In this study,the effects of changing first wall materials and their thicknesses on a reactor were investigated to determine the displacement per atom(DPA)and gas production(helium and hydrogen)in the first wall,as we...In this study,the effects of changing first wall materials and their thicknesses on a reactor were investigated to determine the displacement per atom(DPA)and gas production(helium and hydrogen)in the first wall,as well as the tritium breeding ratio(TBR)in the coolant and tritium breeding zones.Therefore,the modeling of the magnetic fusion reactor was determined based on the blanket parameters of the International Thermonuclear Experimental Reactor(ITER).Stainless steel(SS 316 LNIG),Oxide Dispersion Strengthened Steel alloy(PM2000 ODS),and China low-activation martensitic steel(CLAM)were used as the first wall(FW)materials.Fluoride family molten salt materials(FLiBe,FLiNaBe,FLiPb)and lithium oxide(LiO_(2))were considered the coolant and tritium production material in the blanket,respectively.Neutron transport calculations were performed using the wellknown 3D code MCNP5 using the continuous-energy Monte Carlo method.The built-in continuous energy nuclear and atomic data libraries along with the Evaluated Nuclear Data file(ENDF)system(ENDF/B-V and ENDF/B-VI)were used.Additionally,the activity cross-section data library CLAW-IV was used to evaluate both the DPA values and gas production of the first wall(FW)materials.An interface computer program written in the FORTRAN 90 language to evaluate the MCNP5 outputs was developed for the fusion reactor blanket.The results indicated that the best TBR value was obtained for the use of the FLiPb coolant,whereas depending on the thickness,the first wall replacement period in terms of radiation damage to all materials was between 6 and 11 years.展开更多
Laser-induced breakdown spectroscopy (LIBS) is a powerful analytical tool for real- time diagnostics and detection of multiple elements deposited at the first wall of magnetically confined plasma ft^sion devices. Re...Laser-induced breakdown spectroscopy (LIBS) is a powerful analytical tool for real- time diagnostics and detection of multiple elements deposited at the first wall of magnetically confined plasma ft^sion devices. Recently, we have tested LIBS in our laboratory for application to in situ real-time diagnostics in the fusion device EAST. In this study, we applied polarization- resolved LIBS (PR-LIBS) to reduce the background continuum and enhance the resolution and sensitivity of LIBS. We used aluminium (A1) (as a substitute for Be) and the first wall materials tungsten (W) and molybdenum (Mo) to investigate polarized continuum emission and signal-to- background ratio (SBR). A Nd:YAG laser with first, second and third harmonics was used to produce plasma. The effects of the laser polarization plane, environmental pressure and polarizer detection angle were investigated. The spectra obtained without using a polarizer (i.e. LIBS) were compared with those obtained with a polarizer (PR-LIBS). Distribution of emission spectral intensity was observed to follow Malus' law with respect to variation in the angle of detection of the polarizer. The spectra obtained by PR-LIBS had a higher SBR and greater stability than those obtained by LIBS, thereby enhancing the reliability of LIBS for quantitative analyses. A comparison of A1, Mo and W showed that W exhibited a higher continuum with stronger polarization than the low-Z elements.展开更多
This paper explores the effect of a liquid lithium curtain on fusion reactor plasma, such curtain is utilized as the first wall for the engineering outline design of the Fusion Experimental Breeder (FEB-E). The rela...This paper explores the effect of a liquid lithium curtain on fusion reactor plasma, such curtain is utilized as the first wall for the engineering outline design of the Fusion Experimental Breeder (FEB-E). The relationships between the surface temperature of a liquid lithium curtain and the effective plasma charge, fuel dilution and fusion power production have been derived. Results indicate that under normal operation, the evaporation of liquid lithium does not seriously affect the effective plasma charge, but effects on fuel dilution and fusion power are more sensitive. As an example, it has investigated the relationships between the liquid lithium curtain flow velocity and the rise of surface temperature based on operation scenario II of the FEB-E design with reversed shear configuration and high power density. Results show that even if the liquid lithium curtain flow velocity is as low as 0.5 m/s, the effects of evaporation from the liquid lithium curtain on plasma are negligible. In the present design, the sputtering of liquid lithium curtain and the particle removal effects of the divertor are not yet considered in detail. Further studies are in progress, and in this work implication of lithium erosion and divertor physics on fusion reactor operation are discussed.展开更多
