The Experts below are selected from a list of 168 Experts worldwide ranked by ideXlab platform
Adem Acir - One of the best experts on this subject based on the ideXlab platform.
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commercial utilization of weapon grade plutonium as triso fuel in conventional candu reactors
Energy Conversion and Management, 2012Co-Authors: Sumer şahin, Haci Mehmet şahin, Adem AcirAbstract:Abstract Large quantities of weapon grade (WG) plutonium have been accumulated in the nuclear warheads. Plutonium and heavy water moderator can give a good combination with respect to Neutron Economy. TRISO type fuel can withstand very high fuel burn up levels. The paper investigates the prospects of utilization of TRISO fuel made of WG-plutonium in CANDU reactors. Three different fuel compositions have been investigated: (1): 90% ThC + 10% PuC, (2): 70% ThC + 30% PuC and (3): 50% ThC + 50% PuC. The temporal variation of the criticality k∞ and the burn-up values of the reactor have been calculated by full power operation up to 17 years. Calculated startup criticalities for these fuel modes are k∞,0 = 1.6403, 1.7228 and 1.7662, respectively. Attainable burn up values and reactor operation times without new fuel charge will be 94 700, 265 000 and 425 000 MW.D/MT and along with continuous operation periods of ∼3.5, 10 and 17 years, respectively, for the corresponding modes. These high burn ups would reduce fuel fabrication costs and nuclear waste mass for final disposal per unit energy drastically.
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utilization of triso fuel with reactor grade plutonium in candu reactors
Nuclear Engineering and Design, 2010Co-Authors: Sumer şahin, Haci Mehmet şahin, Adem AcirAbstract:Abstract Large quantities of plutonium have been accumulated in the nuclear waste of civilian LWRs and CANDU reactors. Reactor grade plutonium and heavy water moderator can give a good combination with respect to Neutron Economy. On the other hand, TRISO type fuel can withstand very high fuel burn-up levels. The paper investigates the prospects of utilization of TRISO fuel made of reactor grade plutonium in CANDU reactors. TRISO fuels particles are imbedded body-centered cubic (BCC) in a graphite matrix with a volume fraction of 68%. The fuel compacts conform to the dimensions of CANDU fuel compacts are inserted in rods with zircolay cladding. In the first phase of investigations, five new mixed fuel have been selected for CANDU reactors composed of 4% RG-PuO 2 + 96% ThO 2 ; 6% RG-PuO 2 + 94% ThO 2 ; 10% RG-PuO 2 + 90% ThO 2 ; 20% RG-PuO 2 + 80% ThO 2 ; 30% RG-PuO 2 + 70% ThO 2 . Initial reactor criticality ( k ∞,0 values) for the modes , , , and are calculated as 1.4294, 1.5035, 1.5678, 1.6249, and 1.6535, respectively. Corresponding operation lifetimes are ∼0.65, 1.1, 1.9, 3.5, and 4.8 years and with burn ups of ∼30 000, 60 000, 100 000, 200 000 and 290 000 MW d/tonne, respectively. The higher initial plutonium charge is the higher burn ups can be achieved. In the second phase, a graphical-numerical power flattening procedure has been applied with radially variable mixed fuel composition in the fuel bundle. Mixed fuel fractions leading to quasi-constant power production are found in the 1st, 2nd, 3rd and 4th row to be as 100% PuO 2 , 80/20% PuO 2 /ThO 2 , 60/40% PuO 2 /ThO 2 , and 40/60% PuO 2 /ThO 2 , respectively. Higher plutonium amount in the flattened case increases reactor operation lifetime to >8 years and the burn up to 580 000 MW d/tonne. Power flattening in the bundle leads to higher power plant factor and quasi-uniform fuel utilization, reduces thermal and material stresses, and avoids local thermal peaks. Extended burn-up grade implies drastic reduction of the nuclear waste material per unit energy output for final waste disposal.
