Neutron flux monitor (NFM) as an important diagnostic sub-system in ITER (international thermonuclear experimental reactor) provides a global neutron source intensity, fusion power and neutron flux in real time. T...Neutron flux monitor (NFM) as an important diagnostic sub-system in ITER (international thermonuclear experimental reactor) provides a global neutron source intensity, fusion power and neutron flux in real time. Three types of neutron flux monitor assemblies with different sensitivities and shielding materials have been designed. Through MCNP (Mante-Carlo neutral particle transport code) calculations, this extended system of NFM can detect the neutron flux in a range of 10^4 n/(cm^2.s) to 10^14 n/(cm^2.s). It is capable of providing accurate neutron yield measurements for all operational modes encountered in the ITER experiments including the in-situ calibration. Combining both the counting mode and Campbelling (MSV; Mean Square Voltage) mode in the signal processing units, the requirement of the dynamic range (107) for these NFMs and time resolution (1 ms) can be met. Based on a uncertainty analysis, the estimated absolute measurement accuracies of the total fusion neutron yield can reach the required 10% level in both the early stage of the DD-phase and the DD-phase, the absolute measurement accuracy full power DT operation mode. In the advanced would be better than 20%.展开更多
The prototype neutron flux monitor consists of a high purity 235U fission chamber detector and a 'blank' detector, which is a fissile material free detector with the same dimension as the fission chamber detec...The prototype neutron flux monitor consists of a high purity 235U fission chamber detector and a 'blank' detector, which is a fissile material free detector with the same dimension as the fission chamber detector to identify noise issues such as noise coming from gamma rays. The main parameters of the fission chamber assembly that have been measured in the laboratory are confirmed to approach the technological level of the International Thermonuclear Experimental Reactor (ITER) in the near future. This prototype neutron flux monitor will be further developed to become a neutron flux monitor suitable for the operation phase of D-D fusion on the ITER.展开更多
The core snubber, as a passive protection device, can suppress arc current and absorb stored energy in stray capacitance during the electrical breakdown in accelerating electrodes of ITER NBI. In order to design the c...The core snubber, as a passive protection device, can suppress arc current and absorb stored energy in stray capacitance during the electrical breakdown in accelerating electrodes of ITER NBI. In order to design the core snubber of ITER, the control parameters of the arc peak current have been firstly analyzed by the Fink-Baker-Owren (FBO) method, which are used for designing the DIIID 100 kV snubber. The B-H curve can be derived from the measured voltage and current waveforms, and the hysteresis loss of the core snubber can be derived using the revised parallelogram method. The core snubber can be a simplified representation as an equivalent parallel resistance and inductance, which has been neglected by the FBO method. A simulation code including the parallel equivalent resistance and inductance has been set up. The simulation and experiments result in dramatically large arc shorting currents due to the parallel inductance effect. The case shows that the core snubber utilizing the FBO method gives more compact design.展开更多
In this study, a full-scale internal circulation(IC) reactor coupled with an external circulation system was developed to treat high-strength leachate from a municipal solid waste(MSW)incineration plant, in which ...In this study, a full-scale internal circulation(IC) reactor coupled with an external circulation system was developed to treat high-strength leachate from a municipal solid waste(MSW)incineration plant, in which anaerobic sludge granulation was intensively investigated. Results showed that the IC reactor achieved excellent treatment performance under high organic loading rates(OLR) of 21.06–25.16 kg chemical oxygen demand(COD)/(m3? day). The COD removal efficiency and biogas yield respectively reached 89.4%–93.4% and 0.42–0.50 m3/kg COD.The formation of extracellular polymeric substances(EPS) was closely associated with sludge granulation. Protein was the dominant component in sludge EPS, and its content was remarkably increased from 21.6 to 99.7 mg/g Volatile Suspended Solid(VSS) during the reactor operation. The sludge Zeta potential and hydrophobicity positively correlated with the protein/polysaccharide ratio in EPS, and they were respectively increased from-26.2 m V and 30.35% to-10.6 m V and 78.67%, which was beneficial to microbial aggregation. Three-dimensional fluorescence spectroscopy(3 D-EEM) and Fourier transform infrared spectroscopy(FT-IR)analysis further indicated the importance of protein-like EPS substances in the sludge granulation. Moreover, it was also found that the secondary structures of EPS proteins varied during the reactor operation.展开更多