Tritium permeation through the first wall (FW) from the plasma into helium coolant is evaluated for a dual-functional lithium-lead test blanket module (DFLL-TBM). The effect of the surface conditions on the plasma...Tritium permeation through the first wall (FW) from the plasma into helium coolant is evaluated for a dual-functional lithium-lead test blanket module (DFLL-TBM). The effect of the surface conditions on the plasma facing and coolant sides, both temperature gradient and beryllium layer clad on the plasma facing side, as well as trapping in defects on the tritium permeation is considered. The results show that most of the tritium implanted in FW re-entered the plasma. The plasma-driven tritium permeation is very sensitive to the surface conditions on the plasma facing side. With a higher sticking coefficient on the plasma-facing side, the tritium permeation into helium coolant is significantly reduced. The tritium permeation is strongly reduced with a beryllium layer clad on the front side of FW. The plasma driven tritium permeation will not seriously impact the tritium safety of DFLL-TBM. Based on tritium safety, it is reasonable to clothe the beryllium layer on FW and keep the surface clean to reduce the plasma driven tritium permeation.展开更多
The Indian test blanket module(TBM) program in ITER is one of the major steps in the Indian fusion reactor program for carrying out the R&D activities in the critical areas like design of tritium breeding blankets ...The Indian test blanket module(TBM) program in ITER is one of the major steps in the Indian fusion reactor program for carrying out the R&D activities in the critical areas like design of tritium breeding blankets relevant to future Indian fusion devices(ITER relevant and DEMO).The Indian Lead–Lithium Cooled Ceramic Breeder(LLCB) blanket concept is one of the Indian DEMO relevant TBM,to be tested in ITER as a part of the TBM program.Helium-Cooled Ceramic Breeder(HCCB) is an alternative blanket concept that consists of lithium titanate(Li_2TiO_3) as ceramic breeder(CB) material in the form of packed pebble beds and beryllium as the neutron multiplier.Specifically,attentions are given to the optimization of first wall coolant channel design and size of breeder unit module considering coolant pressure and thermal loads for the proposed Indian HCCB blanket based on ITER relevant TBM and loading conditions.These analyses will help proceeding further in designing blankets for loads relevant to the future fusion device.展开更多
The finite element analysis and calculation were performed for the blanket first-wall made of SiC/SiC composite material for Advanced Steady-state Tokamak Reactor 2, A-SSTR2, which at present is conceptually designed ...The finite element analysis and calculation were performed for the blanket first-wall made of SiC/SiC composite material for Advanced Steady-state Tokamak Reactor 2, A-SSTR2, which at present is conceptually designed in Naka Fusion research establishment, JAERI. Comparison analysis and design window were analyzed using the finite element code ADINA 7.4. Through a 2D calculation for various geometrical configurations and sensitive material properties, a fundamental guideline for the first wall and blanket design are established with respect to maximum temperature, thermal and mechanical stress for many configurations. To satisfy hydrodynamic requirement, a4d4 (the dimension of coolant channel is 4 mm x 8 mm, and the distance between neighboring channels is 4 mm) was chosen as a design point for high thermal conductivity up to 50 W/m.K. In order to find a good solution for lower conductivity, more elaborate work should be done in the future. Nonetheless, the outline of design window for a specific structural material is very useful for the future A-SSTR2 first wall design.展开更多
The preparation, characterization, and test of the first wall materials designed to be used in the fusion reactor have remained challenging problems in the material science. This work uses the firstprinciples method a...The preparation, characterization, and test of the first wall materials designed to be used in the fusion reactor have remained challenging problems in the material science. This work uses the firstprinciples method as implemented in the CASTEP package to study the influ ences of the doped titanium carbide on the structural sta bility of the WTiC material. The calculated total energy and enthalpy have been used as criteria to judge the structural models built with consideration of symmetry. Our simulation indicates that the doped TiC tends to form its own domain up to the investigated nanoscale, which implies a possible phase separation. This result reveals the intrinsic reason for the composite nature of the WTiC material and provides an explanation for the experimen tally observed phase separation at the nanoscale. Our approach also sheds a light on explaining the enhancing effects of doped components on the durability, reliability, corrosion resistance, etc., in many special steels.展开更多
