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Deze masterproef kadert in een onderzoeksproject, uitgevoerd door SCK•CEN, waarbij gezocht wordt ... more Deze masterproef kadert in een onderzoeksproject, uitgevoerd door SCK•CEN, waarbij gezocht wordt naar een geschikt afvalvat voor de opberging van de met tritium besmette tegels uit fusiereactoren. Het afvalvat wordt zodanig ontworpen dat het ontsnappen van tritium tot een minimum herleid wordt. Aangezien tritium een zeer klein atoom is, bezit het de eigenschap vrij gemakkelijk doorheen materialen te diffunderen. De afsluiting van het vat van de buitenwereld vormt het meest cruciale onderdeel. In de experimenten werden 2 soorten afdichtingen getest: elastomere O-ringen en metalen C-ringen. Als elastomere O-ringen werden 4 materialen onderzocht: epichlorohydrinerubber (ECO), broombutylrubber (BIIR), Viton® 75 en nitrilerubber (NBR). Als metalen afdichtingen werd geopteerd voor C-ringen met veerondersteuning. De C-ringen waren vervaardigd uit de een nikkel-chroomlegering "Inconel X-750" met een zilver- of kopercoating. Uit de experimenten is af te leiden dat de metalen C-ring...

Deze bachelorproef is uitgevoerd in functie van een masterproef, die de toepasbaarheid van quadru... more Deze bachelorproef is uitgevoerd in functie van een masterproef, die de toepasbaarheid van quadrupool inductief gekoppeld plasma massaspectrometrie bij de bepaling van zes radionucliden behandelt. De zes radionucliden zijnde: ijzer 55, nikkel 59, nikkel 69, niobium 96, technetium 99, jood 129. Deze bachelorproef haalt het verschil aan tussen quadrupool ICP-MS en sector veld ICP-MS en bekijkt welke interferenties eventueel kunnen vermeden worden door het gebruik van hoge resolutie.

In dit onderzoek is getracht om het genucleariseerd ICP-MS toestel van het SCK•CEN te karakterise... more In dit onderzoek is getracht om het genucleariseerd ICP-MS toestel van het SCK•CEN te karakteriseren, met als doel de langlevende radionucliden 55Fe, 59Ni, 63Ni, 94Nb, 99Tc en 129I te detecteren. Gaandeweg is de nadruk gelegd op koud plasma techniek, een techniek die in het verleden reeds gebruikt werd voor de detectie van stabiele isotopen. Hierbij wordt een plasma met een laag RF vermogen toegepast zodat argongebaseerde interferenties afkomstig uit het plasma beperkt blijven. Deze techniek is onderzocht voor 55Fe, 59Ni en 63Ni omdat deze voldoen aan de hoofdvereiste voor het gebruik van koud plasma techniek, namelijk een lage ionisatie-energie zodat ze nog voldoende geïoniseerd worden in het koude plasma. Dit onderzoek toont aan dat koud plasma, in combinatie met een eenvoudige scheidingsprocedure, een veelbelovende techniek is voor de detectie van deze drie radionucliden. Door de scheiding worden de isobare interferenties geïsoleerd die onmogelijk instrumenteel te reduceren zijn....

Het SCK•CEN bezit zelf een hoeveelheid van 90 liter besmet en geactiveerd natrium. De momenteel b... more Het SCK•CEN bezit zelf een hoeveelheid van 90 liter besmet en geactiveerd natrium. De momenteel beschikbare processen maken gebruik van de reactie water-natrium. Deze voldoet, volgens het SCK•CEN niet aan het ALARA-principe. Het SCK•CEN wilde daarom zelf een oplossing vinden voor de verwerking van dit natriumafval. Het onderzoek werd opgestart door de Wamibox-groep (SANDS-proces) en het doel was om het natrium gecontroleerd te injecteren in een met zand (SiO2) gevulde wervelbedreactor. Het “SANDS-proces”, bestaat uit 2 apart uit te voeren reacties namelijk, een oxidatie met zuurstof tot natriumoxide gevolgd door een carbonatatie met koolstofdioxide tot vorming van natriumcarbonaat. Door de hoogoplopende kosten en de vele technische problemen besliste deze groep om het onderzoek te stoppen. Het onderzoek werd overgenomen door FUCHEM. Op basis van de ervaring van deze onderzoeksgroep werd beslist om gebruik te maken van een reactor met mechanisch aangedreven roerder. Dit project kreeg...