The degradation of atrazine (ATZ),sulfamethoxazole (SMX) and metoprolol (MET) in flowthrough VUV/UV/H2O2reactors was investigated with a focus on the effects of H2O2dosage and reactor internal diameter (ID).Results sh...The degradation of atrazine (ATZ),sulfamethoxazole (SMX) and metoprolol (MET) in flowthrough VUV/UV/H2O2reactors was investigated with a focus on the effects of H2O2dosage and reactor internal diameter (ID).Results showed that the micropollutants were degraded efficiently in the flow-through VUV/UV/H2O2reactors following the pseudo first-order kinetics (R2>0.92).However,the steady-state assumption (SSA) kinetic model being vital in batch reactors was found invalid in flow-through reactors where fluid mixing was less sufficient.With the increase of H2O2dosage,the ATZ removal efficiency remained almost constant while the SMX and MET removal was enhanced to different extents,which could be explained by the different reactivities of the pollutants towards HO·.A larger reactor ID resulted in lower degradation rate constants for all the three pollutants on account of the lower average fluence rate,but the change in energy efficiency was much more complicated.In reality,the electrical energy per order (EEO) of the investigated VUV/UV/H2O2treatments ranged between 0.14–0.20,0.07–0.14 and 0.09–0.26 k Wh/m3/order for ATZ,SMX and MET,respectively,with the lowest EEOfor each pollutant obtained under varied H2O2dosages and reactor IDs.This study has demonstrated the efficiency of VUV/UV/H2O2process for micropollutant removal and the inadequacy of the SSA model in flow-through reactors,and elaborated the influential mechanisms of H2O2dosage and reactor ID on the reactor performances.展开更多
基金National Natural Science Foundation of China(Nos.10175021,10675124)
文摘Neutron flux monitor (NFM) as an important diagnostic sub-system in ITER (international thermonuclear experimental reactor) provides a global neutron source intensity, fusion power and neutron flux in real time. Three types of neutron flux monitor assemblies with different sensitivities and shielding materials have been designed. Through MCNP (Mante-Carlo neutral particle transport code) calculations, this extended system of NFM can detect the neutron flux in a range of 10^4 n/(cm^2.s) to 10^14 n/(cm^2.s). It is capable of providing accurate neutron yield measurements for all operational modes encountered in the ITER experiments including the in-situ calibration. Combining both the counting mode and Campbelling (MSV; Mean Square Voltage) mode in the signal processing units, the requirement of the dynamic range (107) for these NFMs and time resolution (1 ms) can be met. Based on a uncertainty analysis, the estimated absolute measurement accuracies of the total fusion neutron yield can reach the required 10% level in both the early stage of the DD-phase and the DD-phase, the absolute measurement accuracy full power DT operation mode. In the advanced would be better than 20%.
基金The project supported by the National Natural Science Foundation of China (No.10175021)the Retraining Foundation of the Southwestern Institute of Physics for Talented Personnel
文摘The prototype neutron flux monitor consists of a high purity 235U fission chamber detector and a 'blank' detector, which is a fissile material free detector with the same dimension as the fission chamber detector to identify noise issues such as noise coming from gamma rays. The main parameters of the fission chamber assembly that have been measured in the laboratory are confirmed to approach the technological level of the International Thermonuclear Experimental Reactor (ITER) in the near future. This prototype neutron flux monitor will be further developed to become a neutron flux monitor suitable for the operation phase of D-D fusion on the ITER.
