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Blair P Bromley - One of the best experts on this subject based on the ideXlab platform.
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physics characteristics of internally cooled annular fuel for potential application in pressure tube Heavy Water Reactors
Annals of Nuclear Energy, 2019Co-Authors: Blair P Bromley, Ashlea V Colton, K Groves, S GolesorkhiAbstract:Abstract This paper summarizes the results of exploratory lattice physics studies of alternative, advanced fuel bundle concepts that could potentially be implemented in pressure tube Heavy Water Reactors (PT-HWRs). The lattice physics code WIMS-AECL was used to analyze the physics performance and operational characteristics of an 18-element and a 12-element internally cooled annular fuel (ICAF) fuel bundle, made with (LEU,Th)O2 fuel, with both low-burnup and high-burnup options. Such fuel bundles with annular fuel elements may be able to operate at higher bundle power levels and with higher linear element (LER) ratings than fuel bundles with conventional solid cylindrical fuel elements. In addition, the use of thorium mixed with LEU can help extend uranium resources, exploit the energy potential in thorium, and also reduce the production of plutonium and minor actinides, due to the smaller fraction of 238U in the fuel. The influence of improvements in the neutron economy of these lattices was also investigated, by incorporating higher-purity Heavy Water moderator and coolant (99.90 at.% D2O) in the models, along with enriched zirconium (95 wt% 90Zr/Zr) for the zirconium alloys used in the structural components. The results were compared with those for a more conventional 37-element PT-HWR fuel bundle using natural uranium (NU) fuel. Results show that annular fuels could be very attractive, being able to achieve higher burnup, comparable or better fissile utilization, reduced coolant void reactivity, and comparable or more negative fuel temperature coefficients.
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a canadian perspective of the economic issues associated with deploying thorium based fuel cycles and breeding in Heavy Water Reactors
CNL Nuclear Review, 2019Co-Authors: Alberto Mendoza D Espana, Blair P BromleyAbstract:To meet future global needs for energy and green technology, it is prudent to identify energy sources and technology that may potentially be economically beneficial. Thorium-based fuels with nuclear technology, such as the Canadian Heavy-Water reactor, have been proposed as a way to meet those global needs, though economic challenges persist in deploying thorium-based fuels. Therefore, economic strategies to overcome the economic challenges in deploying thorium-based fuels are needed. To identify potential strategies for advancing the deployment of thorium-based fuels, this paper conducts a historical examination of the economics of thorium fuel cycles to identify economic factors that can influence a country’s development of thorium-based fuel cycles. In particular, this paper reviews the economic issues associated with Canada’s experience in deploying thorium-based fuel cycles. The study finds that the existence of natural resources and the associated price, a nuclear fuel cycle’s costs, a country’s int...
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Modeling and mitigation of bundle end power peaking in pressure tube Heavy Water reactor advanced fuels using thorium dioxide
Annals of Nuclear Energy, 2018Co-Authors: Clifford Dugal, Ashlea V Colton, S Golesorkhi, Blair P BromleyAbstract:Abstract Fuel bundle end power peaking in pressure tube Heavy Water Reactors (PT-HWRs), particularly considering advanced reactor fuels (such as thorium-based fuels), was evaluated and a mitigation method was assessed. For bundles containing all the same fuel pellets, power is greatest at the bundle ends due to higher thermal neutron flux there. A method to achieve a flatter axial power profile along a bundle by downblending the fissile content in the end pellets with thorium dioxide was evaluated. The method was shown to be effective, and only a slight reduction in fresh fuel reactivity was observed.
