The Experts below are selected from a list of 429 Experts worldwide ranked by ideXlab platform
Driscoll M. J. - One of the best experts on this subject based on the ideXlab platform.
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Conceptual Design of a Large, Passive Pressure-Tube Light Water Reactor
Massachusetts Institute of Technology. Center for Advanced Nuclear Energy Systems. Advanced Nuclear Power Program, 1994Co-Authors: Hejzlar P., Todreas N. E., Driscoll M. J.Abstract:A design for a large, passive, light water reactor has been developed. The proposed concept is a pressure tube reactor of similar design to CANDU reactors, but differing in three key aspects. First, a solid SiC-coated graphite fuel matrix is used in place of pin-rod bundles to enable the dissipation of decay heat from the fuel in the absence of primary coolant. Second, the heavy water coolant in the pressure tubes is replaced by light water, which serves also as the moderator. Finally, the calandria is connected to a light water heat sink. The cover gas keeps the light water out of the calandria during normal operation, which during loss of coolant or loss of heat sink accidents it allows passive calandria flooding. Calandria flooding also provides redundant and diverse reactor shutdown. The entire primary system is enclosed in a robust, free standing cylindrical steel containment cooled solely by buoyancy-induced air flow, and surrounded by a concrete shield building. It is show that the proposed reactor can survive loss of coolant accidents without scram and without replenishing primary coolant inventory, while the safe temperature limits on the fuel and pressure tube are not exceeded. It can cope with station blackout and anticipated transients without scram — the major traditional contributors to core damage frequency — without sustaining core damage. The fuel elements can operate under post-CHF conditions even at full power, without exceeding fuel design limits. The heterogeneous arrangement of the fuel and moderator ensures a negative void coefficient under all circumstances. Although light water is used as both coolant and moderator, the reactor exhibits high Neutron thermalization and a large Prompt Neutron Lifetime, similar to D[subscript 2]O moderated cores. Moreover, the extremely large Neutron migration length results in a strongly coupled core with a flat thermal flux profile, and inherent stability against xenon spatial oscillations.United States. Dept. of Energ
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Conceptual Design of a Large, Passive Pressure-Tube Light Water Reactor
Massachusetts Institute of Technology. Center for Advanced Nuclear Energy Systems. Advanced Nuclear Power Program, 1994Co-Authors: Hejzlar P., Todreas N. E., Driscoll M. J.Abstract:A design for a large, passive, light water reactor has been developed. The proposed concept is a pressure tube reactor of similar design to CANDU reactors, but differing in three key aspects. First, a solid Sic-coated graphite fuel matrix is used in place of pin-rod bundles to enable the dissipation of decay heat from the fuel in the absence of primary coolant. Second, the heavy water coolant in the pressure tubes is replaced by light water, which serves also as the moderator. Finally, the calandria tank, surrounded by a graphite reflector, contains a low pressure gas instead of heavy water moderator, and the normally-voided calandria is connected to a light water heat sink. The cover gas keeps the light water out of the calandria during normal operation, while during loss of coolant or loss of heat sink accidents it allows passive calandria flooding. Calandria flooding also provides redundant and diverse reactor shutdown. The entire primary system is enclosed in a robust, free standing cylindrical steel containment cooled solely by buoyancy-induced air flow, and surrounded by a concrete shield building. It is shown that the proposed reactor can survive loss of coolant accidents without scram and without replenishing primary coolant inventory, while the safe temperature limits on the fuel and pressure tube are not exceeded. It can cope with station blackout and anticipated transients without scram - the major traditional contributors to core damage frequency - without sustaining core damage. The fuel elements can operate under post-CHF conditions even at full power, without exceeding fuel design limits. The heterogeneous arrangement of the fuel and moderator ensures a negative void coefficient under all circumstances. Although light water is used as both coolant and moderator, the reactor exhibits high Neutron thermalization and a large Prompt Neutron Lifetime, similar to DgO moderated cores. Moreover, the extremely large Neutron migration length results in a strongly coupled core with a flat thermal flux profile, and inherent stability against xenon spatial oscillations.United States. Dept. of Energ
Samad Khakshournia - One of the best experts on this subject based on the ideXlab platform.