The first wall of the fusion reactor is a plasma-facing component and is a key link to maintain the integrity of structure during thermal shock induced by plasma disruptions. Be and W/Cu functionally graded materials ...The first wall of the fusion reactor is a plasma-facing component and is a key link to maintain the integrity of structure during thermal shock induced by plasma disruptions. Be and W/Cu functionally graded materials are two kinds of important plasma-facing materials(PFM) of first wall in fusion reactor currently. Previous researches seldom comparatively evaluated the normal servicing and heat shock resistance performance of first walls with those two kinds of PFMs. And also there lacks coupled thermal/mechanical analysis on the heat shock process in consideration of multiple thermal/mechanical phenomena, such as material melting, solidification, evaporation, etc., which is significant to further understand the heat shock damage mechanism of the first wall with different PFMs. With the aim of learning more detailed mechanical mechanism of thermal shock damage and then improving the thermal shock resistance performance of different first wall designs, the coupled thermal/mechanical response of two typical ITER-like first walls with PFM of Be and functionally graded W-Cu respectively under the heat shock of 1–2 GW/m^2 are computed by the finite element method. Special considerations of elastic-plastic deformation, material melting, and solidification are included in numerical models and methods. The mechanical response behaviors of different structures and materials under the normal servicing operation as well as plasma disruption conditions are analyzed and investigated comparatively. The results reveal that heat is mainly deposited on the PFM layer in the high energy shock pulse induced by plasma disruptions, resulting in complex thermal stress change as well as mechanical irreversible damage of thermal elastic and plastic expansion, contraction and yielding. Compared with the first wall with Be PFM, which mitigates the damages from heat shock at most only in the PFM layer with cost of whole PFM layer plastic yielding, the first wall with graded W-Cu PFM is demonstrated to be possessed both of higher heat shock resistance performance and normal servicing performance, provided its material gradient and cooling capacity are well optimized under practical loading conditions.展开更多
A 64-year-old female had noticed an 11 × 6 cm mass growing on her left first rib. We performed a resection of the first and second ribs and a reconstruction of the chest wall. A thoracotomy was performed at the a...A 64-year-old female had noticed an 11 × 6 cm mass growing on her left first rib. We performed a resection of the first and second ribs and a reconstruction of the chest wall. A thoracotomy was performed at the anterolateral second intercostal space. The second rib cartilage was divided at the left parasternum. Based on a transmanubrial osteomuscular sparing approach, the left-upper part of the sternum and the first rib cartilage were both cut at the left clavicular-sternum joint. The posterior parts of the two ribs involving the tumor were resected at the transverse process of the vertebral bone by tearing off the anterior, middle, and posterior scalene muscles, subclavicular artery and vein. The defect size of the thorax was 15 × 9 cm, which was reconstructed by covering with a polytetrafluoroethylene dual mesh (Dual mesh, Gore tex, 2 mm). The major pectoral muscle flap was used to cover the mesh. The postoperative pathological examination diagnosed a poorly differentiated fibrosarcoma. Eventually, she had palliative therapy for the postoperative metastatic chest wall. She died 14 months after the operation.展开更多
文摘In this study,the effects of changing first wall materials and their thicknesses on a reactor were investigated to determine the displacement per atom(DPA)and gas production(helium and hydrogen)in the first wall,as well as the tritium breeding ratio(TBR)in the coolant and tritium breeding zones.Therefore,the modeling of the magnetic fusion reactor was determined based on the blanket parameters of the International Thermonuclear Experimental Reactor(ITER).Stainless steel(SS 316 LNIG),Oxide Dispersion Strengthened Steel alloy(PM2000 ODS),and China low-activation martensitic steel(CLAM)were used as the first wall(FW)materials.Fluoride family molten salt materials(FLiBe,FLiNaBe,FLiPb)and lithium oxide(LiO_(2))were considered the coolant and tritium production material in the blanket,respectively.Neutron transport calculations were performed using the wellknown 3D code MCNP5 using the continuous-energy Monte Carlo method.The built-in continuous energy nuclear and atomic data libraries along with the Evaluated Nuclear Data file(ENDF)system(ENDF/B-V and ENDF/B-VI)were used.Additionally,the activity cross-section data library CLAW-IV was used to evaluate both the DPA values and gas production of the first wall(FW)materials.An interface computer program written in the FORTRAN 90 language to evaluate the MCNP5 outputs was developed for the fusion reactor blanket.The results indicated that the best TBR value was obtained for the use of the FLiPb coolant,whereas depending on the thickness,the first wall replacement period in terms of radiation damage to all materials was between 6 and 11 years.
