Within the EC-funded CHANCE project several non-destructive techniques are being considered for t... more Within the EC-funded CHANCE project several non-destructive techniques are being considered for the assay of waste bearing drums. Such techniques include calorimetry, gamma-ray spectrometry and neutron coincidence counting. The aim is to quantify uncertainties on the inventory of radionuclides, and how these are potentially reduced by combining the signatures from different techniques in the data analysis. In this framework, neutron coincidence measurements were carried out with two slab counters based on 3He detectors coupled to shift register electronics. Such a system consists of two identical slabs with 6 detectors each, and is transportable, rather compact and flexible in terms of sizes and geometries that can be measured. With this system three 200 L drums containing certified reference nuclear material and different filling materials were measured. The certified nuclear material was in the form of 21 pellets of mixed oxide of U and Pu with a total mass of about 10.5 g; in add...
In Belgium, the preferred long-term management option for Eurobitum bituminized ILW is its final ... more In Belgium, the preferred long-term management option for Eurobitum bituminized ILW is its final disposal in a geologically stable clay formation such as the Boom Clay, which is studied as a reference host formation. After disposal, clay pore water will infiltrate the secondary concrete waste containers filled each with ten Eurobitum drums. Eurobitum contains hygroscopic salts, mostly NaNO3 (20-30 wt%) and CaSO4 (4-6 wt%), and thus will take up water and swell. If swelling is hindered, a pressure will be exerted on the concrete container and ultimately on the surrounding Boom Clay, possibly inducing stresses in the clay close to the disposal galleries. To improve our understanding of these processes, water uptake tests are ongoing in which inactive Eurobitum is contacted with 0.1 M KOH (representing young cement water). These tests suggest that the swelling is mainly driven by osmosis. This understanding was validated in the presented research by varying the water activity of the le...
-Effect of organic matter and organic matter together with zeolite on sorption, desorption and di... more -Effect of organic matter and organic matter together with zeolite on sorption, desorption and distribution coefficients of radiostrontium and radiocesium in different soils by Szabova, T.(Technicka Univ., Kosice (Slovakia). Katedra Upravnictva a Ochrany Zivotneho ...
... by the presence of small pores in the bitumen matrix and aggregated crystals, of which Energy... more ... by the presence of small pores in the bitumen matrix and aggregated crystals, of which Energy Dispersive X-ray analyses (EDX ... The discussions on the results and experimental set-up with Sebastià Olivella and Nadia Mokni (UPC), Xavier Sillen (ONDRAF/NIRAS * ) and ...
Integrated in situ corrosion tests with alpha-doped SON68 glass samples are performed in the HADE... more Integrated in situ corrosion tests with alpha-doped SON68 glass samples are performed in the HADES underground laboratory in Mol, Belgium. Two test tubes, bringing active glass samples in contact with three clay-based backfill materials at high density, have been dismantled. The glass and clay samples have been extensively analysed. The results on glass corrosion agree well with results from surface laboratory tests and modelling predictions. The glass alteration is two orders of magnitude higher at 90 °C than at 30 °C. The addition of powdered glass frit to a Ca-bentonite backfill reduces the glass alteration by two orders of magnitude in comparison with another backfill, dried Boom Clay. The alpha-doped glass samples had slightly thicker alteration layers. The thickness seems to increase with increasing alpha-beta-gamma activity. All backfill materials proved to be efficient barriers against radionuclide migration. The decreased glass alteration due to the addition of powdered gla...
ABSTRACT A large R&D programme has been performed to evaluate the chemical durability of ... more ABSTRACT A large R&D programme has been performed to evaluate the chemical durability of candidate high-level waste glasses in clay environments considered in Belgium. This paper discusses the methodology followed and the main results obtained over the past years. The methodology involves laboratory test set-ups focusing on the interaction with solid clay, modelling, and tests in the underground research laboratory in clay. The results discussed include dissolution rates, mobile radionuclide concentrations in the interacting solutions, analytical modelling and results from an in situ test. The results show that HLW glass will act as a substantial barrier in such an environment. The paper also discusses the main dissolution processes involved and the remaining uncertainties.
11th International Conference on Environmental Remediation and Radioactive Waste Management, Parts A and B, 2007
Description/Abstract The Belgian Nuclear Research Centre (SCK. CEN) has a long-standing expertise... more Description/Abstract The Belgian Nuclear Research Centre (SCK. CEN) has a long-standing expertise in research concerning the compatibility of waste forms with the final disposal environment. For high level waste, most attention goes to two waste forms that are ...