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lattice physics evaluation of 35 element mixed oxide thorium based fuels for use in pressure tube Heavy Water Reactors
Annals of Nuclear Energy, 2018Co-Authors: Ashlea V Colton, Blair P BromleyAbstract:Abstract A series of 2-D lattice physics calculations with depletion were carried with WIMS-AECL Version 3.1 out as part of exploratory scoping studies to evaluate various thorium-based fuel bundle concepts for potential application in pressure tube Heavy Water Reactors (PT-HWRs). Fuel bundles concepts investigated consisted of a cluster of 35 fuel elements arranged in two rings (14 + 21), and surrounding a central graphite displacer rod. The fuel is comprised of thorium dioxide mixed with a fissile driver of reactor-grade plutonium (∼67 wt% Pu fissile /Pu; 3.5–4.5 wt% PuO 2 /(Pu,Th)O 2 ), low enriched uranium (5 wt% 235 U/U; 40–50 wt% LEUO 2 /(LEU,Th)O 2 ) or uranium–233 (1.8 wt% 233 UO 2 /( 233 U,Th)O 2 ). Estimates of burnup-averaged fuel temperature coefficients (FTC) and coolant void reactivity (CVR) were found to be lower than those for conventional natural uranium dioxide (NUO 2 ) PT-HWR fuel in a 37-element bundle. A low-burnup option for using (LEU,Th)O 2 fuel in a PT-HWR is found to be attractive as a means for extracting energy from thorium, while also generating stockpiles of 233 U, and demonstrating enhanced safety characteristics with reduced CVR and FTC relative to NUO 2 .
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power level effects on thorium based fuels in pressure tube Heavy Water Reactors
CNL Nuclear Review, 2016Co-Authors: Blair P Bromley, Geoffrey W R Edwards, Pranavan SambavalingamAbstract:Lattice and core physics modeling and calculations have been performed to quantify the impact of power/flux levels on the reactivity and achievable burnup for 35-element fuel bundles made with Pu/Th or U-233/Th. The fissile content in these bundles has been adjusted to produce on the order of 20 MWd/kg burnup in homogeneous cores in a 700 MWe-class pressure-tube Heavy Water reactor, operating on a once-through thorium cycle. Results demonstrate that the impact of the power/flux level is modest for Pu/Th fuels but significant for U-233/Th fuels. In particular, high power/flux reduces the breeding and burnup potential of U-233/Th fuels. Thus, there may be an incentive to operate Reactors with U-233/Th fuels at a lower power density or to develop alternative refueling schemes that will lower the time-average specific power, thereby increasing burnup.
Ashlea V Colton - One of the best experts on this subject based on the ideXlab platform.
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physics characteristics of internally cooled annular fuel for potential application in pressure tube Heavy Water Reactors
Annals of Nuclear Energy, 2019Co-Authors: Blair P Bromley, Ashlea V Colton, K Groves, S GolesorkhiAbstract:Abstract This paper summarizes the results of exploratory lattice physics studies of alternative, advanced fuel bundle concepts that could potentially be implemented in pressure tube Heavy Water Reactors (PT-HWRs). The lattice physics code WIMS-AECL was used to analyze the physics performance and operational characteristics of an 18-element and a 12-element internally cooled annular fuel (ICAF) fuel bundle, made with (LEU,Th)O2 fuel, with both low-burnup and high-burnup options. Such fuel bundles with annular fuel elements may be able to operate at higher bundle power levels and with higher linear element (LER) ratings than fuel bundles with conventional solid cylindrical fuel elements. In addition, the use of thorium mixed with LEU can help extend uranium resources, exploit the energy potential in thorium, and also reduce the production of plutonium and minor actinides, due to the smaller fraction of 238U in the fuel. The influence of improvements in the neutron economy of these lattices was also investigated, by incorporating higher-purity Heavy Water moderator and coolant (99.90 at.% D2O) in the models, along with enriched zirconium (95 wt% 90Zr/Zr) for the zirconium alloys used in the structural components. The results were compared with those for a more conventional 37-element PT-HWR fuel bundle using natural uranium (NU) fuel. Results show that annular fuels could be very attractive, being able to achieve higher burnup, comparable or better fissile utilization, reduced coolant void reactivity, and comparable or more negative fuel temperature coefficients.
