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- Xu, Shulan, et al.
(författare)
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A regulatory modelling strategy for review of dose calculations
- 2008
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Ingår i: Proceedings of The 12th International High-Level Radioactive Waste managemenent Conference. - : American Nuclear Society. - 9780894480621 ; , s. 466-472
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Konferensbidrag (refereegranskat)abstract
- To be able to carry out review functions regulatory authorities must be able to make critical evaluations of proponent's performance assessment (PA) cases. In Sweden the Swedish Radiation Protection Authority (SSI) aims to have in place its own suite of PA tools. These will be used to address the forthcoming PAs submitted by the Swedish Nuclear Waste Management Company (SKB) for a geological repository for spent fuel (2010). This paper looks at the role and application of the regulator's models to important features of current modelling in SKB 's latest PAs. The SSI modelling tools are applied to demonstrate a possible size of the contaminant area due to leakage of radionuclides from a damaged canister. An improved representation of these processes will enhance our understanding of biosphere functions and provide a better basis for evaluating radiological consequences in the safety assessment.
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| 4. |
- Klos, Ryk, et al.
(författare)
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Potential for high transient doses due to accumulation and chemical zonation of long-lived radionuclides across the geosphere-biosphere interface
- 2011
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Ingår i: Radioprotection - Revue de la Societé Francaise de Radioprotection. - : EDP Sciences. - 0033-8451 .- 1769-700X. ; 46:6, s. S453-S459
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Tidskriftsartikel (refereegranskat)abstract
- Planning for the disposal of spent nuclear fuel is at an advanced stage in several nations around the world. Licensing of the disposal facility requires correspondingly detailed assessment of the future performance of the facility. With increased site-specific detail available to the assessment, local characteristics play an increasingly important role in determining the potential radiological risk posed by releases to the biosphere. In this paper we go beyond existing reference biosphere models and investigate the potential for specific accumulation mechanisms. The implications for the modelling carried out in long timescale performance assessment are discussed.
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- Marklund, Lars, et al.
(författare)
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Accumulation in the overburden of radionuclides from a leaking nuclear waste repository
- 2008
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Ingår i: American Nuclear Society - 12th International High-Level Radioactive Waste Management Conference 2008. - 9780894480621 ; , s. 473-478
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Konferensbidrag (refereegranskat)abstract
- The spatial distribution of possible discharge areas of radionuclides originating from repositories of high level radioactive nuclear waste was assessed. This was done by using a 3-D transport model. The results indicate "hot-spots" in the landscape where the radionuclides most likely emerge. These hot-spots are highly related to the hydrological network consisting of streams, lakes and wetlands. The geological factors creating this pattern as well as the characteristics that distinguish these areas from others were investigated. Our result suggests that these hot-spots occur in low elevation areas where the quaternary deposits are significantly greater than the average thickness in the area. The most important factors for the locations of the hot-spots are landscape topography and fracture distribution in the bedrock. As a result of the relationship between, fracture zones, topography and streams, the importance of the topography for the discharge area distribution is not contradicted by the heterogeneity in the bedrock as long as the undulation of the groundwater surface is not extremely small. Due to the similarities within deep groundwater discharge areas, one can make site-specific analyses in one area, which have a broad applicability for migration of radionuclides originating from a nuclear waste repository.
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| 7. |
- McDonnell, J.J., et al.
(författare)
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How old is streamwater? : Open questions in catchment transit time conceptualization, modelling and analysis
- 2010
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Ingår i: Hydrological Processes. - : John Wiley & Sons. - 0885-6087 .- 1099-1085. ; 24:12, s. 1745-1754
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Tidskriftsartikel (refereegranskat)abstract
- The time water spends travelling subsurface through a catchment to the stream network (i.e. the catchment water transit time) fundamentally describes the storage, flow pathway heterogeneity and sources of water in a catchment. The distribution of transit times reflects how catchments retain and release water and solutes that in turn set biogeochemical conditions and affect contamination release or persistence. Thus, quan- tifying the transit time distribution provides an important constraint on biogeochemical processes and catchment sensitivity to anthropogenic inputs, contamination and land-use change. Although the assumptions and limitations of past and present transit time modelling approaches have been recently reviewed (McGuire and McDonnell, 2006), there remain many fundamental research challenges for understanding how transit time can be used to quantify catchment flow processes and aid in the development and testing of rainfall–runoff models. In this Commen- tary study, we summarize what we think are the open research questions in transit time research. These thoughts come from a 3-day workshop in January 2009 at the International Atomic Energy Agency in Vienna. We attempt to lay out a roadmap for this work for the hydrological commu- nity over the next 10 years. We do this by first defining what we mean (qualitatively and quantitatively) by transit time and then organize our vision around needs in transit time theory, needs in field studies of tran- sit time and needs in rainfall – runoff modelling. Our goal in presenting this material is to encourage widespread use of transit time information in process studies to provide new insights to catchment function and to inform the structural development and testing of hydrologic models.
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