基金supported by the National Magnetic Confinement Fusion Science Program of China(No.2013GB109005)National Natural Science Foundation of China(Nos.11175035,10875023)+1 种基金Chinesisch-Deutsches Forschungs Project(GZ768)the Fundamental Research Funds for the Central Universities(DUT12ZD(G)01)
文摘Laser-induced breakdown spectroscopy (LIBS) is a powerful analytical tool for real- time diagnostics and detection of multiple elements deposited at the first wall of magnetically confined plasma ft^sion devices. Recently, we have tested LIBS in our laboratory for application to in situ real-time diagnostics in the fusion device EAST. In this study, we applied polarization- resolved LIBS (PR-LIBS) to reduce the background continuum and enhance the resolution and sensitivity of LIBS. We used aluminium (A1) (as a substitute for Be) and the first wall materials tungsten (W) and molybdenum (Mo) to investigate polarized continuum emission and signal-to- background ratio (SBR). A Nd:YAG laser with first, second and third harmonics was used to produce plasma. The effects of the laser polarization plane, environmental pressure and polarizer detection angle were investigated. The spectra obtained without using a polarizer (i.e. LIBS) were compared with those obtained with a polarizer (PR-LIBS). Distribution of emission spectral intensity was observed to follow Malus' law with respect to variation in the angle of detection of the polarizer. The spectra obtained by PR-LIBS had a higher SBR and greater stability than those obtained by LIBS, thereby enhancing the reliability of LIBS for quantitative analyses. A comparison of A1, Mo and W showed that W exhibited a higher continuum with stronger polarization than the low-Z elements.
基金Project supported by the National Natural Science Foundation of China (Grant No 10085001), and in part the U.S. Department of Energy (Contract No W-31-109-ENG-38).
文摘This paper explores the effect of a liquid lithium curtain on fusion reactor plasma, such curtain is utilized as the first wall for the engineering outline design of the Fusion Experimental Breeder (FEB-E). The relationships between the surface temperature of a liquid lithium curtain and the effective plasma charge, fuel dilution and fusion power production have been derived. Results indicate that under normal operation, the evaporation of liquid lithium does not seriously affect the effective plasma charge, but effects on fuel dilution and fusion power are more sensitive. As an example, it has investigated the relationships between the liquid lithium curtain flow velocity and the rise of surface temperature based on operation scenario II of the FEB-E design with reversed shear configuration and high power density. Results show that even if the liquid lithium curtain flow velocity is as low as 0.5 m/s, the effects of evaporation from the liquid lithium curtain on plasma are negligible. In the present design, the sputtering of liquid lithium curtain and the particle removal effects of the divertor are not yet considered in detail. Further studies are in progress, and in this work implication of lithium erosion and divertor physics on fusion reactor operation are discussed.
基金supported by National Natural Science Foundation of China(Nos.10675123,10775135 and 50871108)the Knowledge Innovation Program of Chinese Academy of Sciences
文摘Tritium permeation through the first wall (FW) from the plasma into helium coolant is evaluated for a dual-functional lithium-lead test blanket module (DFLL-TBM). The effect of the surface conditions on the plasma facing and coolant sides, both temperature gradient and beryllium layer clad on the plasma facing side, as well as trapping in defects on the tritium permeation is considered. The results show that most of the tritium implanted in FW re-entered the plasma. The plasma-driven tritium permeation is very sensitive to the surface conditions on the plasma facing side. With a higher sticking coefficient on the plasma-facing side, the tritium permeation into helium coolant is significantly reduced. The tritium permeation is strongly reduced with a beryllium layer clad on the front side of FW. The plasma driven tritium permeation will not seriously impact the tritium safety of DFLL-TBM. Based on tritium safety, it is reasonable to clothe the beryllium layer on FW and keep the surface clean to reduce the plasma driven tritium permeation.
文摘The Indian test blanket module(TBM) program in ITER is one of the major steps in the Indian fusion reactor program for carrying out the R&D activities in the critical areas like design of tritium breeding blankets relevant to future Indian fusion devices(ITER relevant and DEMO).The Indian Lead–Lithium Cooled Ceramic Breeder(LLCB) blanket concept is one of the Indian DEMO relevant TBM,to be tested in ITER as a part of the TBM program.Helium-Cooled Ceramic Breeder(HCCB) is an alternative blanket concept that consists of lithium titanate(Li_2TiO_3) as ceramic breeder(CB) material in the form of packed pebble beds and beryllium as the neutron multiplier.Specifically,attentions are given to the optimization of first wall coolant channel design and size of breeder unit module considering coolant pressure and thermal loads for the proposed Indian HCCB blanket based on ITER relevant TBM and loading conditions.These analyses will help proceeding further in designing blankets for loads relevant to the future fusion device.
