... Résumé / Abstract. Predicting the amount of water that may seep into waste emplacement drifts... more ... Résumé / Abstract. Predicting the amount of water that may seep into waste emplacement drifts is important for assessing the performance of the proposed geologic repository for spent nuclearfuel and high-level radioactive waste at Yucca Mountain, Nevada. ...
Food-grade CO2 was injected into a shallow aquifer through a perforated pipe placed horizontally ... more Food-grade CO2 was injected into a shallow aquifer through a perforated pipe placed horizontally 1–2 m below the water table at the Montana State University Zero Emission Research and Technology (MSU-ZERT) field site at Bozeman, Montana. The possible impact of elevated CO2 levels on groundwater quality was investigated by analyzing 80 water samples taken before, during, and following CO2 injection. Field
Approximately 300 kg/day of food-grade CO2 was injected through a perforated pipe placed horizont... more Approximately 300 kg/day of food-grade CO2 was injected through a perforated pipe placed horizontally 2-2.3 m deep during July 9-August 7, 2008 at the MSU-ZERT field test to evaluate atmospheric and near- surface monitoring and detection techniques applicable to the subsurface storage and potential leakage of CO2. As part of this multidisciplinary research project, we collected 80 samples of water
Prediction of the amount of water that may seep into the waste emplacement drifts is an important... more Prediction of the amount of water that may seep into the waste emplacement drifts is an important aspect of assessing the performance of the proposed geologic nuclear waste repository at Yucca Mountain, Nevada. The repository is to be located in thick, partially saturated fractured tuff that will be heated to above-boiling temperatures as a result of heat generation from the decay of nuclear waste. Since water percolating down towards the repository will be subject to vigorous boiling for a significant time period, the superheated rock zone (i.e., rock temperature above the boiling point of water) can form an effective vaporization barrier that reduces the possibility of water arrival at emplacement drifts. In this paper, we analyze the behavior of episodic preferential flow events that penetrate the hot fractured rock, and we evaluate the impact of such flow behavior on the effectiveness of the vaporization barrier.
An important factor for the performance of the potential nuclear waste repository at Yucca Mounta... more An important factor for the performance of the potential nuclear waste repository at Yucca Mountain, Nevada, is the amount of water seeping into the emplacement drifts. During the first thousand years after emplacement, a superheated rock region is predicted to form around the tunnels as a result of heat generation from the nuclear waste. In this rock region, vigorous vaporization will form a barrier that can significantly reduce the possibility of water contacting the waste packages. The performance of this barrier depends on the nature of flow in the unsaturated fractured rock. Episodic infiltration events flowing in localized preferential flow paths may penetrate far into the superheated rock to eventually reach the emplacement drifts. This differs from results obtained with spatially and temporally averaged infiltration conditions where potential penetration distances are typically underestimated. In this paper, the probability of episodic infiltration reaching waste packages du...
This paper describes numerical prediction of the coupled thermal-hydrological processes (TH) in t... more This paper describes numerical prediction of the coupled thermal-hydrological processes (TH) in the vicinity of waste emplacement drifts during the heating phase of the proposed geologic repository for nuclear waste at Yucca Mountain, Nevada. Heating of rock water to above-boiling conditions induces water saturation changes and perturbed water fluxes that affect the potential of water seepage into drifts. In addition to the capillary barrier at the rock-drift interface--independent of the thermal conditions--a second barrier exists to downward percolation at above-boiling conditions. This barrier is caused by vaporization of water in the fractured rock overlying the repository. A TOUGH2 simulation model was developed to analyze the combined effect of these two barriers; it accounts for all relevant TH processes in response to heating, while incorporating the capillary barrier condition at the drift wall. Model results are presented for a variety of simulation cases.
Aside from the target storage regions being underground, geologic carbon sequestration and radioa... more Aside from the target storage regions being underground, geologic carbon sequestration and radioactive waste disposal share little in common in North America. The large volume of carbon dioxide (CO2) needed to be sequestered along with its relatively benign health effects present a sharp contrast to the limited volumes and hazardous nature of high-level radioactive waste. There is welldocumented capacity in North America for 100 years or more of sequestration of CO2 from coalfired power plants. Aside from economics, the challenges of geologic carbon sequestration include lack of fully established legal and regulatory framework for ownership of injected CO2, the need for an expanded pipeline infrastructure, and public acceptance of the technology. As for radioactive waste, the U.S. has proposed the unsaturated tuffs of Yucca Mountain, Nevada, as the region’s first high-level radioactive waste disposal site. The Canadian radioactive waste program is currently evolving with options tha...