Ground water, Jan 6, 2015

Due to differences in hydraulic conductivity and effects of well construction geometry, groundwat... more Due to differences in hydraulic conductivity and effects of well construction geometry, groundwater lateral flow through a monitoring well typically differs from groundwater flow in the surrounding aquifer. These differences must be well understood in order to apply passive measuring techniques, such as passive flux meters (PFMs) used for the measurement of groundwater and contaminant mass fluxes. To understand these differences, lab flow tank experiments were performed to evaluate the influences of the well screen, the surrounding filter pack and the presence of a PFM on the natural groundwater flux through a monitoring well. The results were compared with analytical calculations of flow field distortion based on the potential theory of Drost et al. (1968). Measured well flow field distortion factors were found to be lower than calculated flow field distortion factors, while measured PFM flow field distortion factors were comparable to the calculated ones. However, this latter is n...

Environmental Geochemistry and Health, 2012

A site-and receptor-specific risk management strategy for groundwater pollution based on the meas... more A site-and receptor-specific risk management strategy for groundwater pollution based on the measurement of contaminant mass flux is proposed. The approach is useful and compatible with the demands formulated in the European Water Framework Directive, its Groundwater Daughter Directive and the regulations applicable in the EU member states. The proposed CMF method focuses on the following: (1) capture zones, (2) the location of control planes, (3) the definition of the maximum allowed contaminant mass discharge and (4) contaminant mass flux measurements. For every control plane, such a maximum allowed contaminant mass discharge is derived and is crucial for the receptor risk management strategy. The method is demonstrated for a large area of groundwater pollution present in the industrial area of Vilvoorde-Machelen located in Flanders, Belgium.

This study comprises the first application of the Passive Flux Meter (PFM) for the measurement of... more This study comprises the first application of the Passive Flux Meter (PFM) for the measurement of chlorinated aliphatic hydrocarbon (CAH) mass fluxes and Darcy water fluxes in groundwater at a European field site. The PFM was originally developed and applied to measurements near source zones. The focus of the PFM is extended from near source to plume zones. For this purpose, 48 PFMs of 1.4 m length were constructed and installed in eight different monitoring wells in the source and plume zone of a CAH-contaminated field site located in France. The PFMs were retrieved, sampled, and analyzed after 3 to 11 weeks of exposure time, depending on the expected contaminant flux. PFM evaluation criteria include analytical, technical, and practical aspects as well as conditions and applicability. PFM flux data were compared with so-called traditional soil and groundwater concentration data obtained using active sampling methods. The PFMs deliver reasonable results for source as well as plume zones. The limiting factor in the PFM applicability is the exposure time together with the groundwater flux. Measured groundwater velocities at the field site range from 2 to 41 cm/day. Measured contaminant flux data raise up to 13 g/m 2 /day for perchloroethylene in the plume zone. Calculated PFM flux averaged concentration data and traditional concentration data were of similar magnitude for most wells. However, both datasets need to be compared with reservation because of the different sampling nature and time. Two important issues are the PFM tracer loss during installation/extraction and the deviation of the groundwater flow field when passing the monitoring well and PFM. The demonstration of the PFM at a CAHcontaminated field site in Europe confirmed the efficiency of the flux measurement technique for source as well as plume zones. The PFM can be applied without concerns in monitoring wells with European standards. The acquired flux data are of great value for the purpose of site characterization and mass discharge modeling, and can be used in combination with traditional soil and groundwater sampling methods.

Ground Water Monitoring and Remediation, 2010

Measurement and interpretation of mass fluxes in favor of concentrations is gaining more and more... more Measurement and interpretation of mass fluxes in favor of concentrations is gaining more and more interest, especially within the framework of the characterization and management of large-scale volatile organic carbon (VOC) groundwater contamination (source zones and plumes). Traditional methods of estimating contaminant fluxes and discharges involve individual measurements/calculations of the Darcy water flux and the contaminant concentrations. However, taken into account the spatially and temporally varying hydrologic conditions in complex, heterogeneous aquifers, higher uncertainty arises from such indirect estimation of contaminant fluxes. Therefore, the potential use of passive sampling devices for the direct measurement of groundwater-related VOC mass fluxes is examined. A review of current passive samplers for the measurement of organic contaminants in water yielded the selection of 18 samplers that were screened for a number of criteria. These criteria are related to the possible application of the sampler for the measurement of VOC mass fluxes in groundwater. This screening study indicates that direct measurement of VOC mass fluxes in groundwater is possible with very few passive samplers. Currently, the passive flux meter (PFM) is the only passive sampler which has proven to effectively measure mass fluxes in near source groundwater. A passive sampler for mass flux measurement in plume zones with regard to long-term monitoring (several months to a year) still needs to be developed or optimized. A passive sampler for long-term monitoring of contaminant mass fluxes in groundwater would be of considerable value in the development of risk-based assessment and management of soil and groundwater pollutions.