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Criticality investigations for the fixed bed nuclear reactor using thorium fuel mixed with plutonium or minor actinides
Annals of Nuclear Energy, 2009Co-Authors: Sumer şahin, Haci Mehmet şahin, Adem Acir, Tawfik A. Al-kusayerAbstract:Prospective fuels for a new reactor type, the so called fixed bed nuclear reactor (FBNR) are investigated with respect to reactor criticality. These are r low enriched uranium (LEU); s weapon grade plutonium + ThO2; t reactor grade plutonium + ThO2; and u minor actinides in the spent fuel of light water reactors (LWRs) + ThO2. Reactor grade plutonium and minor actinides are considered as highly radioactive and radio-toxic nuclear waste products so that one can expect that they will have negative fuel costs. The criticality calculations are conducted with SCALE5.1 using S8–P3 approximation in 238 Neutron energy groups with 90 groups in thermal energy region. The study has shown that the reactor criticality has lower values with uranium fuel and increases passing to minor actinides, reactor grade plutonium and weapon grade plutonium. Using LEU, an enrichment grade of 9% has resulted with keff = 1.2744. Mixed fuel with weapon grade plutonium made of 20% PuO2 + 80% ThO2 yields keff = 1.2864. Whereas a mixed fuel with reactor grade plutonium made of 35% PuO2 + 65% ThO2 brings it to keff = 1.267. Even the very hazardous nuclear waste of LWRs, namely minor actinides turn out to be high quality nuclear fuel due to the excellent Neutron Economy of FBNR. A relatively high reactor criticality of keff = 1.2673 is achieved by 50% MAO2 + 50% ThO2.
Sumer şahin - One of the best experts on this subject based on the ideXlab platform.
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commercial utilization of weapon grade plutonium as triso fuel in conventional candu reactors
Energy Conversion and Management, 2012Co-Authors: Sumer şahin, Haci Mehmet şahin, Adem AcirAbstract:Abstract Large quantities of weapon grade (WG) plutonium have been accumulated in the nuclear warheads. Plutonium and heavy water moderator can give a good combination with respect to Neutron Economy. TRISO type fuel can withstand very high fuel burn up levels. The paper investigates the prospects of utilization of TRISO fuel made of WG-plutonium in CANDU reactors. Three different fuel compositions have been investigated: (1): 90% ThC + 10% PuC, (2): 70% ThC + 30% PuC and (3): 50% ThC + 50% PuC. The temporal variation of the criticality k∞ and the burn-up values of the reactor have been calculated by full power operation up to 17 years. Calculated startup criticalities for these fuel modes are k∞,0 = 1.6403, 1.7228 and 1.7662, respectively. Attainable burn up values and reactor operation times without new fuel charge will be 94 700, 265 000 and 425 000 MW.D/MT and along with continuous operation periods of ∼3.5, 10 and 17 years, respectively, for the corresponding modes. These high burn ups would reduce fuel fabrication costs and nuclear waste mass for final disposal per unit energy drastically.
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utilization of triso fuel with reactor grade plutonium in candu reactors
Nuclear Engineering and Design, 2010Co-Authors: Sumer şahin, Haci Mehmet şahin, Adem AcirAbstract:Abstract Large quantities of plutonium have been accumulated in the nuclear waste of civilian LWRs and CANDU reactors. Reactor grade plutonium and heavy water moderator can give a good combination with respect to Neutron Economy. On the other hand, TRISO type fuel can withstand very high fuel burn-up levels. The paper investigates the prospects of utilization of TRISO fuel made of reactor grade plutonium in CANDU reactors. TRISO fuels particles are imbedded body-centered cubic (BCC) in a graphite matrix with a volume fraction of 68%. The fuel compacts conform to the dimensions of CANDU fuel compacts are inserted in rods with zircolay cladding. In the first phase of investigations, five new mixed fuel have been selected for CANDU reactors composed of 4% RG-PuO 2 + 96% ThO 2 ; 6% RG-PuO 2 + 94% ThO 2 ; 10% RG-PuO 2 + 90% ThO 2 ; 20% RG-PuO 2 + 80% ThO 2 ; 30% RG-PuO 2 + 70% ThO 2 . Initial reactor criticality ( k ∞,0 values) for the modes , , , and are calculated as 1.4294, 1.5035, 1.5678, 1.6249, and 1.6535, respectively. Corresponding operation lifetimes are ∼0.65, 1.1, 1.9, 3.5, and 4.8 years and with burn ups of ∼30 000, 60 000, 100 000, 200 000 and 290 000 MW d/tonne, respectively. The higher initial plutonium charge is the higher burn ups can be achieved. In the second phase, a graphical-numerical power flattening procedure has been applied with radially variable mixed fuel composition in the fuel bundle. Mixed fuel fractions leading to quasi-constant power production are found in the 1st, 2nd, 3rd and 4th row to be as 100% PuO 2 , 80/20% PuO 2 /ThO 2 , 60/40% PuO 2 /ThO 2 , and 40/60% PuO 2 /ThO 2 , respectively. Higher plutonium amount in the flattened case increases reactor operation lifetime to >8 years and the burn up to 580 000 MW d/tonne. Power flattening in the bundle leads to higher power plant factor and quasi-uniform fuel utilization, reduces thermal and material stresses, and avoids local thermal peaks. Extended burn-up grade implies drastic reduction of the nuclear waste material per unit energy output for final waste disposal.
