Transactions of the American Nuclear Society, Nov 1, 1985
Description/Abstract The motivation for this research is the belief that an on-line information s... more Description/Abstract The motivation for this research is the belief that an on-line information system is essential to enhance reliable operation of a commercial pressurized water reactor. It is further believed that the system should include a physically based analytical model ...
Transactions of the American Nuclear Society, 1981
To obtain a copy of this paper or presentation: note the name of the conference or event in the R... more To obtain a copy of this paper or presentation: note the name of the conference or event in the Resources Relation field. Other useful information can be found in the Availability, Publisher, Research Organization, Author (affiliation information) fields and/or Document ...
ABSTRACT Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 19... more ABSTRACT Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1984. Supervised by John E. Meyer. Includes bibliographical references (leaves 366-370).
ABSTRACT The broad effort of developing and assessing the two fluid model computer code THERMIT f... more ABSTRACT The broad effort of developing and assessing the two fluid model computer code THERMIT for light water reactor (LWR) subchannel analysis is described. The developmental effort required a reformulation of the coolant-to-fuel rod coupling so that THERMIT is now capable of traditional coolant-centered subchannel analysis. A model that accounts for mass, momentum and energy transport between mesh cells due to turbulent mixing for two-phase conditions has also been introduced. This model is the first such attempt in a two-fluid context. The liquid-vapor interfacial exchange terms in the two-fluid model have been modified for improved accuracy. A systematic evaluation of the exchange models has been performed. The mass and momentum exchange rates between the vapor and the liquid for pre-CHF conditions were evaluated by comparison to void fraction data in over 30 one-dimensional steady-state experiments reported in the open literature. The liquid-vapor energy exchange rate for post-CHF conditions was assessed using 15 steady-state, one-dimensional wall temperature measurements. The mixing model was tested against G.E. and Ispra BWR and PWR rod-bundle measurements. Comparisons with these measurements have shown the appropriateness of this model.
Description/Abstract THERMIT2, the most recent release of THERMIT, is intended for thermal-hydrau... more Description/Abstract THERMIT2, the most recent release of THERMIT, is intended for thermal-hydraulic analysis of both boiling and pressurized water reactor cores. It solves the three-dimensional, two-fluid equations describing the two-phase flow and heat transfer ...
A number of deficiencies in the original RCS and steam generator models on the Seabrook simulator... more A number of deficiencies in the original RCS and steam generator models on the Seabrook simulator were found to give unrealistic results under some off-normal and accident conditions. These deficiencies are attributed to the simplistic assumptions used in the original models, such as the homogeneous, equilibrium equations used in the pressurizer and steam generator models, and the single-phase flow model used in the ReS thermal-hydraulic model. To improve the fidelity of the simulator, efforts have been made to upgrade the ReS and steam generator models to include two-phase, nonequilibrium features. In the new ReS model, the following major assumptions are used to derive the finite difference form of the conservation equations: • A donor-cell differencing scheme is adopted to allow flow reversal. • A single pressure is used to evaluate properties. • A single mass flow rate is assumed in each loop. • Enthalpy is assumed to vary linearly within each control volume. • A homogeneous flow is assumed under two-phase conditions. The pressurizer is divided into a vapor region and a liquid region, each of which is represented by a set of mass and energy conservation equations. Interfacial mass and energy exchange mechanisms (condensation and flashing), thermal interactions between the vessel and fluids, and thermal nonequilibrium between the phases are included in the pressurizer model. The steam generator is divided into the vapor dome, riser, and downcomer regions. The assumptions applied are similar to those of the RCS and pressurizer models. A momentum model is incorporated to calculate the recirculation flow and simulate the-downcomer level shrink/swell phenomenon. The new RCS and steam generator models are validated by comparing the simulator calculations against sister plant data and FSAR vendor analysis. The results demonstrate that the new models give realistic and reliable calculations under off-normal and accident conditions.
A scaling analysis methodology was developed to determine the relative importance of the physical... more A scaling analysis methodology was developed to determine the relative importance of the physical phenomena in a postulated Large-Break Loss-of-Coolant-Accident (LBLOCA) scenario inside the U.S. EPR™ containment. Using a top-down scaling approach, a set of non-dimensional governing equations and the characteristic time ratios – referred to as Π-groups – were obtained for identifying the phenomena important to the system’s behavior. The resulting Π-groups were then ranked against a Phenomena Identification and Ranking Table (PIRT) generated by expert opinions. The PIRT provided both a validation of the importance ranking and an expansion of the PIRT to three phenomenological phases following a LBLOCA in the U.S. EPR™ plant. The classifications of the phases are: Blowdown, Pre Hot-Leg Injection, and Post Hot-Leg Injection. The Π-groups obtained from the non-dimensional governing equations were scaled against data from the Heissdampfreaktor (HDR) large-scale test facility to further va...