Integrated in situ corrosion tests with α-doped SON68 (R7T7) glass samples have been performed in... more Integrated in situ corrosion tests with α-doped SON68 (R7T7) glass samples have been performed in the HADES underground research facility in Mol, Belgium. The results on glass corrosion (effect of temperature, effect of addition of powdered glass frit, glass alteration mechanism) relate well to the expectations. Taking into account the loss of part of the alteration layer of the in situ corroded samples and the fact that the hypotheses in the model are not fully valid, the results agree also well with results from surface laboratory tests and modelling predictions with LIXIVER2. The α-doped glass samples showed slightly thicker alteration layers, and thickness seemed to increase with increasing αβγ-activity of the sample. In combination with the decreased glass alteration, the addition of powdered glass frit to a Ca-bentonite decreased the leaching of Np, Pu, and Am. In many cases, the migration profiles of these radionuclides showed a contribution of colloidal transport. Under the ...
ABSTRACT In the frame of an integrated in situ test on the alteration of the SON68 reference glas... more ABSTRACT In the frame of an integrated in situ test on the alteration of the SON68 reference glass in realistic disposal conditions, the leaching of Np, Pu, and Am from α doped SON68 glass samples and their migration in three different backfill materials at high density was measured. All backfill materials proved to be efficient barriers against radionuclide migration. The addition of powdered glass frit to Ca-bentonite clay decreased the glass alteration by two orders of magnitude, and resulted in a concomitant decrease of the radionuclide leaching in comparison with dried Boom Clay, which is the more agressive backfill. All actinides were selectively retained in the gel, but the retention degree was lower for Np than for Pu and Am.
... Res. Soc. Symp. Proc. 506, 565 – 572 (1998). 8. K. Brodersen, G. Brunel, R. Gens, F. Lambert,... more ... Res. Soc. Symp. Proc. 506, 565 – 572 (1998). 8. K. Brodersen, G. Brunel, R. Gens, F. Lambert, JC Nomine, A. Sneyers, and P. Van Iseghem, EUR 18228, European Commission, Luxembourg (1998). ... 24. SJ Fritz, Clay and Clay minerals, 43 (2), 214-223 (1986). 25. ...
Within the EC-funded CHANCE project several non-destructive techniques are being considered for t... more Within the EC-funded CHANCE project several non-destructive techniques are being considered for the assay of waste bearing drums. Such techniques include calorimetry, gamma-ray spectrometry and neutron coincidence counting. The aim is to quantify uncertainties on the inventory of radionuclides, and how these are potentially reduced by combining the signatures from different techniques in the data analysis. In this framework, neutron coincidence measurements were carried out with two slab counters based on 3He detectors coupled to shift register electronics. Such a system consists of two identical slabs with 6 detectors each, and is transportable, rather compact and flexible in terms of sizes and geometries that can be measured. With this system three 200 L drums containing certified reference nuclear material and different filling materials were measured. The certified nuclear material was in the form of 21 pellets of mixed oxide of U and Pu with a total mass of about 10.5 g; in add...
In Belgium, the preferred long-term management option for Eurobitum bituminized ILW is its final ... more In Belgium, the preferred long-term management option for Eurobitum bituminized ILW is its final disposal in a geologically stable clay formation such as the Boom Clay, which is studied as a reference host formation. After disposal, clay pore water will infiltrate the secondary concrete waste containers filled each with ten Eurobitum drums. Eurobitum contains hygroscopic salts, mostly NaNO3 (20-30 wt%) and CaSO4 (4-6 wt%), and thus will take up water and swell. If swelling is hindered, a pressure will be exerted on the concrete container and ultimately on the surrounding Boom Clay, possibly inducing stresses in the clay close to the disposal galleries. To improve our understanding of these processes, water uptake tests are ongoing in which inactive Eurobitum is contacted with 0.1 M KOH (representing young cement water). These tests suggest that the swelling is mainly driven by osmosis. This understanding was validated in the presented research by varying the water activity of the le...
-Effect of organic matter and organic matter together with zeolite on sorption, desorption and di... more -Effect of organic matter and organic matter together with zeolite on sorption, desorption and distribution coefficients of radiostrontium and radiocesium in different soils by Szabova, T.(Technicka Univ., Kosice (Slovakia). Katedra Upravnictva a Ochrany Zivotneho ...
