The Experts below are selected from a list of 252 Experts worldwide ranked by ideXlab platform
T.t. Vandergraaf - One of the best experts on this subject based on the ideXlab platform.
-
Radionuclide Migration IN TUFF UNDER UNSATURATED CONDITIONS
2000Co-Authors: T.t. VandergraafAbstract:An understanding of the transport of Radionuclides through unsaturated and saturated tuffaceous material is essential in assessing the safety of the proposed high-level waste repository at Yucca Mountain. Migration experiments with conservative and chemically reactive non-radioactive tracers have been performed at the Busted Butte Unsaturated Zone underground facility, SE of Yucca Mountain, and with Radionuclides in columns of crushed tuff at the Los Alamos National Laboratory. In this paper, complementary Radionuclide Migration experiments, performed under unsaturated conditions in a small block of tuff excavated from Busted Butte, are described.
-
Radionuclide Migration experiments in a natural fracture in a quarried block of granite
Journal of Contaminant Hydrology, 1996Co-Authors: T.t. Vandergraaf, D. J. Drew, Sumio MasudaAbstract:A Radionuclide Migration experiment was performed over a distance of 1 m in a natural fracture in a quarried block of granite. The fracture in the block was characterized hydraulically by measuring the pressure drop in borehole-to-borehole pump tests. The effective fracture volume in the block was ∼100 mL. A silicone coating was applied to the exterior, and the block was immersed in a tank of water to which hydrazine was added to provide a chemically reducing barrier. Migration experiments were performed at a flow rate of 2.2 mL h -1 using 85 Sr, 131 I, 137 Cs, 144 Ce, 152 Eu, 237 Np and 238 Pu. A total of 9.5 L of groundwater was pumped through the fracture, corresponding to ∼95 fracture volumes. Only 85 Sr, 131 I, 137 Cs, 237 Np and 238 Pu were observed in the eluent. Scanning of the fracture surface at the end of the Migration experiment showed limited mobility of α-emitting Radionuclides and of the rare-earth elements, consistent with static sorption data obtained on representative fracture surface material. The mobility of 137 Cs was higher than that of the rare-earth elements, but it was lower than that of 85 Sr. When samples of fracture-coating material were separated into fractions with different specific gravity, there was a clear indication of Radionuclide association with mineral groups.
-
Radionuclide Migration experiments under laboratory conditions
Geophysical Research Letters, 1995Co-Authors: T.t. VandergraafAbstract:Arguments are given in favour of performing non-conservative Radionuclide Migration experiments in natural and artificial fractures under laboratory conditions. Results are presented from a series of Migration experiments performed in a natural fracture in a quarried block of granite with overall dimensions of 81 × 90 × 75 cm. These experiments were conducted in a dedicated experimental facility and were designed to complement field Migration experiments, to develop and test methodologies and to evaluate transport models. The flow path in the fracture was selected from the hydraulic characterization of the fracture using borehole to borehole pumping tests. Following Migration experiments with stable, conservative tracers Br− and uranine, Migration experiments were performed with a number of Radionuclides at a flow rate of 3 mL/h. At the completion of the Migration experiments, the fracture surfaces were scanned using a Ge(Li) gamma detector and an alpha probe to determine the sorbed radioisotope distributions on the fracture surfaces. The results from these experiments show that the behaviour of radioisotopes is usually more complex than can be represented by a simple, reversible sorption coefficient (Ka). However, the transport models that use this simple Ka tend to give conservative estimates of contaminant transport in environmental and safety assessment calculations.