While the purpose of geologic storage of CO{sub 2} in deep saline formations is to trap greenhous... more While the purpose of geologic storage of CO{sub 2} in deep saline formations is to trap greenhouse gases underground, the potential exists for CO{sub 2} to escape from the target reservoir, migrate upward along permeable pathways, and discharge at the land surface. Such discharge is not necessarily a serious concern, as CO{sub 2} is a naturally abundant and relatively benign gas in low concentrations. However, there is a potential risk to health, safety and environment (HSE) in the event that large localized fluxes of CO{sub 2} were to occur at the land surface, especially where CO{sub 2} could accumulate. In this paper, we develop possible scenarios for large CO{sub 2} fluxes based on the analysis of natural analogues, where large releases of gas have been observed. We are particularly interested in scenarios which could generate sudden, possibly self-enhancing, or even eruptive release events. The probability for such events may be low, but the circumstances under which they might...
Predicting the amount of water that may seep into waste emplacement drifts is important for asses... more Predicting the amount of water that may seep into waste emplacement drifts is important for assessing the performance of the proposed geologic repository for high-level radioactive waste at Yucca Mountain, Nevada. The repository would be located in thick, partially saturated fractured tuff that will be heated to above-boiling temperatures as a result of heat generation from the decay of nuclear waste. Since infiltrating water will be subject to vigorous boiling for a significant time period, the superheated rock zone (i.e., rock temperature above the boiling point of water) can form an effective vaporization barrier that reduces the possibility of water arrival at emplacement drifts. In this paper, we analyze the behavior of episodic preferential flow events that penetrate the hot fractured rock, evaluate the impact of such flow behavior on the effectiveness of the vaporization barrier, and discuss the implications for the performance assessment of the repository. A semi-analytical ...
... Résumé / Abstract. Predicting the amount of water that may seep into waste emplacement drifts... more ... Résumé / Abstract. Predicting the amount of water that may seep into waste emplacement drifts is important for assessing the performance of the proposed geologic repository for spent nuclearfuel and high-level radioactive waste at Yucca Mountain, Nevada. ...
Food-grade CO2 was injected into a shallow aquifer through a perforated pipe placed horizontally ... more Food-grade CO2 was injected into a shallow aquifer through a perforated pipe placed horizontally 1–2 m below the water table at the Montana State University Zero Emission Research and Technology (MSU-ZERT) field site at Bozeman, Montana. The possible impact of elevated CO2 levels on groundwater quality was investigated by analyzing 80 water samples taken before, during, and following CO2 injection. Field
Approximately 300 kg/day of food-grade CO2 was injected through a perforated pipe placed horizont... more Approximately 300 kg/day of food-grade CO2 was injected through a perforated pipe placed horizontally 2-2.3 m deep during July 9-August 7, 2008 at the MSU-ZERT field test to evaluate atmospheric and near- surface monitoring and detection techniques applicable to the subsurface storage and potential leakage of CO2. As part of this multidisciplinary research project, we collected 80 samples of water
Prediction of the amount of water that may seep into the waste emplacement drifts is an important... more Prediction of the amount of water that may seep into the waste emplacement drifts is an important aspect of assessing the performance of the proposed geologic nuclear waste repository at Yucca Mountain, Nevada. The repository is to be located in thick, partially saturated fractured tuff that will be heated to above-boiling temperatures as a result of heat generation from the decay of nuclear waste. Since water percolating down towards the repository will be subject to vigorous boiling for a significant time period, the superheated rock zone (i.e., rock temperature above the boiling point of water) can form an effective vaporization barrier that reduces the possibility of water arrival at emplacement drifts. In this paper, we analyze the behavior of episodic preferential flow events that penetrate the hot fractured rock, and we evaluate the impact of such flow behavior on the effectiveness of the vaporization barrier.