ABSTRACT Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 19... more ABSTRACT Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1984. Supervised by John E. Meyer. Includes bibliographical references (leaves 366-370).
A scaling analysis methodology was developed to determine the relative importance of the physical... more A scaling analysis methodology was developed to determine the relative importance of the physical phenomena in a postulated Large-Break Loss-of-Coolant-Accident (LBLOCA) scenario inside the U.S. EPR™ containment. Using a top-down scaling approach, a set of non-dimensional governing equations and the characteristic time ratios – referred to as Π-groups – were obtained for identifying the phenomena important to the system’s behavior. The resulting Π-groups were then ranked against a Phenomena Identification and Ranking Table (PIRT) generated by expert opinions. The PIRT provided both a validation of the importance ranking and an expansion of the PIRT to three phenomenological phases following a LBLOCA in the U.S. EPR™ plant. The classifications of the phases are: Blowdown, Pre Hot-Leg Injection, and Post Hot-Leg Injection. The Π-groups obtained from the non-dimensional governing equations were scaled against data from the Heissdampfreaktor (HDR) large-scale test facility to further validate the methodology and code applicability to simulate the U.S. EPR™ containment behavior following a LBLOCA. From this comparison, potential distortions of the test facility were identified. The impact of such distortions on the validity of comparing the test facility to the U.S. EPR™ prototype was evaluated. The scaling and distortion analysis results showed that the U.S. EPR™ containment scaled well against the HDR integral-effect test (IET) facility during both the blowdown and long-term cooling phases of a LBLOCA.
Description/Abstract The prediction of critical heat flux (CHF) in rod bundles has been studied w... more Description/Abstract The prediction of critical heat flux (CHF) in rod bundles has been studied with both subchannel and bundle-average methods. The correlations of Biasi, Bowring, CISE-4, and Barnett were considered. The General Electric 9-rod bundle CHF ...
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1984. Super... more Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1984. Supervised by John E. Meyer. Includes bibliographical references (leaves 366-370).
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1981. Supervi... more Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1981. Supervised by Mujid S. Kazimi. Includes bibliographical references.
Transactions of the American Nuclear Society, Nov 1, 1985
Description/Abstract The motivation for this research is the belief that an on-line information s... more Description/Abstract The motivation for this research is the belief that an on-line information system is essential to enhance reliable operation of a commercial pressurized water reactor. It is further believed that the system should include a physically based analytical model ...
Transactions of the American Nuclear Society, 1981
To obtain a copy of this paper or presentation: note the name of the conference or event in the R... more To obtain a copy of this paper or presentation: note the name of the conference or event in the Resources Relation field. Other useful information can be found in the Availability, Publisher, Research Organization, Author (affiliation information) fields and/or Document ...
ABSTRACT Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 19... more ABSTRACT Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1984. Supervised by John E. Meyer. Includes bibliographical references (leaves 366-370).
ABSTRACT The broad effort of developing and assessing the two fluid model computer code THERMIT f... more ABSTRACT The broad effort of developing and assessing the two fluid model computer code THERMIT for light water reactor (LWR) subchannel analysis is described. The developmental effort required a reformulation of the coolant-to-fuel rod coupling so that THERMIT is now capable of traditional coolant-centered subchannel analysis. A model that accounts for mass, momentum and energy transport between mesh cells due to turbulent mixing for two-phase conditions has also been introduced. This model is the first such attempt in a two-fluid context. The liquid-vapor interfacial exchange terms in the two-fluid model have been modified for improved accuracy. A systematic evaluation of the exchange models has been performed. The mass and momentum exchange rates between the vapor and the liquid for pre-CHF conditions were evaluated by comparison to void fraction data in over 30 one-dimensional steady-state experiments reported in the open literature. The liquid-vapor energy exchange rate for post-CHF conditions was assessed using 15 steady-state, one-dimensional wall temperature measurements. The mixing model was tested against G.E. and Ispra BWR and PWR rod-bundle measurements. Comparisons with these measurements have shown the appropriateness of this model.
Description/Abstract THERMIT2, the most recent release of THERMIT, is intended for thermal-hydrau... more Description/Abstract THERMIT2, the most recent release of THERMIT, is intended for thermal-hydraulic analysis of both boiling and pressurized water reactor cores. It solves the three-dimensional, two-fluid equations describing the two-phase flow and heat transfer ...