D. Bugai - One of the best experts on this subject based on the ideXlab platform.
-
Radionuclide Migration at experimental polygon at Red Forest waste site in Chernobyl zone. Part 2 Hydrogeological characterization and groundwater transport modeling
Applied Geochemistry, 2012Co-Authors: D. Bugai, N. Van Meir, A. Skalskyy, S. Dzhepo, Y. Kubko, V. Kashparov, D. Stammose, C. Simonucci, A. Martin-garinAbstract:This article represents the second of two articles, which review the main results of the international radioecological projects Chernobyl Pilot Site Project (1999-2003) and Experimental Platform in Chernobyl (2004-2008). These projects studied Radionuclide Migration from the near-surface radioactive waste trench at the Red Forest waste dump in the Chernobyl zone, which contained nuclear fuel particles. This article presents results from the comprehensive hydrogeological site characterization program including the following issues geological structure of the study site, hydraulic properties of the deposits, tracer tests in the aquifer, results of groundwater monitoring and unsaturated zone regime studies, as well as data on the 90Sr distribution in the unsaturated zone and aquifer, and analyses of 90Sr sorption behavior. The derived parameters were used to develop and calibrate 1D (flow tube) and 2D (cross-section) models describing the Migration of 90Sr from the studied waste trench to the unsaturated zone and aquifer over a 16-a period (1986-2002). The models involved the following sub-models (1) the geostatistical (structural) model for radioactivity distribution in the trench (using GSLIB); and (2) the Radionuclide source term model (STERM1D) describing dissolution of fuel particles and a 1D of Radionuclide redistribution in the trench body and unsaturated zone. The MODFLOW - MT3D codes were used to model the 2D 90Sr transport in the aquifer cross-section. Calibration of the 1D model with respect to K ds and dispersivities allowed quite accurate reproduction of 90Sr Migration behavior for the early period (1995-1998). The less perfect fit between the 1D and 2D modeling results and monitoring data for the later period (1999-2002) suggests the need to improve the conceptual Radionuclide Migration model (i.e. to account for transient hydraulic and geochemical regimes of the waste site). © 2011 Elsevier Ltd.
-
Radionuclide Migration at experimental polygon at red forest waste site in chernobyl zone part 2 hydrogeological characterization and groundwater transport modeling
Applied Geochemistry, 2012Co-Authors: D. Bugai, N. Van Meir, Caroline Simonucci, S.p. Dzhepo, A. Skalskyy, Y. Kubko, V. Kashparov, D. Stammose, A MartingarinAbstract:Abstract This article represents the second of two articles, which review the main results of the international radioecological projects: Chernobyl Pilot Site Project (1999–2003) and Experimental Platform in Chernobyl (2004–2008). These projects studied Radionuclide Migration from the near-surface radioactive waste trench at the Red Forest waste dump in the Chernobyl zone, which contained nuclear fuel particles. This article presents results from the comprehensive hydrogeological site characterization program including the following issues: geological structure of the study site, hydraulic properties of the deposits, tracer tests in the aquifer, results of groundwater monitoring and unsaturated zone regime studies, as well as data on the 90Sr distribution in the unsaturated zone and aquifer, and analyses of 90Sr sorption behavior. The derived parameters were used to develop and calibrate 1D (flow tube) and 2D (cross-section) models describing the Migration of 90Sr from the studied waste trench to the unsaturated zone and aquifer over a 16-a period (1986–2002). The models involved the following sub-models: (1) the geostatistical (structural) model for radioactivity distribution in the trench (using GSLIB); and (2) the Radionuclide source term model (STERM1D) describing dissolution of fuel particles and a 1D of Radionuclide redistribution in the trench body and unsaturated zone. The MODFLOW – MT3D codes were used to model the 2D 90Sr transport in the aquifer cross-section. Calibration of the 1D model with respect to Kds and dispersivities allowed quite accurate reproduction of 90Sr Migration behavior for the early period (1995–1998). The less perfect fit between the 1D and 2D modeling results and monitoring data for the later period (1999–2002) suggests the need to improve the conceptual Radionuclide Migration model (i.e. to account for transient hydraulic and geochemical regimes of the waste site).
A. Martin-garin - One of the best experts on this subject based on the ideXlab platform.
-
Radionuclide Migration at experimental polygon at Red Forest waste site in Chernobyl zone. Part 2 Hydrogeological characterization and groundwater transport modeling
Applied Geochemistry, 2012Co-Authors: D. Bugai, N. Van Meir, A. Skalskyy, S. Dzhepo, Y. Kubko, V. Kashparov, D. Stammose, C. Simonucci, A. Martin-garinAbstract:This article represents the second of two articles, which review the main results of the international radioecological projects Chernobyl Pilot Site Project (1999-2003) and Experimental Platform in Chernobyl (2004-2008). These projects studied Radionuclide Migration from the near-surface radioactive waste trench at the Red Forest waste dump in the Chernobyl zone, which contained nuclear fuel particles. This article presents results from the comprehensive hydrogeological site characterization program including the following issues geological structure of the study site, hydraulic properties of the deposits, tracer tests in the aquifer, results of groundwater monitoring and unsaturated zone regime studies, as well as data on the 90Sr distribution in the unsaturated zone and aquifer, and analyses of 90Sr sorption behavior. The derived parameters were used to develop and calibrate 1D (flow tube) and 2D (cross-section) models describing the Migration of 90Sr from the studied waste trench to the unsaturated zone and aquifer over a 16-a period (1986-2002). The models involved the following sub-models (1) the geostatistical (structural) model for radioactivity distribution in the trench (using GSLIB); and (2) the Radionuclide source term model (STERM1D) describing dissolution of fuel particles and a 1D of Radionuclide redistribution in the trench body and unsaturated zone. The MODFLOW - MT3D codes were used to model the 2D 90Sr transport in the aquifer cross-section. Calibration of the 1D model with respect to K ds and dispersivities allowed quite accurate reproduction of 90Sr Migration behavior for the early period (1995-1998). The less perfect fit between the 1D and 2D modeling results and monitoring data for the later period (1999-2002) suggests the need to improve the conceptual Radionuclide Migration model (i.e. to account for transient hydraulic and geochemical regimes of the waste site). © 2011 Elsevier Ltd.
