Scales for Post-Closure Assessment Scenarios (SPACE)
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BIOPROTA StrålevernRapport 2016:2 Scales for Post-closure Assessment Scenarios (SPACE) Addressing spatial and temporal scales for people and wildlife in long-term safety assessments Reference: Scales for Post-closure Assessment Scenarios (SPACE) - Addressing spatial and temporal scales for people and wildlife in long-term safety assessments StrålevernRapport 2016:2. Norwegian Radiation Protection Authority, 2016. Language: English. Key words: Safety assessment, radionuclides, non-human biota, spatial scale, temporal scale Abstract: This report presents the results of a study called SPACE - Scales for Post-closure Assessment Scenarios to address the issue of averaging scales within long-term non-human biota dose assessments for radioactive waste disposal facilities. Referanse: Scales for Post-closure Assessment Scenarios (SPACE) - Evaluering av skalaer for bruk i langsiktige sikkerhets- vurderinger av miljø inkludert mennesker, dyr og planter. StrålevernRapport 2016:2. Østerås: Østerås: Statens strålevern, 2016. Språk: Norsk. Emneord: Miljøsikkerhetsvurdering, radionuklider, planter, dyr, miljøbeskyttelse Resymé: Rapporten inneholder konklusjoner fra et prosjekt hvor skalaer for mennesker, dyr og planter ble sammenlignet og vurdert for bruk i langsiktige vurderinger av miljøsikkerhet. Head of project: Jelena Mrdakovic Popic Approved: Per Strand, director, Department of Nuclear Safety and Environmental Radioactivity 93 pages. Published 2016-02-19. Cover design: 07 Media. Printed by 07 Media. Printed number: 100 (02-16) Norwegian Radiation Protection Authority, P.O. Box 55, N-1332 Østerås, Norway. Telephone +47 67 16 25 00, fax + 47 67 14 74 07. E-mail: [email protected] www.nrpa.no ISSN 1891-5191 (online) ISSN 0804-4910 (print) BIOPROTA StrålevernRapport 2016:2 Scales for Post-closure Assessment Scenarios (SPACE) Addressing spatial and temporal scales for people and wildlife in long-term safety assessments Statens strålevern Norwegian Radiation Protection Authority Østerås, 2016 Introduction BIOPROTA (www.bioprota.org) is an international collaboration forum, which seeks to address key uncertainties in the assessment of radiation doses in the long term arising from release of radionuclides as a result of radioactive waste management practices. The general objectives of BIOPROTA are to make available the best sources of information to justify modelling assumptions made within radiological assessments of radioactive waste management. Particular emphasis is on key data required for the assessment of long-lived radionuclide in the biosphere, and the associated radiological impact, following discharge to the environment or release from solid waste disposal facilities. Objective and scope of the report In last decade, developments in international environmental protection requirements regarding ionizing radiation have included a significant shift from historically used anthropocentric view to ecocentric view. In that sense, the ICRP specifically included environmental radiological protection objectives in their 2007 recommendations [ICRP, 2007]. These have been interpreted in the context of radiological protection requirements relating to geological disposal facilities for long-lived solid radioactive waste [ICRP, 2012] such that environmental radiological protection is specifically considered as an additional line of argument and reasoning in building a safety case. The inclusion of environmental radiological protection recommendations is intended as a means of broadening the basis for risk-informed decision-making. The IAEA in their International Basic Safety Standards [IAEA, 2014] also refer to environmental protection, acknowledging that: “In a global and long term perspective, protection of people and the environment against radiation risks associated with the operation of facilities and the conduct of activities … is important to achieving equitable and sustainable development” (para 1.32). With respect to this, methodologies to enable assessments of the potential impact of releases of radioactivity to the environment on species of animal and plant, commonly referred to as non-human biota, have been recently developed. This report presents the results of a study called SPACE - Scales for Post-closure Assessment Scenarios, which was organised through the BIOPROTA forum, to address the issue of averaging scales within long- term non-human biota dose assessments for radioactive waste disposal facilities. The main objective has been to improve the understanding of temporal and spatial scales for populations of non-human biota and their commensurability with current approaches to human spatial and temporal averaging, specifically within the context of long-term safety