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calculation of six group importance weighted delayed Neutron fractions and Prompt Neutron Lifetime of mtr research reactors based on monte carlo method
Progress in Nuclear Energy, 2016Co-Authors: Mohammad Arkani, M Hassanzadeh, Samad KhakshourniaAbstract:Abstract The accurate estimation of effective delayed Neutron fraction and Prompt Neutron Lifetime are of major concerns in safety analysis of nuclear reactors. In this paper, Tehran Research Reactor (TRR) is taken as a case study of MTR research reactors and kinetic parameters of the facility are estimated utilizing Monte Carlo Neutron Importance Calculation (MCNIC) method. The results are compared with 1 / υ poisoning, k-ratio, perturbation, and zero power reactor noise (ZPRN) methods. Taking perturbation results as reference information, the percent error in effective delayed Neutron fraction calculated by MCNIC, k-ratio, and ZPRN methods are −3.7, −6.8, and 1.7 respectively. These results for l p parameter calculated by MCNIC, 1/υ poisoning, and ZPRN methods are 2.9, 5.7, and 6.4 respectively. A good agreement is seen among different methods of estimation. Note that error originated from cross section library is a different source of error which is also discussed in the text. As MCNIC method considers the problem in a more realistic manner, considering Neutron importance in calculations, this method is more reliable than the other methods. A quantitative and qualitative discussion is given in the paper to indicate the advantages and disadvantages of each method for the case study in TRR.
Neil E. Todreas - One of the best experts on this subject based on the ideXlab platform.
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large passive pressure tube light water reactor with voided calandria
Nuclear Technology, 1996Co-Authors: Pavel Hejzlar, Neil E. Todreas, Michael J. DriscollAbstract:A reactor concept has been developed that can survive loss-of-coolant accidents (LOCAs) without scram and without replenishing primary coolant inventory while maintaining safe temperature limits on the fuel and pressure tube. The proposed concept is a pressure tube reactor of similar design to Canada deuterium uranium reactors but differing in three key aspects. First, a solid silicon carbide-coated graphite fuel matrix is used in place of fuel pin bundles to enable the dissipation of decay heat from the fuel in the absence of primary coolant. Second, the heavy water coolant in the pressure tubes is replaced by light water, which also serves as the moderator. Finally, the calandria tank, surrounded by a graphite reflector, contains a low-pressure gas instead of heavy water moderator, and this normally voided calandria is connected to a light water heat sink. The cover gas displaces the light water from the calandria during normal operation while during a LOCA or loss of heat sink accident, it allows passive calandria flooding. Calandria flooding also provides redundant and diverse reactor shutdown. The fuel elements can operate under post-critical-heat-flux conditions even at full power without exceeding fuel design limits. The heterogeneous arrangement of the fuel and moderator ensures amore » negative void coefficient under all circumstances. Although light water is used as both coolant and moderator, the reactor exhibits a high degree of Neutron thermalization and a large Prompt Neutron Lifetime, similar to D{sub 2}O-moderated cores. Moreover, the extremely large Neutron migration length results in a strongly coupled core with a flat thermal flux profile and inherent stability against xenon spatial oscillations.« less
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physics characteristics of a large passive pressure tube light water reactor with voided calandria
Nuclear Science and Engineering, 1995Co-Authors: Pavel Hejzlar, Michael J. Driscoll, Neil E. TodreasAbstract:A light water cooled and moderated pressure tube reactor concept has been developed that can survive loss-of-coolant accidents (LOCAs) without scram and without replenishing primary coolant inventory, while maintaining safe temperature limits on the fuel and pressure tube. The reactor employs a solid SiC-coated graphite fuel matrix in the pressure tubes and a calandria tank containing a low-pressure gas, surrounded by a graphite reflector. This normally voided calandria is connected to a light water heat sink. The cover gas displaces light water from the calandria during normal operation, while during LOCAs it allows passive calandria flooding. It is shown that such a system, with high void fraction in the core region, exhibits a high degree of Neutron thermalization and a large Prompt Neutron Lifetime, similar to D{sub 2}O moderated cores, although light water is used as both coolant and moderator. Moreover, the extremely large Neutron migration length results in a strongly coupled core with a flat thermal flux profile and inherent stability against xenon spatial oscillations. The heterogeneous arrangement of the fuel and moderator ensures a negative void coefficient under all circumstances. Flooding of the calandria space with light water results in redundant reactor shutdown. Use of particle fuel allowsmore » attainment of high burnups.« less
Michael J. Driscoll - One of the best experts on this subject based on the ideXlab platform.