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Modeling and mitigation of bundle end power peaking in pressure tube Heavy Water reactor advanced fuels using thorium dioxide
Annals of Nuclear Energy, 2018Co-Authors: Clifford Dugal, Ashlea V Colton, S Golesorkhi, Blair P BromleyAbstract:Abstract Fuel bundle end power peaking in pressure tube Heavy Water Reactors (PT-HWRs), particularly considering advanced reactor fuels (such as thorium-based fuels), was evaluated and a mitigation method was assessed. For bundles containing all the same fuel pellets, power is greatest at the bundle ends due to higher thermal neutron flux there. A method to achieve a flatter axial power profile along a bundle by downblending the fissile content in the end pellets with thorium dioxide was evaluated. The method was shown to be effective, and only a slight reduction in fresh fuel reactivity was observed.
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lattice physics evaluation of 35 element mixed oxide thorium based fuels for use in pressure tube Heavy Water Reactors
Annals of Nuclear Energy, 2018Co-Authors: Ashlea V Colton, Blair P BromleyAbstract:Abstract A series of 2-D lattice physics calculations with depletion were carried with WIMS-AECL Version 3.1 out as part of exploratory scoping studies to evaluate various thorium-based fuel bundle concepts for potential application in pressure tube Heavy Water Reactors (PT-HWRs). Fuel bundles concepts investigated consisted of a cluster of 35 fuel elements arranged in two rings (14 + 21), and surrounding a central graphite displacer rod. The fuel is comprised of thorium dioxide mixed with a fissile driver of reactor-grade plutonium (∼67 wt% Pu fissile /Pu; 3.5–4.5 wt% PuO 2 /(Pu,Th)O 2 ), low enriched uranium (5 wt% 235 U/U; 40–50 wt% LEUO 2 /(LEU,Th)O 2 ) or uranium–233 (1.8 wt% 233 UO 2 /( 233 U,Th)O 2 ). Estimates of burnup-averaged fuel temperature coefficients (FTC) and coolant void reactivity (CVR) were found to be lower than those for conventional natural uranium dioxide (NUO 2 ) PT-HWR fuel in a 37-element bundle. A low-burnup option for using (LEU,Th)O 2 fuel in a PT-HWR is found to be attractive as a means for extracting energy from thorium, while also generating stockpiles of 233 U, and demonstrating enhanced safety characteristics with reduced CVR and FTC relative to NUO 2 .
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evaluation of uranium based fuels augmented by low levels of thorium for near term implementation in pressure tube Heavy Water Reactors
Nuclear Science and Engineering, 2017Co-Authors: Ashlea V Colton, Blair P Bromley, Daniel Wojtaszek, Clifford DugalAbstract:AbstractThorium, a fertile nuclear fuel that is nearly three times as abundant as uranium, represents a long-term energy source that could complement uranium and eventually replace it. To facilitate the gradual transition from uranium-based fuels to thorium-based fuels, it may be advantageous in the near term to introduce small amounts of thorium (˂7% of the total fuel mass) into uranium-based fuels in pressure tube Heavy Water Reactors (PT-HWRs). Downblending natural or slightly enriched uranium dioxide with thorium dioxide for fuel pellets placed at the ends of the fuel stack of a conventional 37-element fuel bundle could help reduce axial power peaking for fresh fuel, while incorporating thorium dioxide into the central element of the fuel bundle could reduce coolant void reactivity (CVR).A series of two-dimensional lattice physics simulations was carried out as part of conceptual scoping studies to evaluate the potential performance and safety characteristics of uranium-based fuel bundles with small a...