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Criticality investigations for the fixed bed nuclear reactor using thorium fuel mixed with plutonium or minor actinides
Annals of Nuclear Energy, 2009Co-Authors: Sumer şahin, Haci Mehmet şahin, Adem Acir, Tawfik A. Al-kusayerAbstract:Prospective fuels for a new reactor type, the so called fixed bed nuclear reactor (FBNR) are investigated with respect to reactor criticality. These are r low enriched uranium (LEU); s weapon grade plutonium + ThO2; t reactor grade plutonium + ThO2; and u minor actinides in the spent fuel of light water reactors (LWRs) + ThO2. Reactor grade plutonium and minor actinides are considered as highly radioactive and radio-toxic nuclear waste products so that one can expect that they will have negative fuel costs. The criticality calculations are conducted with SCALE5.1 using S8–P3 approximation in 238 Neutron energy groups with 90 groups in thermal energy region. The study has shown that the reactor criticality has lower values with uranium fuel and increases passing to minor actinides, reactor grade plutonium and weapon grade plutonium. Using LEU, an enrichment grade of 9% has resulted with keff = 1.2744. Mixed fuel with weapon grade plutonium made of 20% PuO2 + 80% ThO2 yields keff = 1.2864. Whereas a mixed fuel with reactor grade plutonium made of 35% PuO2 + 65% ThO2 brings it to keff = 1.267. Even the very hazardous nuclear waste of LWRs, namely minor actinides turn out to be high quality nuclear fuel due to the excellent Neutron Economy of FBNR. A relatively high reactor criticality of keff = 1.2673 is achieved by 50% MAO2 + 50% ThO2.
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, Sourena 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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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...
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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...
Haci Mehmet şahin - One of the best experts on this subject based on the ideXlab platform.
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commercial utilization of weapon grade plutonium as triso fuel in conventional candu reactors
Energy Conversion and Management, 2012Co-Authors: Sumer şahin, Haci Mehmet şahin, Adem AcirAbstract:Abstract Large quantities of weapon grade (WG) plutonium have been accumulated in the nuclear warheads. Plutonium and heavy water moderator can give a good combination with respect to Neutron Economy. TRISO type fuel can withstand very high fuel burn up levels. The paper investigates the prospects of utilization of TRISO fuel made of WG-plutonium in CANDU reactors. Three different fuel compositions have been investigated: (1): 90% ThC + 10% PuC, (2): 70% ThC + 30% PuC and (3): 50% ThC + 50% PuC. The temporal variation of the criticality k∞ and the burn-up values of the reactor have been calculated by full power operation up to 17 years. Calculated startup criticalities for these fuel modes are k∞,0 = 1.6403, 1.7228 and 1.7662, respectively. Attainable burn up values and reactor operation times without new fuel charge will be 94 700, 265 000 and 425 000 MW.D/MT and along with continuous operation periods of ∼3.5, 10 and 17 years, respectively, for the corresponding modes. These high burn ups would reduce fuel fabrication costs and nuclear waste mass for final disposal per unit energy drastically.
