dose rates RESRAD-BIOTA and ERICA both offer the user the opportunity to do similar www.ceh.ac.uk/PROTECT
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Some scope for ‘double accounting’ associated with daughter product half-life cut-offs e.g. R&D128 includes all 234 Th and 234 U in DCCs for 238 U Entering both 234 Th and 238 U activity concentrations would over estimate dose rates RESRAD-BIOTA and ERICA both offer the user the opportunity to do similar www.ceh.ac.uk/PROTECT Understand what daughters are/are not included in default DCCs especially important for assessments of natural radionuclides
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Do not use/accept out of date approaches – unless justified Be aware of potential changes as a consequence of recent transfer parameter reviews & forthcoming ERICA update Ensure no misuse of default values provided by various approaches Use alternatives where justified There are differences between approaches Dosimetric methods tend to give similar results Transfer parameters can add significant variation Screening tiers (see http://dx.doi.org/10.1088/0952- 4746/30/2/S04)http://dx.doi.org/10.1088/0952- 4746/30/2/S04 www.radioecology-exchange.org
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