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performance improvements for thorium based fuels in pressure tube Heavy Water Reactors
CNL Nuclear Review, 2017Co-Authors: Blair P Bromley, Ashlea V Colton, Owen CollinsAbstract:Lattice physics sensitivity studies have been performed with WIMS-AECL to quantify the impact of various design and operating parameters on the performance characteristics of thorium-based fuel concepts in pressure-tube Heavy-Water Reactors. Fuels modeled included 37-element bundles with natural uranium oxide (for comparison), pure thorium oxide (blanket-type fuel) and 35-element bundles of mixed oxide with thorium and U-233. Key performance parameters evaluated included the lattice reactivity, exit burnup, coolant void reactivity (CVR), and fissile concentration. The effects of various design/operational parameters were evaluated, including calandria tube radius, moderator purity, coolant purity, zirconium enrichment, and temporary out-of-core fuel storage at zero power. Results demonstrated that removing the moderator around the blanket fuel can harden the neutron energy spectrum and increase the discharge fissile content from ∼1 wt% U-233 to ∼2 wt% U-233 at a low discharge burnup (5 MWd/kg). Increasing...
B P Kashyap - One of the best experts on this subject based on the ideXlab platform.
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Effect of processing on properties of thin walled calandria tubes for pressurised Heavy Water reactor
Journal of Nuclear Materials, 2020Co-Authors: K Kapoor, T Sanyal, C. Padmaprabu, S.v Ramana Rao, B P KashyapAbstract:Thin walled calandria tubes for pressurised Heavy Water Reactors are manufactured either by seam welding of Zircaloy-4 sheets or by seamless route. In the present study, the effect of processing on the critical properties such as texture, microstructure, hydriding behaviour and residual stress for both the routes as well as the mechanical anisotropy developed due to seam welding are investigated. The properties of the seam welded tube in the fusion and adjoining region are markedly different from the base material and from the seamless tube. Residual stress measurements indicate that heat affected zone (HAZ) of seam welded tubes have longitudinal tensile residual stress and the seamless tubes have uniform compressive stress along the circumference. The phase transition in the presence of residual stresses due to thermal gradient is found to modify the texture in the HAZ. The hydride orientation and mechanical anisotropy in these regions are found to be dependent on the texture of the material.© Elsevie
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Effect of processing on properties of thin walled calandria tubes for pressurised Heavy Water reactor
Journal of Nuclear Materials, 2003Co-Authors: K Kapoor, T Sanyal, C. Padmaprabu, B P KashyapAbstract:Thin walled calandria tubes for pressurised Heavy Water Reactors are manufactured either by seam welding of Zircaloy-4 sheets or by seamless route. In the present study, the effect of processing on the critical properties such as texture, microstructure, hydriding behaviour and residual stress for both the routes as well as the mechanical anisotropy developed due to seam welding are investigated. The properties of the seam welded tube in the fusion and adjoining region are markedly different from the base material and from the seamless tube. Residual stress measurements indicate that heat affected zone (HAZ) of seam welded tubes have longitudinal tensile residual stress and the seamless tubes have uniform compressive stress along the circumference. The phase transition in the presence of residual stresses due to thermal gradient is found to modify the texture in the HAZ. The hydride orientation and mechanical anisotropy in these regions are found to be dependent on the texture of the material.
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texture measurement in zr 2 5 nb pressure tubes for pressurized Heavy Water Reactors
Journal of Testing and Evaluation, 2003Co-Authors: K Kapoor, T Sanyal, B P KashyapAbstract:Preferred orientation or crystallographic texture of Zr-2.5%Nb pressure tubes for a pressurized Heavy Water reactor (PHWR) affects all the critical in-reactor properties. The preferred orientation has to be measured to standardize the process route for getting the desired in-reactor properties. The quantitative determination involves determination of the complete pole figure and calculation of Kearns parameters from the pole figure data. Independently, neither the X-ray reflection nor the X-ray transmission technique can provide the full pole figure data. The literature reports only partial pole figures. Quantification of texture based on partial pole figures may lead to errors in estimation. For a complete pole figure determination, it is required to merge the data from both the reflection and the transmission techniques. This requires a special test setup that can combine the pole figure data obtained from the two techniques. In this paper, a methodology for determination of the complete pole figure with quantitative texture parameters for Zr-2.5%Nb pressure tubes is reported.
Blair P Bromley - One of the best experts on this subject based on the ideXlab platform.