assessments of releases of radionuclides to the biosphere from radioactive waste repositories. The need arises because the averaging based on assessment of human exposure, typically used in past assessments, has been considered as inappropriate in many situations. The rationale behind spatial scales of assessment in long-term safety assessments has been examined, both in terms of dose and risk assessments for people and for non-human biota. Conclusions The report may help in considerations of temporal and spatial scales in future dose assessments for non- human biota populations in relation to release scenarios for radioactive waste disposal facility. A suggested approach for further investigation of spatial and temporal scales of assessment for biota is presented, while its application is demonstrated for a range of radionuclides that are likely to be released from radioactive waste disposal facilities. BIOPROTA Scales for Post - closure Assessment Scenarios (SPACE), August 2015 ii Although the scope of the scales assessment has been limited in this study to biota of temperate terrestrial ecosystem, the general intention has been to apply the conclusions and lessons learned to other assessment types and various ecosystems. Both the regulatory context and the available approaches have been considered and issues associated with the incorporation of biota-specific scales of assessment in long-term safety assessments identified. The international and national guidance increasingly suggest giving the specific consideration of the protection of the environment and biota in safety and risk assessments. There may be merit in giving further consideration to the utilisation of the biosphere by populations of plants and animals that may be exposed due to their possible occupancy in areas potentially affected by discharge zones concurrently to the consideration of human utilisation of the system. Jelena Mrdakovic Popic, NRPA Reference: StrålevernRapport 2015:2 Scales for Post-closure Assessment Scenarios (SPACE) ISSN 1891-5205 (online) ISSN 0804-4910 (print) BIOPROTA Scales for Post - closure Assessment Scenarios (SPACE), August 2015 iii B IOPROTA Key Issues in Biosphere Aspects of Assessment of the Long-term Impact of Contaminant Releases Associated with Radioactive Waste Management Scales for Post-closure Assessment Scenarios (SPACE) Addressing spatial and temporal scales for people and wildlife in long-term safety assessments PREFACE BIOPROTA is an international collaboration forum that seeks to address key uncertainties in the assessment of radiation doses in the long term arising from release of radionuclides as a result of radioactive waste management practices. It is understood that there are radio-ecological and other data and information issues that are common to specific assessments required in many countries. The mutual support within a commonly focused project is intended to make more efficient use of skills and resources, and to provide a transparent and traceable basis for the choices of parameter values, as well as for the wider interpretation of information used in assessments. A list of sponsors of BIOPROTA and other information is available at www.bioprota.org. The general objectives of BIOPROTA are to make available the best sources of information to justify modelling assumptions made within radiological assessments of radioactive waste management. Particular emphasis is to be placed on key data required for the assessment of long-lived radionuclide migration and accumulation in the biosphere, and the associated radiological impact, following discharge to the environment or release from solid waste disposal facilities. The programme of activities is driven by assessment needs identified from previous and on-going assessment projects. Where common needs are identified within different assessment projects in different countries, a common effort can be applied to finding solutions. This report has been prepared as input to a project to investigate the appropriate spatial and temporal scales for various types of plants and animals in long-term safety assessments, in terms of population level impacts, and compared to spatial scales used for human assessments. In this project, the overall objective is to advance the understanding of temporal and spatial scales for wildlife populations and the commensurability of these with current approaches to human spatial and temporal averaging, specifically within the context of long-term safety assessments. The variety of plants and animals in the natural environment is immense and, as such, the scope of the project has necessarily been limited to the general types of plant and animal representative of temperate terrestrial ecosystems being selected as the focus for evaluation. It is intended that the lessons learnt can then