The Journal of Physical Chemistry, 1984

... We also thank Professor Dino S. Tinti for the high-resolution phos-phorescence spectra of the... more ... We also thank Professor Dino S. Tinti for the high-resolution phos-phorescence spectra of the samples of adsorbed molecules taken at liquid helium temperatures. ... Paul Vanderauwera,t Franz C. DeSchryver,t Albert Weller,$ Mitchell A. Winnik,s and Klaas A. Zachariasse*$ ...

Bio-oil resulting from the pyrolysis of lignocellulose is a complex mixture of polar low molecula... more Bio-oil resulting from the pyrolysis of lignocellulose is a complex mixture of polar low molecular mass oxygenated compounds of various functionalities and non-polar high molecular mass lignin derivatives. Several approaches to the upgrading of bio-oil are currently in progress. This study investigates the valorisation of crude bio-oil using physical and chemical methods. The effects of methanol addition on some properties of the bio-oil are investigated. Stable bio-oil/diesel oil emulsions are produced by the addition of surfactants with a hydrophilic-lipophilic balance value of 5-6. An alternative approach towards the upgrading of bio-oil is the hydrotreatment of the water-soluble fraction of bio-oil. Two-stage hydroprocessing with noble-metal catalysts Ru/C and Pt/C increases the intrinsic hydrogen content of the water-soluble fraction. The results show that the thermally unstable components including sugars, ketones and aldehydes are readily converted to diols and alcohols at pressures of 5 MPa. These observations can be explained by a set of reaction pathways for the compounds identified.

Deze masterproef kadert in een onderzoeksproject, uitgevoerd door SCK•CEN, waarbij gezocht wordt ... more Deze masterproef kadert in een onderzoeksproject, uitgevoerd door SCK•CEN, waarbij gezocht wordt naar een geschikt afvalvat voor de opberging van de met tritium besmette tegels uit fusiereactoren. Het afvalvat wordt zodanig ontworpen dat het ontsnappen van tritium tot een minimum herleid wordt. Aangezien tritium een zeer klein atoom is, bezit het de eigenschap vrij gemakkelijk doorheen materialen te diffunderen. De afsluiting van het vat van de buitenwereld vormt het meest cruciale onderdeel. In de experimenten werden 2 soorten afdichtingen getest: elastomere O-ringen en metalen C-ringen. Als elastomere O-ringen werden 4 materialen onderzocht: epichlorohydrinerubber (ECO), broombutylrubber (BIIR), Viton® 75 en nitrilerubber (NBR). Als metalen afdichtingen werd geopteerd voor C-ringen met veerondersteuning. De C-ringen waren vervaardigd uit de een nikkel-chroomlegering "Inconel X-750" met een zilver- of kopercoating. Uit de experimenten is af te leiden dat de metalen C-ring...

Deze bachelorproef is uitgevoerd in functie van een masterproef, die de toepasbaarheid van quadru... more Deze bachelorproef is uitgevoerd in functie van een masterproef, die de toepasbaarheid van quadrupool inductief gekoppeld plasma massaspectrometrie bij de bepaling van zes radionucliden behandelt. De zes radionucliden zijnde: ijzer 55, nikkel 59, nikkel 69, niobium 96, technetium 99, jood 129. Deze bachelorproef haalt het verschil aan tussen quadrupool ICP-MS en sector veld ICP-MS en bekijkt welke interferenties eventueel kunnen vermeden worden door het gebruik van hoge resolutie.