An important factor for the performance of the potential nuclear waste repository at Yucca Mounta... more An important factor for the performance of the potential nuclear waste repository at Yucca Mountain, Nevada, is the amount of water seeping into the emplacement drifts. During the first thousand years after emplacement, a superheated rock region is predicted to form around the tunnels as a result of heat generation from the nuclear waste. In this rock region, vigorous vaporization will form a barrier that can significantly reduce the possibility of water contacting the waste packages. The performance of this barrier depends on the nature of flow in the unsaturated fractured rock. Episodic infiltration events flowing in localized preferential flow paths may penetrate far into the superheated rock to eventually reach the emplacement drifts. This differs from results obtained with spatially and temporally averaged infiltration conditions where potential penetration distances are typically underestimated. In this paper, the probability of episodic infiltration reaching waste packages du...
This paper describes numerical prediction of the coupled thermal-hydrological processes (TH) in t... more This paper describes numerical prediction of the coupled thermal-hydrological processes (TH) in the vicinity of waste emplacement drifts during the heating phase of the proposed geologic repository for nuclear waste at Yucca Mountain, Nevada. Heating of rock water to above-boiling conditions induces water saturation changes and perturbed water fluxes that affect the potential of water seepage into drifts. In addition to the capillary barrier at the rock-drift interface--independent of the thermal conditions--a second barrier exists to downward percolation at above-boiling conditions. This barrier is caused by vaporization of water in the fractured rock overlying the repository. A TOUGH2 simulation model was developed to analyze the combined effect of these two barriers; it accounts for all relevant TH processes in response to heating, while incorporating the capillary barrier condition at the drift wall. Model results are presented for a variety of simulation cases.
Aside from the target storage regions being underground, geologic carbon sequestration and radioa... more Aside from the target storage regions being underground, geologic carbon sequestration and radioactive waste disposal share little in common in North America. The large volume of carbon dioxide (CO2) needed to be sequestered along with its relatively benign health effects present a sharp contrast to the limited volumes and hazardous nature of high-level radioactive waste. There is welldocumented capacity in North America for 100 years or more of sequestration of CO2 from coalfired power plants. Aside from economics, the challenges of geologic carbon sequestration include lack of fully established legal and regulatory framework for ownership of injected CO2, the need for an expanded pipeline infrastructure, and public acceptance of the technology. As for radioactive waste, the U.S. has proposed the unsaturated tuffs of Yucca Mountain, Nevada, as the region’s first high-level radioactive waste disposal site. The Canadian radioactive waste program is currently evolving with options tha...
While the purpose of geologic storage of CO{sub 2} in deep saline formations is to trap greenhous... more While the purpose of geologic storage of CO{sub 2} in deep saline formations is to trap greenhouse gases underground, the potential exists for CO{sub 2} to escape from the target reservoir, migrate upward along permeable pathways, and discharge at the land surface. Such discharge is not necessarily a serious concern, as CO{sub 2} is a naturally abundant and relatively benign gas in low concentrations. However, there is a potential risk to health, safety and environment (HSE) in the event that large localized fluxes of CO{sub 2} were to occur at the land surface, especially where CO{sub 2} could accumulate. In this paper, we develop possible scenarios for large CO{sub 2} fluxes based on the analysis of natural analogues, where large releases of gas have been observed. We are particularly interested in scenarios which could generate sudden, possibly self-enhancing, or even eruptive release events. The probability for such events may be low, but the circumstances under which they might...
Predicting the amount of water that may seep into waste emplacement drifts is important for asses... more Predicting the amount of water that may seep into waste emplacement drifts is important for assessing the performance of the proposed geologic repository for high-level radioactive waste at Yucca Mountain, Nevada. The repository would be located in thick, partially saturated fractured tuff that will be heated to above-boiling temperatures as a result of heat generation from the decay of nuclear waste. Since infiltrating water will be subject to vigorous boiling for a significant time period, the superheated rock zone (i.e., rock temperature above the boiling point of water) can form an effective vaporization barrier that reduces the possibility of water arrival at emplacement drifts. In this paper, we analyze the behavior of episodic preferential flow events that penetrate the hot fractured rock, evaluate the impact of such flow behavior on the effectiveness of the vaporization barrier, and discuss the implications for the performance assessment of the repository. A semi-analytical ...
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Papers by Jens Birkholzer