A number of deficiencies in the original RCS and steam generator models on the Seabrook simulator... more A number of deficiencies in the original RCS and steam generator models on the Seabrook simulator were found to give unrealistic results under some off-normal and accident conditions. These deficiencies are attributed to the simplistic assumptions used in the original models, such as the homogeneous, equilibrium equations used in the pressurizer and steam generator models, and the single-phase flow model used in the ReS thermal-hydraulic model. To improve the fidelity of the simulator, efforts have been made to upgrade the ReS and steam generator models to include two-phase, nonequilibrium features. In the new ReS model, the following major assumptions are used to derive the finite difference form of the conservation equations: • A donor-cell differencing scheme is adopted to allow flow reversal. • A single pressure is used to evaluate properties. • A single mass flow rate is assumed in each loop. • Enthalpy is assumed to vary linearly within each control volume. • A homogeneous flow is assumed under two-phase conditions. The pressurizer is divided into a vapor region and a liquid region, each of which is represented by a set of mass and energy conservation equations. Interfacial mass and energy exchange mechanisms (condensation and flashing), thermal interactions between the vessel and fluids, and thermal nonequilibrium between the phases are included in the pressurizer model. The steam generator is divided into the vapor dome, riser, and downcomer regions. The assumptions applied are similar to those of the RCS and pressurizer models. A momentum model is incorporated to calculate the recirculation flow and simulate the-downcomer level shrink/swell phenomenon. The new RCS and steam generator models are validated by comparing the simulator calculations against sister plant data and FSAR vendor analysis. The results demonstrate that the new models give realistic and reliable calculations under off-normal and accident conditions.
A scaling analysis methodology was developed to determine the relative importance of the physical... more A scaling analysis methodology was developed to determine the relative importance of the physical phenomena in a postulated Large-Break Loss-of-Coolant-Accident (LBLOCA) scenario inside the U.S. EPR™ containment. Using a top-down scaling approach, a set of non-dimensional governing equations and the characteristic time ratios – referred to as Π-groups – were obtained for identifying the phenomena important to the system’s behavior. The resulting Π-groups were then ranked against a Phenomena Identification and Ranking Table (PIRT) generated by expert opinions. The PIRT provided both a validation of the importance ranking and an expansion of the PIRT to three phenomenological phases following a LBLOCA in the U.S. EPR™ plant. The classifications of the phases are: Blowdown, Pre Hot-Leg Injection, and Post Hot-Leg Injection. The Π-groups obtained from the non-dimensional governing equations were scaled against data from the Heissdampfreaktor (HDR) large-scale test facility to further va...
ABSTRACT Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 19... more ABSTRACT Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1984. Supervised by John E. Meyer. Includes bibliographical references (leaves 366-370).
A scaling analysis methodology was developed to determine the relative importance of the physical... more A scaling analysis methodology was developed to determine the relative importance of the physical phenomena in a postulated Large-Break Loss-of-Coolant-Accident (LBLOCA) scenario inside the U.S. EPR™ containment. Using a top-down scaling approach, a set of non-dimensional governing equations and the characteristic time ratios – referred to as Π-groups – were obtained for identifying the phenomena important to the system’s behavior. The resulting Π-groups were then ranked against a Phenomena Identification and Ranking Table (PIRT) generated by expert opinions. The PIRT provided both a validation of the importance ranking and an expansion of the PIRT to three phenomenological phases following a LBLOCA in the U.S. EPR™ plant. The classifications of the phases are: Blowdown, Pre Hot-Leg Injection, and Post Hot-Leg Injection. The Π-groups obtained from the non-dimensional governing equations were scaled against data from the Heissdampfreaktor (HDR) large-scale test facility to further validate the methodology and code applicability to simulate the U.S. EPR™ containment behavior following a LBLOCA. From this comparison, potential distortions of the test facility were identified. The impact of such distortions on the validity of comparing the test facility to the U.S. EPR™ prototype was evaluated. The scaling and distortion analysis results showed that the U.S. EPR™ containment scaled well against the HDR integral-effect test (IET) facility during both the blowdown and long-term cooling phases of a LBLOCA.
Description/Abstract The prediction of critical heat flux (CHF) in rod bundles has been studied w... more Description/Abstract The prediction of critical heat flux (CHF) in rod bundles has been studied with both subchannel and bundle-average methods. The correlations of Biasi, Bowring, CISE-4, and Barnett were considered. The General Electric 9-rod bundle CHF ...
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1984. Super... more Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1984. Supervised by John E. Meyer. Includes bibliographical references (leaves 366-370).
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1981. Supervi... more Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1981. Supervised by Mujid S. Kazimi. Includes bibliographical references.
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