Xue-Nong Chen - Profile on Academia.edu (original) (raw)
Papers by Xue-Nong Chen
Energy Procedia, 2011
Fuels to be used in Accelerator Driven Systems dedicated to Minor Actinides transmutation can be ... more Fuels to be used in Accelerator Driven Systems dedicated to Minor Actinides transmutation can be described as highly innovative in comparison with those used in critical cores. Indeed, ADS fuels are not fertile, so as to improve the transmutation performance and they contain high volumetric concentrations (~50%) of minor actinides and plutonium compounds. This unusual fuel composition results in high gamma and neutron emissions during its fabrication, as well as degraded performances under irradiation. Ceramic-Ceramic and Ceramic Metallic composite fuels consisting of particles of (Pu,MA)O 2 phases dispersed in a magnesia or molybdenum matrix were investigated within the European Research programme for Transmutation, as driver fuels for a prospective 400MWth transmuter: the European Facility for Industrial Transmutation. Fuel performances and safety of preliminary core designs were evaluated to support the project. Out -of-pile as well as in-pile experiments were carried out to gain essential knowledge on properties and behaviour under irradiation of these types of fuel. This paper gives an overview of experimental results within the project.
Asymptotic radial fuel shuffling mode for accelerator driven transmuter
International Journal of Hydrogen Energy, 2016
Progress in Nuclear Energy, 2008
Asymptotic Solutions of Serial Radial Fuel Shuffling
Energies, 2015
This paper is a theoretical study of the mechanism of a radial standing wave, which can be applie... more This paper is a theoretical study of the mechanism of a radial standing wave, which can be applied in the so-called traveling wave reactor (TWR). One dimensional cylindrical core geometry is considered and the fuel is assumed to drift radially, which corresponds to a radial fuel shuffling scheme in practice. The key purpose of this study is to look for a standing wave solution under both conditions of inward and outward fuel drifting motions. A one-group diffusion equation coupled with burn-up equations is set up, as done in author's previous papers for axial drifting waves, where the burn-up solution were obtained as functions of neutron fluence, since the natural radioactive processes are neglected there. The uranium-plutonium (U-Pu) conversion cycle with pure 238 U as fresh fuel is considered under conditions of a typical sodium cooled fast reactor with UOX fuel loaded. The 1-D cylindrical coordinate problem is not analytically solvable like in the 1-D plane coordinate one. But standing wave solutions can be obtained here numerically for certain eigenvalues k eff . Two representative examples are shown for the inward and outward fuel drifting motions, respectively. Besides several other discussions, it can be concluded that the inward fuel drifting utilizes the burning/breeding process better than the outward one, where the former k eff is higher than the latter one.
Acta Mechanica Sinica
Based on the study on the Mach reflection of a solitary wave in , we continue to investigate effe... more Based on the study on the Mach reflection of a solitary wave in , we continue to investigate effects of the boundary layers on the bottom and the vertical side wall. By using matched asymptotic methods, the two-dimensional KdV equation is modified to account for effects of viscosity. Numerical simulation of the problem shows that the effects of side wall are important while the effects of the bottom can be neglected. The results including the side wall's effects agree satisfactorily with those of Melville's experiments. Finally, we establish the simplified concept of the side wall effectand conclude that it represents the physical reason for the discrepancy between the experiments and the previous calculations based on the inviscid fluid flow theory. KEY WORDS : solitary wave, Mach reflection, two-dimensional KdV equation ,viscous boundary layer, matched asymptotics
In the framework of the IAEA project on "Studies of Advanced Reactor Technology Options for Effec... more In the framework of the IAEA project on "Studies of Advanced Reactor Technology Options for Effective Incineration of Radioactive Waste," a series of benchmarks is performed to investigate the transient behaviors of various transmuters. One benchmark analysis concerns the transients in Accelerator Driven Transmuters (ADTs) using several types of dedicated fertile-free fuels, such as CERCER fuels with a ZrO 2 matrix or with an MgO matrix. For this benchmark, a mid-size 580MWth ADT with a large fraction of minor actinides (MAs) and Pb/Bi cooling has been proposed and investigated using the SIMMER-III code. As a first step, the relevant safety parameters have been determined, e.g., Doppler constants, coolant worth and cladding worth. Several transient classes have been analyzed, mostly focusing on reactivity-driven perturbations with time-scales in the ms and s range: unprotected transient overpower (UTOP), unprotected loss of flow (ULOF) and the unprotected blockage accident (UBA). In the area of UBAs a case has been simulated which leads to local pin failure and fuel redistribution in the flowing PB/Bi. For completeness, a beam trip (BT) and an unprotected transient over current (UTOC) have also been calculated.