文摘The finite element analysis and calculation were performed for the blanket first-wall made of SiC/SiC composite material for Advanced Steady-state Tokamak Reactor 2, A-SSTR2, which at present is conceptually designed in Naka Fusion research establishment, JAERI. Comparison analysis and design window were analyzed using the finite element code ADINA 7.4. Through a 2D calculation for various geometrical configurations and sensitive material properties, a fundamental guideline for the first wall and blanket design are established with respect to maximum temperature, thermal and mechanical stress for many configurations. To satisfy hydrodynamic requirement, a4d4 (the dimension of coolant channel is 4 mm x 8 mm, and the distance between neighboring channels is 4 mm) was chosen as a design point for high thermal conductivity up to 50 W/m.K. In order to find a good solution for lower conductivity, more elaborate work should be done in the future. Nonetheless, the outline of design window for a specific structural material is very useful for the future A-SSTR2 first wall design.
基金finantially supported by the Science Foundation for International Cooperation of Sichuan Province (2014HH0016)the Fundamental Research Funds for the Central Universities (SWJTU2014: A0920502051113-10000)National Magnetic Confinement Fusion Science Program (2011GB112001)
文摘The preparation, characterization, and test of the first wall materials designed to be used in the fusion reactor have remained challenging problems in the material science. This work uses the firstprinciples method as implemented in the CASTEP package to study the influ ences of the doped titanium carbide on the structural sta bility of the WTiC material. The calculated total energy and enthalpy have been used as criteria to judge the structural models built with consideration of symmetry. Our simulation indicates that the doped TiC tends to form its own domain up to the investigated nanoscale, which implies a possible phase separation. This result reveals the intrinsic reason for the composite nature of the WTiC material and provides an explanation for the experimen tally observed phase separation at the nanoscale. Our approach also sheds a light on explaining the enhancing effects of doped components on the durability, reliability, corrosion resistance, etc., in many special steels.
基金supported by the National Magnetic Confinement Fusion Science Program of China(Grant Nos.2015GB121007&2013GB113004)
文摘The first wall of the fusion reactor is a plasma-facing component and is a key link to maintain the integrity of structure during thermal shock induced by plasma disruptions. Be and W/Cu functionally graded materials are two kinds of important plasma-facing materials(PFM) of first wall in fusion reactor currently. Previous researches seldom comparatively evaluated the normal servicing and heat shock resistance performance of first walls with those two kinds of PFMs. And also there lacks coupled thermal/mechanical analysis on the heat shock process in consideration of multiple thermal/mechanical phenomena, such as material melting, solidification, evaporation, etc., which is significant to further understand the heat shock damage mechanism of the first wall with different PFMs. With the aim of learning more detailed mechanical mechanism of thermal shock damage and then improving the thermal shock resistance performance of different first wall designs, the coupled thermal/mechanical response of two typical ITER-like first walls with PFM of Be and functionally graded W-Cu respectively under the heat shock of 1–2 GW/m^2 are computed by the finite element method. Special considerations of elastic-plastic deformation, material melting, and solidification are included in numerical models and methods. The mechanical response behaviors of different structures and materials under the normal servicing operation as well as plasma disruption conditions are analyzed and investigated comparatively. The results reveal that heat is mainly deposited on the PFM layer in the high energy shock pulse induced by plasma disruptions, resulting in complex thermal stress change as well as mechanical irreversible damage of thermal elastic and plastic expansion, contraction and yielding. Compared with the first wall with Be PFM, which mitigates the damages from heat shock at most only in the PFM layer with cost of whole PFM layer plastic yielding, the first wall with graded W-Cu PFM is demonstrated to be possessed both of higher heat shock resistance performance and normal servicing performance, provided its material gradient and cooling capacity are well optimized under practical loading conditions.
文摘A 64-year-old female had noticed an 11 × 6 cm mass growing on her left first rib. We performed a resection of the first and second ribs and a reconstruction of the chest wall. A thoracotomy was performed at the anterolateral second intercostal space. The second rib cartilage was divided at the left parasternum. Based on a transmanubrial osteomuscular sparing approach, the left-upper part of the sternum and the first rib cartilage were both cut at the left clavicular-sternum joint. The posterior parts of the two ribs involving the tumor were resected at the transverse process of the vertebral bone by tearing off the anterior, middle, and posterior scalene muscles, subclavicular artery and vein. The defect size of the thorax was 15 × 9 cm, which was reconstructed by covering with a polytetrafluoroethylene dual mesh (Dual mesh, Gore tex, 2 mm). The major pectoral muscle flap was used to cover the mesh. The postoperative pathological examination diagnosed a poorly differentiated fibrosarcoma. Eventually, she had palliative therapy for the postoperative metastatic chest wall. She died 14 months after the operation.