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evaluation of uranium based fuels augmented by low levels of thorium for near term implementation in pressure tube Heavy Water Reactors
Nuclear Science and Engineering, 2017Co-Authors: Ashlea V Colton, Blair P Bromley, Daniel Wojtaszek, Clifford DugalAbstract:AbstractThorium, a fertile nuclear fuel that is nearly three times as abundant as uranium, represents a long-term energy source that could complement uranium and eventually replace it. To facilitate the gradual transition from uranium-based fuels to thorium-based fuels, it may be advantageous in the near term to introduce small amounts of thorium (˂7% of the total fuel mass) into uranium-based fuels in pressure tube Heavy Water Reactors (PT-HWRs). Downblending natural or slightly enriched uranium dioxide with thorium dioxide for fuel pellets placed at the ends of the fuel stack of a conventional 37-element fuel bundle could help reduce axial power peaking for fresh fuel, while incorporating thorium dioxide into the central element of the fuel bundle could reduce coolant void reactivity (CVR).A series of two-dimensional lattice physics simulations was carried out as part of conceptual scoping studies to evaluate the potential performance and safety characteristics of uranium-based fuel bundles with small a...
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performance improvements for thorium based fuels in pressure tube Heavy Water Reactors
CNL Nuclear Review, 2017Co-Authors: Blair P Bromley, Ashlea V Colton, Owen CollinsAbstract:Lattice physics sensitivity studies have been performed with WIMS-AECL to quantify the impact of various design and operating parameters on the performance characteristics of thorium-based fuel concepts in pressure-tube Heavy-Water Reactors. Fuels modeled included 37-element bundles with natural uranium oxide (for comparison), pure thorium oxide (blanket-type fuel) and 35-element bundles of mixed oxide with thorium and U-233. Key performance parameters evaluated included the lattice reactivity, exit burnup, coolant void reactivity (CVR), and fissile concentration. The effects of various design/operational parameters were evaluated, including calandria tube radius, moderator purity, coolant purity, zirconium enrichment, and temporary out-of-core fuel storage at zero power. Results demonstrated that removing the moderator around the blanket fuel can harden the neutron energy spectrum and increase the discharge fissile content from ∼1 wt% U-233 to ∼2 wt% U-233 at a low discharge burnup (5 MWd/kg). Increasing...
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full core evaluation of uranium based fuels augmented with small amounts of thorium in pressure tube Heavy Water Reactors
Nuclear Technology, 2016Co-Authors: Ashlea V Colton, Blair P BromleyAbstract:AbstractThorium, a fertile nuclear fuel that is nearly three times as abundant as uranium, represents a long-term energy source that could complement uranium and eventually replace it. With the expected refurbishment and new construction of pressure tube Heavy Water Reactors (PT-HWRs) within the international community, there is an opportunity to gain experience with thorium-based fuels and to start the transition toward the use of thorium as part of the nuclear fuel cycle.This paper presents an evaluation of fuel types that could be implemented in the near-term to transition into thorium-based fuels in current PT-HWRs. The near-term fuel consists of small amounts of thorium (in a traditional 37-element fuel bundle that is mostly filled with natural uranium or slightly enriched uranium). In addition, a modified 37-element fuel bundle type comprised of slightly enriched uranium fuel (1.2 wt% 235U/U or less), a thorium central element, and the mass equivalent of 1-cm thorium end pellets was studied. Both la...