The accelerator driven transmuter systems (ADTs) introduce three innovations, compared e.g. to cr... more The accelerator driven transmuter systems (ADTs) introduce three innovations, compared e.g. to critical sodium cooled fast spectrum burner reactors. A subcritical reactor driven by an external neutron source, the heavy metal coolant and the new dedicated fuels. All three innovations introduce new interrelated safety issues. Besides the dynamics of the subcritical system and the chosen Pb/Bi or Pb coolant, especially the innovative fuels will be the key focus in the safety investigations. The success of the transmutation idea strongly depends on the fuel issue and the successful development of these fuels represents a corner-stone of the ADT program. These so-called dedicated fuels should allow a maximization of incineration/transmutation rates. They are characterized by a high Minor Actinide (MA) content and by the lack of classical fertile materials as U238. European R&D for ADS fuels within the 5 th Framework Programme FUTURE has mainly concentrated on CERCER and CERMET oxide fuel forms. As matrix materials MgO and Mo are currently favored.. The safety behavior of these fuels is rather complex and significant R&D efforts are required. Strong interest focuses on the performance of these fuels under transient conditions and accident scenarios, also with the goal to identify any 'show stoppers'. New phenomena and safety issues have been can be identified and will need closer investigation. The performance of these fuels can be viewed firstly under the aspect of the fuel behavior itself and secondly on their impact on the overall reactor safety parameters. Generally, the high MA load leads to a deterioration of safety parameters which has to be balanced by the subcriticality and other safety measures. Analysis tools as the SIMMER-III/IV code are under development for adequately simulating the transient behavior of ADTs and to address the whole spectrum from normal operation to the behavior under low probability events which could lead to core melting and destruction. The code development comprises neutronic and thermal-hydraulic models up to new equations of states for the various materials. Based on these safety analyses the design and the performance of an ADT can be optimized and cliff-edge effect phenomena can be identified and eliminated.
Acta Mechanica Sinica
ABSTRACr: The diffraction of a solitary wave by a thin wedge with vertical walls is studied when ... more ABSTRACr: The diffraction of a solitary wave by a thin wedge with vertical walls is studied when the incident solitary wave is directed along the wedge axis. The method of multiple scales is extended to this problem and reduces the task to that of solving the two-dimensional KdV equation with proper boundary and initial conditions. The finite-difference numerical procedure is carried out with the fractional step algorithm in which difference schemes are all implicit. Except the maximum run-up at the wall, the results in this paper are found to corroborate the Melville's experiments not only qualitatively but also quantitatively. The maximum run-up of our results agrees well with Funakoshi's numerical one but it is considerably larger than that in Melville's experiment. An important reason for this discrepancy is believed to be the effect of viscous boundary layer on the vertical side wall.
Safety investigations for the lead/bismuth (Pb/Bi)-cooled experimental accelerator driven system ... more Safety investigations for the lead/bismuth (Pb/Bi)-cooled experimental accelerator driven system (XADS) were performed with the computational code SIMMER-III. The code has been extended so as to describe the ADS configuration with heavy-metal coolant, sub-critical core and strong external neutron source. As transient scenarios, unprotected loss of flow (ULOF), unprotected subassembly blockage and unprotected transient over-power (UTOP) were simulated. The calculation results showed that the current Pb/Bi-cooled XADS design proposed in the framework program of the European Union has remarkable resistance against severe scenarios.
In this paper the results of the investigation of the flow around the models of two ships in shal... more In this paper the results of the investigation of the flow around the models of two ships in shallow water without propeller, rudder and appendices are presented. The intention is -based on reliable experimental data -to compare computational results from different methods, obtained on different grids, and see how these methods perform. The experimental measurements comprise the velocity field at several stations, the free surface deformation, the hull pressure distribution and (not presented in this contribution) the bottom pressure. Three different computational methods were applied: A standard RANSEsolver on two different grids (one block-structured hexaedral, one unstructured tetraedral), a RANSEsolver using a fictitious compressibility and thus a flux-difference-splitting technique and a potential theoretic method devised for the transcritical regime (solitons!), where the hull is described merely by its cross-sectional area.