-
Quantitative assessment of Radionuclide Migration from near-surface radioactive waste burial sites: the waste dumps in the Chernobyl exclusion zone as an example
Radionuclide Behaviour in the Natural Environment, 2012Co-Authors: A. Martin-garin, N. Van Meir, Caroline Simonucci, Valery Kashparov, C. Poinssot, H. GeckeisAbstract:Abstract: This chapter aims to describe the lessons learned from the studies of Radionuclide behaviour in the vicinity of the Chernobyl Nuclear Power Plant, as an example of Radionuclide Migration in a contaminated surface site. Between 1999 and 2008, we improved our understanding of the hydrogeological, geochemical and biotic processes that govern in situ Radionuclide Migration in the Red Forest waste dumps of the Chernobyl exclusion zone. We present here a short overview of the methods followed and of the current understanding on how 90Sr was/is/will be released in the unsaturated zone and transported to the aquifer, taking into account different levels of complexity in a real environment.
N. Van Meir - One of the best experts on this subject based on the ideXlab platform.
-
Radionuclide Migration at experimental polygon at red forest waste site in chernobyl zone part 2 hydrogeological characterization and groundwater transport modeling
Applied Geochemistry, 2012Co-Authors: D. Bugai, N. Van Meir, Caroline Simonucci, S.p. Dzhepo, A. Skalskyy, Y. Kubko, V. Kashparov, D. Stammose, A MartingarinAbstract:Abstract This article represents the second of two articles, which review the main results of the international radioecological projects: Chernobyl Pilot Site Project (1999–2003) and Experimental Platform in Chernobyl (2004–2008). These projects studied Radionuclide Migration from the near-surface radioactive waste trench at the Red Forest waste dump in the Chernobyl zone, which contained nuclear fuel particles. This article presents results from the comprehensive hydrogeological site characterization program including the following issues: geological structure of the study site, hydraulic properties of the deposits, tracer tests in the aquifer, results of groundwater monitoring and unsaturated zone regime studies, as well as data on the 90Sr distribution in the unsaturated zone and aquifer, and analyses of 90Sr sorption behavior. The derived parameters were used to develop and calibrate 1D (flow tube) and 2D (cross-section) models describing the Migration of 90Sr from the studied waste trench to the unsaturated zone and aquifer over a 16-a period (1986–2002). The models involved the following sub-models: (1) the geostatistical (structural) model for radioactivity distribution in the trench (using GSLIB); and (2) the Radionuclide source term model (STERM1D) describing dissolution of fuel particles and a 1D of Radionuclide redistribution in the trench body and unsaturated zone. The MODFLOW – MT3D codes were used to model the 2D 90Sr transport in the aquifer cross-section. Calibration of the 1D model with respect to Kds and dispersivities allowed quite accurate reproduction of 90Sr Migration behavior for the early period (1995–1998). The less perfect fit between the 1D and 2D modeling results and monitoring data for the later period (1999–2002) suggests the need to improve the conceptual Radionuclide Migration model (i.e. to account for transient hydraulic and geochemical regimes of the waste site).