基金supported by National Program on Key Basic Research Project of ITER Core Snubber in China (973 Program) (No.2010GB108003)
文摘The core snubber, as a passive protection device, can suppress arc current and absorb stored energy in stray capacitance during the electrical breakdown in accelerating electrodes of ITER NBI. In order to design the core snubber of ITER, the control parameters of the arc peak current have been firstly analyzed by the Fink-Baker-Owren (FBO) method, which are used for designing the DIIID 100 kV snubber. The B-H curve can be derived from the measured voltage and current waveforms, and the hysteresis loss of the core snubber can be derived using the revised parallelogram method. The core snubber can be a simplified representation as an equivalent parallel resistance and inductance, which has been neglected by the FBO method. A simulation code including the parallel equivalent resistance and inductance has been set up. The simulation and experiments result in dramatically large arc shorting currents due to the parallel inductance effect. The case shows that the core snubber utilizing the FBO method gives more compact design.
基金supported by the National Natural Science Foundation of China(Nos.21506076,51678279 and 51508230)the National Science and Technological Support of China(No.2014BAC25B01)
文摘In this study, a full-scale internal circulation(IC) reactor coupled with an external circulation system was developed to treat high-strength leachate from a municipal solid waste(MSW)incineration plant, in which anaerobic sludge granulation was intensively investigated. Results showed that the IC reactor achieved excellent treatment performance under high organic loading rates(OLR) of 21.06–25.16 kg chemical oxygen demand(COD)/(m3? day). The COD removal efficiency and biogas yield respectively reached 89.4%–93.4% and 0.42–0.50 m3/kg COD.The formation of extracellular polymeric substances(EPS) was closely associated with sludge granulation. Protein was the dominant component in sludge EPS, and its content was remarkably increased from 21.6 to 99.7 mg/g Volatile Suspended Solid(VSS) during the reactor operation. The sludge Zeta potential and hydrophobicity positively correlated with the protein/polysaccharide ratio in EPS, and they were respectively increased from-26.2 m V and 30.35% to-10.6 m V and 78.67%, which was beneficial to microbial aggregation. Three-dimensional fluorescence spectroscopy(3 D-EEM) and Fourier transform infrared spectroscopy(FT-IR)analysis further indicated the importance of protein-like EPS substances in the sludge granulation. Moreover, it was also found that the secondary structures of EPS proteins varied during the reactor operation.
基金supported by the National Natural Science Foundation of China(No.51908536)the Ministry of Science and Technology of China(No.2018YFE0204103)。
文摘The degradation of atrazine (ATZ),sulfamethoxazole (SMX) and metoprolol (MET) in flowthrough VUV/UV/H2O2reactors was investigated with a focus on the effects of H2O2dosage and reactor internal diameter (ID).Results showed that the micropollutants were degraded efficiently in the flow-through VUV/UV/H2O2reactors following the pseudo first-order kinetics (R2>0.92).However,the steady-state assumption (SSA) kinetic model being vital in batch reactors was found invalid in flow-through reactors where fluid mixing was less sufficient.With the increase of H2O2dosage,the ATZ removal efficiency remained almost constant while the SMX and MET removal was enhanced to different extents,which could be explained by the different reactivities of the pollutants towards HO·.A larger reactor ID resulted in lower degradation rate constants for all the three pollutants on account of the lower average fluence rate,but the change in energy efficiency was much more complicated.In reality,the electrical energy per order (EEO) of the investigated VUV/UV/H2O2treatments ranged between 0.14–0.20,0.07–0.14 and 0.09–0.26 k Wh/m3/order for ATZ,SMX and MET,respectively,with the lowest EEOfor each pollutant obtained under varied H2O2dosages and reactor IDs.This study has demonstrated the efficiency of VUV/UV/H2O2process for micropollutant removal and the inadequacy of the SSA model in flow-through reactors,and elaborated the influential mechanisms of H2O2dosage and reactor ID on the reactor performances.