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large passive pressure tube light water reactor with voided calandria
Nuclear Technology, 1996Co-Authors: Pavel Hejzlar, Neil E. Todreas, Michael J. DriscollAbstract:A reactor concept has been developed that can survive loss-of-coolant accidents (LOCAs) without scram and without replenishing primary coolant inventory while maintaining safe temperature limits on the fuel and pressure tube. The proposed concept is a pressure tube reactor of similar design to Canada deuterium uranium reactors but differing in three key aspects. First, a solid silicon carbide-coated graphite fuel matrix is used in place of fuel pin bundles to enable the dissipation of decay heat from the fuel in the absence of primary coolant. Second, the heavy water coolant in the pressure tubes is replaced by light water, which also serves as the moderator. Finally, the calandria tank, surrounded by a graphite reflector, contains a low-pressure gas instead of heavy water moderator, and this normally voided calandria is connected to a light water heat sink. The cover gas displaces the light water from the calandria during normal operation while during a LOCA or loss of heat sink accident, it allows passive calandria flooding. Calandria flooding also provides redundant and diverse reactor shutdown. The fuel elements can operate under post-critical-heat-flux conditions even at full power without exceeding fuel design limits. The heterogeneous arrangement of the fuel and moderator ensures amore » negative void coefficient under all circumstances. Although light water is used as both coolant and moderator, the reactor exhibits a high degree of Neutron thermalization and a large Prompt Neutron Lifetime, similar to D{sub 2}O-moderated cores. Moreover, the extremely large Neutron migration length results in a strongly coupled core with a flat thermal flux profile and inherent stability against xenon spatial oscillations.« less
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physics characteristics of a large passive pressure tube light water reactor with voided calandria
Nuclear Science and Engineering, 1995Co-Authors: Pavel Hejzlar, Michael J. Driscoll, Neil E. TodreasAbstract:A light water cooled and moderated pressure tube reactor concept has been developed that can survive loss-of-coolant accidents (LOCAs) without scram and without replenishing primary coolant inventory, while maintaining safe temperature limits on the fuel and pressure tube. The reactor employs a solid SiC-coated graphite fuel matrix in the pressure tubes and a calandria tank containing a low-pressure gas, surrounded by a graphite reflector. This normally voided calandria is connected to a light water heat sink. The cover gas displaces light water from the calandria during normal operation, while during LOCAs it allows passive calandria flooding. It is shown that such a system, with high void fraction in the core region, exhibits a high degree of Neutron thermalization and a large Prompt Neutron Lifetime, similar to D{sub 2}O moderated cores, although light water is used as both coolant and moderator. Moreover, the extremely large Neutron migration length results in a strongly coupled core with a flat thermal flux profile and inherent stability against xenon spatial oscillations. The heterogeneous arrangement of the fuel and moderator ensures a negative void coefficient under all circumstances. Flooding of the calandria space with light water results in redundant reactor shutdown. Use of particle fuel allowsmore » attainment of high burnups.« less
Mohammad Arkani - One of the best experts on this subject based on the ideXlab platform.
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Diagnostic methods applied to Esfahan light water subcritical reactor (ELWSCR)
'Elsevier BV', 2021Co-Authors: Mohammad ArkaniAbstract:In this work, Esfahan light water subcritical reactor (ELWSCR) is analysed using experimental and theoretical diagnostic methods. Important Neutronic parameters of the system such as Prompt Neutron Lifetime, delayed Neutron fraction, Prompt Neutron decay constant, negative reactivity of the core, fuel and moderator temperature coefficient of reactivity, and overall and local void coefficient of reactivity are estimated. Also, Neutron flux distribution, reflector saving, water level effect, and lattice pitch of the core including operating point of the facility are studied in details. Theoretical results are calculated by MCNPX and measurements are performed utilizing zero power reactor noise method. Detailed descriptions of the results are explained in the text
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calculation of six group importance weighted delayed Neutron fractions and Prompt Neutron Lifetime of mtr research reactors based on monte carlo method
Progress in Nuclear Energy, 2016Co-Authors: Mohammad Arkani, M Hassanzadeh, Samad KhakshourniaAbstract:Abstract The accurate estimation of effective delayed Neutron fraction and Prompt Neutron Lifetime are of major concerns in safety analysis of nuclear reactors. In this paper, Tehran Research Reactor (TRR) is taken as a case study of MTR research reactors and kinetic parameters of the facility are estimated utilizing Monte Carlo Neutron Importance Calculation (MCNIC) method. The results are compared with 1 / υ poisoning, k-ratio, perturbation, and zero power reactor noise (ZPRN) methods. Taking perturbation results as reference information, the percent error in effective delayed Neutron fraction calculated by MCNIC, k-ratio, and ZPRN methods are −3.7, −6.8, and 1.7 respectively. These results for l p parameter calculated by MCNIC, 1/υ poisoning, and ZPRN methods are 2.9, 5.7, and 6.4 respectively. A good agreement is seen among different methods of estimation. Note that error originated from cross section library is a different source of error which is also discussed in the text. As MCNIC method considers the problem in a more realistic manner, considering Neutron importance in calculations, this method is more reliable than the other methods. A quantitative and qualitative discussion is given in the paper to indicate the advantages and disadvantages of each method for the case study in TRR.