In dit onderzoek is getracht om het genucleariseerd ICP-MS toestel van het SCK•CEN te karakterise... more In dit onderzoek is getracht om het genucleariseerd ICP-MS toestel van het SCK•CEN te karakteriseren, met als doel de langlevende radionucliden 55Fe, 59Ni, 63Ni, 94Nb, 99Tc en 129I te detecteren. Gaandeweg is de nadruk gelegd op koud plasma techniek, een techniek die in het verleden reeds gebruikt werd voor de detectie van stabiele isotopen. Hierbij wordt een plasma met een laag RF vermogen toegepast zodat argongebaseerde interferenties afkomstig uit het plasma beperkt blijven. Deze techniek is onderzocht voor 55Fe, 59Ni en 63Ni omdat deze voldoen aan de hoofdvereiste voor het gebruik van koud plasma techniek, namelijk een lage ionisatie-energie zodat ze nog voldoende geïoniseerd worden in het koude plasma. Dit onderzoek toont aan dat koud plasma, in combinatie met een eenvoudige scheidingsprocedure, een veelbelovende techniek is voor de detectie van deze drie radionucliden. Door de scheiding worden de isobare interferenties geïsoleerd die onmogelijk instrumenteel te reduceren zijn....

Het SCK•CEN bezit zelf een hoeveelheid van 90 liter besmet en geactiveerd natrium. De momenteel b... more Het SCK•CEN bezit zelf een hoeveelheid van 90 liter besmet en geactiveerd natrium. De momenteel beschikbare processen maken gebruik van de reactie water-natrium. Deze voldoet, volgens het SCK•CEN niet aan het ALARA-principe. Het SCK•CEN wilde daarom zelf een oplossing vinden voor de verwerking van dit natriumafval. Het onderzoek werd opgestart door de Wamibox-groep (SANDS-proces) en het doel was om het natrium gecontroleerd te injecteren in een met zand (SiO2) gevulde wervelbedreactor. Het “SANDS-proces”, bestaat uit 2 apart uit te voeren reacties namelijk, een oxidatie met zuurstof tot natriumoxide gevolgd door een carbonatatie met koolstofdioxide tot vorming van natriumcarbonaat. Door de hoogoplopende kosten en de vele technische problemen besliste deze groep om het onderzoek te stoppen. Het onderzoek werd overgenomen door FUCHEM. Op basis van de ervaring van deze onderzoeksgroep werd beslist om gebruik te maken van een reactor met mechanisch aangedreven roerder. Dit project kreeg...

Ground water, Jan 6, 2015

Due to differences in hydraulic conductivity and effects of well construction geometry, groundwat... more Due to differences in hydraulic conductivity and effects of well construction geometry, groundwater lateral flow through a monitoring well typically differs from groundwater flow in the surrounding aquifer. These differences must be well understood in order to apply passive measuring techniques, such as passive flux meters (PFMs) used for the measurement of groundwater and contaminant mass fluxes. To understand these differences, lab flow tank experiments were performed to evaluate the influences of the well screen, the surrounding filter pack and the presence of a PFM on the natural groundwater flux through a monitoring well. The results were compared with analytical calculations of flow field distortion based on the potential theory of Drost et al. (1968). Measured well flow field distortion factors were found to be lower than calculated flow field distortion factors, while measured PFM flow field distortion factors were comparable to the calculated ones. However, this latter is n...

Environmental Geochemistry and Health, 2012

A site-and receptor-specific risk management strategy for groundwater pollution based on the meas... more A site-and receptor-specific risk management strategy for groundwater pollution based on the measurement of contaminant mass flux is proposed. The approach is useful and compatible with the demands formulated in the European Water Framework Directive, its Groundwater Daughter Directive and the regulations applicable in the EU member states. The proposed CMF method focuses on the following: (1) capture zones, (2) the location of control planes, (3) the definition of the maximum allowed contaminant mass discharge and (4) contaminant mass flux measurements. For every control plane, such a maximum allowed contaminant mass discharge is derived and is crucial for the receptor risk management strategy. The method is demonstrated for a large area of groundwater pollution present in the industrial area of Vilvoorde-Machelen located in Flanders, Belgium.