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heterogeneous seed blanket cores in pressure tube Heavy Water Reactors for extracting the energy potential from plutonium thorium fuels
CNL Nuclear Review, 2016Co-Authors: Blair P BromleyAbstract:Pressure-tube Heavy Water Reactors (PT-HWR) are advantageous for implementing plutonium/thorium fuels because of their online refuelling capability and high neutron economy. The use of annular seed–blanket core concepts in a PT-HWR where higher fissile-content seed fuel bundles are physically separate from lower fissile-content blanket bundles allows more flexibility in fuel management. The bundle concept modeled was a 35-element fuel bundle made with a mixture of reactor grade PuO2 (~67 wt% fissile) and ThO2, with a central zirconia rod to reduce coolant void reactivity. Eight annular heterogeneous seed-blanket core concepts with plutonium/thorium-based fuels in a 700 MWe-class PT-HWR were analyzed, using a once-through thorium cycle. Blanket region(s) represented approximately 50% of the total fuel volume. There were 1–4 different blanket regions and 1–4 different seed regions. The seed fuel tested was 3 wt% or 4 wt% PuO2, whereas the blanket fuel tested was 1 wt% or 2 wt% PuO2, mixed with ThO2. For com...
Tae Young Kong - One of the best experts on this subject based on the ideXlab platform.
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an analysis of workers tritium concentration in urine samples as a function of time after intake at korean pressurised Heavy Water Reactors
Radiation Protection Dosimetry, 2012Co-Authors: Tae Young KongAbstract:: In general, internal exposure from tritium at pressurised Heavy Water Reactors (PHWRs) accounts for ∼20-40 % of the total radiation dose. Tritium usually reaches the equilibrium concentration after a few hours inside the body and is then excreted from the body with an effective half-life in the order of 10 d. In this study, tritium metabolism was reviewed using its excretion rate in urine samples of workers at Korean PHWRs. The tritium concentration in workers' urine samples was also measured as a function of time after intake. On the basis of the monitoring results, changes in the tritium concentration inside the body were then analysed.
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analysis of metabolism and effective half life for radiation workers tritium intake at pressurized Heavy Water Reactors
2011Co-Authors: Tae Young Kong, Woo Tae JeongAbstract:Tritium is the one of the dominant contributors to the workers of Pressurized Heavy Water Reactors’ (PHWRs) internal radiation exposure. This nuclide is likely to be released in work places as tritiated Water vapor (HTO) from the primary system and can get relatively easily absorbed into the body of workers by inhalation. Inhaled tritium usually reaches the equilibrium of concentration after approximately 2 hours inside the body and is then excreted from the body with an effective half-life of 10 days. Because the tritium inside the body is transported within the body, the whole body can be exposed to radiation. Internal radiation exposure at PHWRs accounts for approximately 20-40 % of the total radiation exposure, where most of the internal radiation exposure is attributed to tritium. Thus, tritium is an important nuclide that needs to be necessarily monitored for radiation management safety. In this study, metabolism for tritium was established by using its excretion rate results in urine samples of workers at PHWRs. An effective half-life, a key parameter that estimates the radiation exposure, was derived from these results. As a result, it was found that the effective half-life for workers at Korean Nuclear Power Plants (NPPs) was 7.43 2.22 days, which is shorter than that of International Commission on Radiological Protection guides.
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an internal tritium concentration analysis in urine samples as a function of submission time after airborne tritium intake at korean pressurized Heavy Water Reactors
Journal of Radiation Protection and Research, 2009Co-Authors: Tae Young Kong, Woo Tae JeongAbstract:In pressurized Heavy Water Reactors, workers who enter radiation controlled areas must submit their urine samples to health physicists after radiation work; these samples are then used to monitor internal radiation exposure from tritium intake. This procedure assumes that the samples submitted represent tritium concentration inside the body at equilibrium. According to both technical reports from the International Commission on Radiological Protection and experimental results from Canadian nuclear utilities, tritium inside the body generally reaches equilibrium concentration after approximately 2-3 hours of intake. In practice, urine samples can be submitted either before the 2 hours mark or after several hours of radiation work because of the numerous tasks that workers must perform and their frequent entries during nuclear power plant maintenance. In this paper, tritium concentration in workers' urine samples was measured as a function of time submitted after radiation work. Based on the measurement results, changes in the tritium concentration inside the body and its effect on internal dose assessment were then analyzed. As a result, it was found that tritium concentration reaches equilibrium concentration before the 2 hours mark for most workers' urine samples.