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utilization of triso fuel with reactor grade plutonium in candu reactors
Nuclear Engineering and Design, 2010Co-Authors: Sumer şahin, Haci Mehmet şahin, Adem AcirAbstract:Abstract Large quantities of plutonium have been accumulated in the nuclear waste of civilian LWRs and CANDU reactors. Reactor grade plutonium and heavy water moderator can give a good combination with respect to Neutron Economy. On the other hand, TRISO type fuel can withstand very high fuel burn-up levels. The paper investigates the prospects of utilization of TRISO fuel made of reactor grade plutonium in CANDU reactors. TRISO fuels particles are imbedded body-centered cubic (BCC) in a graphite matrix with a volume fraction of 68%. The fuel compacts conform to the dimensions of CANDU fuel compacts are inserted in rods with zircolay cladding. In the first phase of investigations, five new mixed fuel have been selected for CANDU reactors composed of 4% RG-PuO 2 + 96% ThO 2 ; 6% RG-PuO 2 + 94% ThO 2 ; 10% RG-PuO 2 + 90% ThO 2 ; 20% RG-PuO 2 + 80% ThO 2 ; 30% RG-PuO 2 + 70% ThO 2 . Initial reactor criticality ( k ∞,0 values) for the modes , , , and are calculated as 1.4294, 1.5035, 1.5678, 1.6249, and 1.6535, respectively. Corresponding operation lifetimes are ∼0.65, 1.1, 1.9, 3.5, and 4.8 years and with burn ups of ∼30 000, 60 000, 100 000, 200 000 and 290 000 MW d/tonne, respectively. The higher initial plutonium charge is the higher burn ups can be achieved. In the second phase, a graphical-numerical power flattening procedure has been applied with radially variable mixed fuel composition in the fuel bundle. Mixed fuel fractions leading to quasi-constant power production are found in the 1st, 2nd, 3rd and 4th row to be as 100% PuO 2 , 80/20% PuO 2 /ThO 2 , 60/40% PuO 2 /ThO 2 , and 40/60% PuO 2 /ThO 2 , respectively. Higher plutonium amount in the flattened case increases reactor operation lifetime to >8 years and the burn up to 580 000 MW d/tonne. Power flattening in the bundle leads to higher power plant factor and quasi-uniform fuel utilization, reduces thermal and material stresses, and avoids local thermal peaks. Extended burn-up grade implies drastic reduction of the nuclear waste material per unit energy output for final waste disposal.
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Criticality investigations for the fixed bed nuclear reactor using thorium fuel mixed with plutonium or minor actinides
Annals of Nuclear Energy, 2009Co-Authors: Sumer şahin, Haci Mehmet şahin, Adem Acir, Tawfik A. Al-kusayerAbstract:Prospective fuels for a new reactor type, the so called fixed bed nuclear reactor (FBNR) are investigated with respect to reactor criticality. These are r low enriched uranium (LEU); s weapon grade plutonium + ThO2; t reactor grade plutonium + ThO2; and u minor actinides in the spent fuel of light water reactors (LWRs) + ThO2. Reactor grade plutonium and minor actinides are considered as highly radioactive and radio-toxic nuclear waste products so that one can expect that they will have negative fuel costs. The criticality calculations are conducted with SCALE5.1 using S8–P3 approximation in 238 Neutron energy groups with 90 groups in thermal energy region. The study has shown that the reactor criticality has lower values with uranium fuel and increases passing to minor actinides, reactor grade plutonium and weapon grade plutonium. Using LEU, an enrichment grade of 9% has resulted with keff = 1.2744. Mixed fuel with weapon grade plutonium made of 20% PuO2 + 80% ThO2 yields keff = 1.2864. Whereas a mixed fuel with reactor grade plutonium made of 35% PuO2 + 65% ThO2 brings it to keff = 1.267. Even the very hazardous nuclear waste of LWRs, namely minor actinides turn out to be high quality nuclear fuel due to the excellent Neutron Economy of FBNR. A relatively high reactor criticality of keff = 1.2673 is achieved by 50% MAO2 + 50% ThO2.
Andrew R Mount - One of the best experts on this subject based on the ideXlab platform.
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demand driven salt clean up in a molten salt fast reactor defining a priority list
PLOS ONE, 2018Co-Authors: Bruno Merk, Dzianis Litskevich, Robert Gregg, Andrew R MountAbstract:The PUREX technology based on aqueous processes is currently the leading reprocessing technology in nuclear energy systems. It seems to be the most developed and established process for light water reactor fuel and the use of solid fuel. However, demand driven development of the nuclear system opens the way to liquid fuelled reactors, and disruptive technology development through the application of an integrated fuel cycle with a direct link to reactor operation. The possibilities of this new concept for innovative reprocessing technology development are analysed, the boundary conditions are discussed, and the economic as well as the Neutron physical optimization parameters of the process are elucidated. Reactor physical knowledge of the influence of different elements on the Neutron Economy of the reactor is required. Using an innovative study approach, an element priority list for the salt clean-up is developed, which indicates that separation of Neodymium and Caesium is desirable, as they contribute almost 50% to the loss of criticality. Separating Zirconium and Samarium in addition from the fuel salt would remove nearly 80% of the loss of criticality due to fission products. The theoretical study is followed by a qualitative discussion of the different, demand driven optimization strategies which could satisfy the conflicting interests of sustainable reactor operation, efficient chemical processing for the salt clean-up, and the related economic as well as chemical engineering consequences. A new, innovative approach of balancing the throughput through salt processing based on a low number of separation process steps is developed. Next steps for the development of an economically viable salt clean-up process are identified.