This study comprises the first application of the Passive Flux Meter (PFM) for the measurement of... more This study comprises the first application of the Passive Flux Meter (PFM) for the measurement of chlorinated aliphatic hydrocarbon (CAH) mass fluxes and Darcy water fluxes in groundwater at a European field site. The PFM was originally developed and applied to measurements near source zones. The focus of the PFM is extended from near source to plume zones. For this purpose, 48 PFMs of 1.4 m length were constructed and installed in eight different monitoring wells in the source and plume zone of a CAH-contaminated field site located in France. The PFMs were retrieved, sampled, and analyzed after 3 to 11 weeks of exposure time, depending on the expected contaminant flux. PFM evaluation criteria include analytical, technical, and practical aspects as well as conditions and applicability. PFM flux data were compared with so-called traditional soil and groundwater concentration data obtained using active sampling methods. The PFMs deliver reasonable results for source as well as plume zones. The limiting factor in the PFM applicability is the exposure time together with the groundwater flux. Measured groundwater velocities at the field site range from 2 to 41 cm/day. Measured contaminant flux data raise up to 13 g/m 2 /day for perchloroethylene in the plume zone. Calculated PFM flux averaged concentration data and traditional concentration data were of similar magnitude for most wells. However, both datasets need to be compared with reservation because of the different sampling nature and time. Two important issues are the PFM tracer loss during installation/extraction and the deviation of the groundwater flow field when passing the monitoring well and PFM. The demonstration of the PFM at a CAHcontaminated field site in Europe confirmed the efficiency of the flux measurement technique for source as well as plume zones. The PFM can be applied without concerns in monitoring wells with European standards. The acquired flux data are of great value for the purpose of site characterization and mass discharge modeling, and can be used in combination with traditional soil and groundwater sampling methods.

Ground Water Monitoring and Remediation, 2010

Measurement and interpretation of mass fluxes in favor of concentrations is gaining more and more... more Measurement and interpretation of mass fluxes in favor of concentrations is gaining more and more interest, especially within the framework of the characterization and management of large-scale volatile organic carbon (VOC) groundwater contamination (source zones and plumes). Traditional methods of estimating contaminant fluxes and discharges involve individual measurements/calculations of the Darcy water flux and the contaminant concentrations. However, taken into account the spatially and temporally varying hydrologic conditions in complex, heterogeneous aquifers, higher uncertainty arises from such indirect estimation of contaminant fluxes. Therefore, the potential use of passive sampling devices for the direct measurement of groundwater-related VOC mass fluxes is examined. A review of current passive samplers for the measurement of organic contaminants in water yielded the selection of 18 samplers that were screened for a number of criteria. These criteria are related to the possible application of the sampler for the measurement of VOC mass fluxes in groundwater. This screening study indicates that direct measurement of VOC mass fluxes in groundwater is possible with very few passive samplers. Currently, the passive flux meter (PFM) is the only passive sampler which has proven to effectively measure mass fluxes in near source groundwater. A passive sampler for mass flux measurement in plume zones with regard to long-term monitoring (several months to a year) still needs to be developed or optimized. A passive sampler for long-term monitoring of contaminant mass fluxes in groundwater would be of considerable value in the development of risk-based assessment and management of soil and groundwater pollutions.

The Journal of Physical Chemistry, 1984

... We also thank Professor Dino S. Tinti for the high-resolution phos-phorescence spectra of the... more ... We also thank Professor Dino S. Tinti for the high-resolution phos-phorescence spectra of the samples of adsorbed molecules taken at liquid helium temperatures. ... Paul Vanderauwera,t Franz C. DeSchryver,t Albert Weller,$ Mitchell A. Winnik,s and Klaas A. Zachariasse*$ ...

Bio-oil resulting from the pyrolysis of lignocellulose is a complex mixture of polar low molecula... more Bio-oil resulting from the pyrolysis of lignocellulose is a complex mixture of polar low molecular mass oxygenated compounds of various functionalities and non-polar high molecular mass lignin derivatives. Several approaches to the upgrading of bio-oil are currently in progress. This study investigates the valorisation of crude bio-oil using physical and chemical methods. The effects of methanol addition on some properties of the bio-oil are investigated. Stable bio-oil/diesel oil emulsions are produced by the addition of surfactants with a hydrophilic-lipophilic balance value of 5-6. An alternative approach towards the upgrading of bio-oil is the hydrotreatment of the water-soluble fraction of bio-oil. Two-stage hydroprocessing with noble-metal catalysts Ru/C and Pt/C increases the intrinsic hydrogen content of the water-soluble fraction. The results show that the thermally unstable components including sugars, ketones and aldehydes are readily converted to diols and alcohols at pressures of 5 MPa. These observations can be explained by a set of reaction pathways for the compounds identified.