Nonlinear theory of asymmetric motion of a slender ship in a shallow channel
On ship at supercritical speeds
Ship wave making over a natural topography
Energy Procedia, 2011
Fuels to be used in Accelerator Driven Systems dedicated to Minor Actinides transmutation can be ... more Fuels to be used in Accelerator Driven Systems dedicated to Minor Actinides transmutation can be described as highly innovative in comparison with those used in critical cores. Indeed, ADS fuels are not fertile, so as to improve the transmutation performance and they contain high volumetric concentrations (~50%) of minor actinides and plutonium compounds. This unusual fuel composition results in high gamma and neutron emissions during its fabrication, as well as degraded performances under irradiation. Ceramic-Ceramic and Ceramic Metallic composite fuels consisting of particles of (Pu,MA)O 2 phases dispersed in a magnesia or molybdenum matrix were investigated within the European Research programme for Transmutation, as driver fuels for a prospective 400MWth transmuter: the European Facility for Industrial Transmutation. Fuel performances and safety of preliminary core designs were evaluated to support the project. Out -of-pile as well as in-pile experiments were carried out to gain essential knowledge on properties and behaviour under irradiation of these types of fuel. This paper gives an overview of experimental results within the project.
Asymptotic radial fuel shuffling mode for accelerator driven transmuter
International Journal of Hydrogen Energy, 2016
Progress in Nuclear Energy, 2008
Asymptotic Solutions of Serial Radial Fuel Shuffling
Energies, 2015
This paper is a theoretical study of the mechanism of a radial standing wave, which can be applie... more This paper is a theoretical study of the mechanism of a radial standing wave, which can be applied in the so-called traveling wave reactor (TWR). One dimensional cylindrical core geometry is considered and the fuel is assumed to drift radially, which corresponds to a radial fuel shuffling scheme in practice. The key purpose of this study is to look for a standing wave solution under both conditions of inward and outward fuel drifting motions. A one-group diffusion equation coupled with burn-up equations is set up, as done in author's previous papers for axial drifting waves, where the burn-up solution were obtained as functions of neutron fluence, since the natural radioactive processes are neglected there. The uranium-plutonium (U-Pu) conversion cycle with pure 238 U as fresh fuel is considered under conditions of a typical sodium cooled fast reactor with UOX fuel loaded. The 1-D cylindrical coordinate problem is not analytically solvable like in the 1-D plane coordinate one. But standing wave solutions can be obtained here numerically for certain eigenvalues k eff . Two representative examples are shown for the inward and outward fuel drifting motions, respectively. Besides several other discussions, it can be concluded that the inward fuel drifting utilizes the burning/breeding process better than the outward one, where the former k eff is higher than the latter one.
Acta Mechanica Sinica
Based on the study on the Mach reflection of a solitary wave in , we continue to investigate effe... more Based on the study on the Mach reflection of a solitary wave in , we continue to investigate effects of the boundary layers on the bottom and the vertical side wall. By using matched asymptotic methods, the two-dimensional KdV equation is modified to account for effects of viscosity. Numerical simulation of the problem shows that the effects of side wall are important while the effects of the bottom can be neglected. The results including the side wall's effects agree satisfactorily with those of Melville's experiments. Finally, we establish the simplified concept of the side wall effectand conclude that it represents the physical reason for the discrepancy between the experiments and the previous calculations based on the inviscid fluid flow theory. KEY WORDS : solitary wave, Mach reflection, two-dimensional KdV equation ,viscous boundary layer, matched asymptotics
In the framework of the IAEA project on "Studies of Advanced Reactor Technology Options for Effec... more In the framework of the IAEA project on "Studies of Advanced Reactor Technology Options for Effective Incineration of Radioactive Waste," a series of benchmarks is performed to investigate the transient behaviors of various transmuters. One benchmark analysis concerns the transients in Accelerator Driven Transmuters (ADTs) using several types of dedicated fertile-free fuels, such as CERCER fuels with a ZrO 2 matrix or with an MgO matrix. For this benchmark, a mid-size 580MWth ADT with a large fraction of minor actinides (MAs) and Pb/Bi cooling has been proposed and investigated using the SIMMER-III code. As a first step, the relevant safety parameters have been determined, e.g., Doppler constants, coolant worth and cladding worth. Several transient classes have been analyzed, mostly focusing on reactivity-driven perturbations with time-scales in the ms and s range: unprotected transient overpower (UTOP), unprotected loss of flow (ULOF) and the unprotected blockage accident (UBA). In the area of UBAs a case has been simulated which leads to local pin failure and fuel redistribution in the flowing PB/Bi. For completeness, a beam trip (BT) and an unprotected transient over current (UTOC) have also been calculated.