... by the presence of small pores in the bitumen matrix and aggregated crystals, of which Energy... more ... by the presence of small pores in the bitumen matrix and aggregated crystals, of which Energy Dispersive X-ray analyses (EDX ... The discussions on the results and experimental set-up with Sebastià Olivella and Nadia Mokni (UPC), Xavier Sillen (ONDRAF/NIRAS * ) and ...
Integrated in situ corrosion tests with alpha-doped SON68 glass samples are performed in the HADE... more Integrated in situ corrosion tests with alpha-doped SON68 glass samples are performed in the HADES underground laboratory in Mol, Belgium. Two test tubes, bringing active glass samples in contact with three clay-based backfill materials at high density, have been dismantled. The glass and clay samples have been extensively analysed. The results on glass corrosion agree well with results from surface laboratory tests and modelling predictions. The glass alteration is two orders of magnitude higher at 90 °C than at 30 °C. The addition of powdered glass frit to a Ca-bentonite backfill reduces the glass alteration by two orders of magnitude in comparison with another backfill, dried Boom Clay. The alpha-doped glass samples had slightly thicker alteration layers. The thickness seems to increase with increasing alpha-beta-gamma activity. All backfill materials proved to be efficient barriers against radionuclide migration. The decreased glass alteration due to the addition of powdered gla...
ABSTRACT A large R&D programme has been performed to evaluate the chemical durability of ... more ABSTRACT A large R&D programme has been performed to evaluate the chemical durability of candidate high-level waste glasses in clay environments considered in Belgium. This paper discusses the methodology followed and the main results obtained over the past years. The methodology involves laboratory test set-ups focusing on the interaction with solid clay, modelling, and tests in the underground research laboratory in clay. The results discussed include dissolution rates, mobile radionuclide concentrations in the interacting solutions, analytical modelling and results from an in situ test. The results show that HLW glass will act as a substantial barrier in such an environment. The paper also discusses the main dissolution processes involved and the remaining uncertainties.
11th International Conference on Environmental Remediation and Radioactive Waste Management, Parts A and B, 2007
Description/Abstract The Belgian Nuclear Research Centre (SCK. CEN) has a long-standing expertise... more Description/Abstract The Belgian Nuclear Research Centre (SCK. CEN) has a long-standing expertise in research concerning the compatibility of waste forms with the final disposal environment. For high level waste, most attention goes to two waste forms that are ...
Integrated in situ corrosion tests with α-doped SON68 (R7T7) glass samples have been performed in... more Integrated in situ corrosion tests with α-doped SON68 (R7T7) glass samples have been performed in the HADES underground research facility in Mol, Belgium. The results on glass corrosion (effect of temperature, effect of addition of powdered glass frit, glass alteration mechanism) relate well to the expectations. Taking into account the loss of part of the alteration layer of the in situ corroded samples and the fact that the hypotheses in the model are not fully valid, the results agree also well with results from surface laboratory tests and modelling predictions with LIXIVER2. The α-doped glass samples showed slightly thicker alteration layers, and thickness seemed to increase with increasing αβγ-activity of the sample. In combination with the decreased glass alteration, the addition of powdered glass frit to a Ca-bentonite decreased the leaching of Np, Pu, and Am. In many cases, the migration profiles of these radionuclides showed a contribution of colloidal transport. Under the ...
ABSTRACT In the frame of an integrated in situ test on the alteration of the SON68 reference glas... more ABSTRACT In the frame of an integrated in situ test on the alteration of the SON68 reference glass in realistic disposal conditions, the leaching of Np, Pu, and Am from α doped SON68 glass samples and their migration in three different backfill materials at high density was measured. All backfill materials proved to be efficient barriers against radionuclide migration. The addition of powdered glass frit to Ca-bentonite clay decreased the glass alteration by two orders of magnitude, and resulted in a concomitant decrease of the radionuclide leaching in comparison with dried Boom Clay, which is the more agressive backfill. All actinides were selectively retained in the gel, but the retention degree was lower for Np than for Pu and Am.
... Res. Soc. Symp. Proc. 506, 565 – 572 (1998). 8. K. Brodersen, G. Brunel, R. Gens, F. Lambert,... more ... Res. Soc. Symp. Proc. 506, 565 – 572 (1998). 8. K. Brodersen, G. Brunel, R. Gens, F. Lambert, JC Nomine, A. Sneyers, and P. Van Iseghem, EUR 18228, European Commission, Luxembourg (1998). ... 24. SJ Fritz, Clay and Clay minerals, 43 (2), 214-223 (1986). 25. ...
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