-
Radionuclide Migration at experimental polygon at Red Forest waste site in Chernobyl zone. Part 2 Hydrogeological characterization and groundwater transport modeling
Applied Geochemistry, 2012Co-Authors: D. Bugai, N. Van Meir, A. Skalskyy, S. Dzhepo, Y. Kubko, V. Kashparov, D. Stammose, C. Simonucci, A. Martin-garinAbstract:This article represents the second of two articles, which review the main results of the international radioecological projects Chernobyl Pilot Site Project (1999-2003) and Experimental Platform in Chernobyl (2004-2008). These projects studied Radionuclide Migration from the near-surface radioactive waste trench at the Red Forest waste dump in the Chernobyl zone, which contained nuclear fuel particles. This article presents results from the comprehensive hydrogeological site characterization program including the following issues geological structure of the study site, hydraulic properties of the deposits, tracer tests in the aquifer, results of groundwater monitoring and unsaturated zone regime studies, as well as data on the 90Sr distribution in the unsaturated zone and aquifer, and analyses of 90Sr sorption behavior. The derived parameters were used to develop and calibrate 1D (flow tube) and 2D (cross-section) models describing the Migration of 90Sr from the studied waste trench to the unsaturated zone and aquifer over a 16-a period (1986-2002). The models involved the following sub-models (1) the geostatistical (structural) model for radioactivity distribution in the trench (using GSLIB); and (2) the Radionuclide source term model (STERM1D) describing dissolution of fuel particles and a 1D of Radionuclide redistribution in the trench body and unsaturated zone. The MODFLOW - MT3D codes were used to model the 2D 90Sr transport in the aquifer cross-section. Calibration of the 1D model with respect to K ds and dispersivities allowed quite accurate reproduction of 90Sr Migration behavior for the early period (1995-1998). The less perfect fit between the 1D and 2D modeling results and monitoring data for the later period (1999-2002) suggests the need to improve the conceptual Radionuclide Migration model (i.e. to account for transient hydraulic and geochemical regimes of the waste site). © 2011 Elsevier Ltd.
-
Quantitative assessment of Radionuclide Migration from near-surface radioactive waste burial sites: the waste dumps in the Chernobyl exclusion zone as an example
Radionuclide Behaviour in the Natural Environment, 2012Co-Authors: A. Martin-garin, N. Van Meir, Caroline Simonucci, Valery Kashparov, C. Poinssot, H. GeckeisAbstract:Abstract: This chapter aims to describe the lessons learned from the studies of Radionuclide behaviour in the vicinity of the Chernobyl Nuclear Power Plant, as an example of Radionuclide Migration in a contaminated surface site. Between 1999 and 2008, we improved our understanding of the hydrogeological, geochemical and biotic processes that govern in situ Radionuclide Migration in the Red Forest waste dumps of the Chernobyl exclusion zone. We present here a short overview of the methods followed and of the current understanding on how 90Sr was/is/will be released in the unsaturated zone and transported to the aquifer, taking into account different levels of complexity in a real environment.
A Martingarin - One of the best experts on this subject based on the ideXlab platform.
-
Radionuclide Migration at experimental polygon at red forest waste site in chernobyl zone part 2 hydrogeological characterization and groundwater transport modeling
Applied Geochemistry, 2012Co-Authors: D. Bugai, N. Van Meir, Caroline Simonucci, S.p. Dzhepo, A. Skalskyy, Y. Kubko, V. Kashparov, D. Stammose, A MartingarinAbstract:Abstract This article represents the second of two articles, which review the main results of the international radioecological projects: Chernobyl Pilot Site Project (1999–2003) and Experimental Platform in Chernobyl (2004–2008). These projects studied Radionuclide Migration from the near-surface radioactive waste trench at the Red Forest waste dump in the Chernobyl zone, which contained nuclear fuel particles. This article presents results from the comprehensive hydrogeological site characterization program including the following issues: geological structure of the study site, hydraulic properties of the deposits, tracer tests in the aquifer, results of groundwater monitoring and unsaturated zone regime studies, as well as data on the 90Sr distribution in the unsaturated zone and aquifer, and analyses of 90Sr sorption behavior. The derived parameters were used to develop and calibrate 1D (flow tube) and 2D (cross-section) models describing the Migration of 90Sr from the studied waste trench to the unsaturated zone and aquifer over a 16-a period (1986–2002). The models involved the following sub-models: (1) the geostatistical (structural) model for radioactivity distribution in the trench (using GSLIB); and (2) the Radionuclide source term model (STERM1D) describing dissolution of fuel particles and a 1D of Radionuclide redistribution in the trench body and unsaturated zone. The MODFLOW – MT3D codes were used to model the 2D 90Sr transport in the aquifer cross-section. Calibration of the 1D model with respect to Kds and dispersivities allowed quite accurate reproduction of 90Sr Migration behavior for the early period (1995–1998). The less perfect fit between the 1D and 2D modeling results and monitoring data for the later period (1999–2002) suggests the need to improve the conceptual Radionuclide Migration model (i.e. to account for transient hydraulic and geochemical regimes of the waste site).