The accelerator driven transmuter systems (ADTs) introduce three innovations, compared e.g. to cr... more The accelerator driven transmuter systems (ADTs) introduce three innovations, compared e.g. to critical sodium cooled fast spectrum burner reactors. A subcritical reactor driven by an external neutron source, the heavy metal coolant and the new dedicated fuels. All three innovations introduce new interrelated safety issues. Besides the dynamics of the subcritical system and the chosen Pb/Bi or Pb coolant, especially the innovative fuels will be the key focus in the safety investigations. The success of the transmutation idea strongly depends on the fuel issue and the successful development of these fuels represents a corner-stone of the ADT program. These so-called dedicated fuels should allow a maximization of incineration/transmutation rates. They are characterized by a high Minor Actinide (MA) content and by the lack of classical fertile materials as U238. European R&D for ADS fuels within the 5 th Framework Programme FUTURE has mainly concentrated on CERCER and CERMET oxide fuel forms. As matrix materials MgO and Mo are currently favored.. The safety behavior of these fuels is rather complex and significant R&D efforts are required. Strong interest focuses on the performance of these fuels under transient conditions and accident scenarios, also with the goal to identify any 'show stoppers'. New phenomena and safety issues have been can be identified and will need closer investigation. The performance of these fuels can be viewed firstly under the aspect of the fuel behavior itself and secondly on their impact on the overall reactor safety parameters. Generally, the high MA load leads to a deterioration of safety parameters which has to be balanced by the subcriticality and other safety measures. Analysis tools as the SIMMER-III/IV code are under development for adequately simulating the transient behavior of ADTs and to address the whole spectrum from normal operation to the behavior under low probability events which could lead to core melting and destruction. The code development comprises neutronic and thermal-hydraulic models up to new equations of states for the various materials. Based on these safety analyses the design and the performance of an ADT can be optimized and cliff-edge effect phenomena can be identified and eliminated.
Acta Mechanica Sinica
ABSTRACr: The diffraction of a solitary wave by a thin wedge with vertical walls is studied when ... more ABSTRACr: The diffraction of a solitary wave by a thin wedge with vertical walls is studied when the incident solitary wave is directed along the wedge axis. The method of multiple scales is extended to this problem and reduces the task to that of solving the two-dimensional KdV equation with proper boundary and initial conditions. The finite-difference numerical procedure is carried out with the fractional step algorithm in which difference schemes are all implicit. Except the maximum run-up at the wall, the results in this paper are found to corroborate the Melville's experiments not only qualitatively but also quantitatively. The maximum run-up of our results agrees well with Funakoshi's numerical one but it is considerably larger than that in Melville's experiment. An important reason for this discrepancy is believed to be the effect of viscous boundary layer on the vertical side wall.
Safety investigations for the lead/bismuth (Pb/Bi)-cooled experimental accelerator driven system ... more Safety investigations for the lead/bismuth (Pb/Bi)-cooled experimental accelerator driven system (XADS) were performed with the computational code SIMMER-III. The code has been extended so as to describe the ADS configuration with heavy-metal coolant, sub-critical core and strong external neutron source. As transient scenarios, unprotected loss of flow (ULOF), unprotected subassembly blockage and unprotected transient over-power (UTOP) were simulated. The calculation results showed that the current Pb/Bi-cooled XADS design proposed in the framework program of the European Union has remarkable resistance against severe scenarios.
In this paper the results of the investigation of the flow around the models of two ships in shal... more In this paper the results of the investigation of the flow around the models of two ships in shallow water without propeller, rudder and appendices are presented. The intention is -based on reliable experimental data -to compare computational results from different methods, obtained on different grids, and see how these methods perform. The experimental measurements comprise the velocity field at several stations, the free surface deformation, the hull pressure distribution and (not presented in this contribution) the bottom pressure. Three different computational methods were applied: A standard RANSEsolver on two different grids (one block-structured hexaedral, one unstructured tetraedral), a RANSEsolver using a fictitious compressibility and thus a flux-difference-splitting technique and a potential theoretic method devised for the transcritical regime (solitons!), where the hull is described merely by its cross-sectional area.
Nonlinear theory of asymmetric motion of a slender ship in a shallow channel
On ship at supercritical speeds
Ship wave making over a natural topography