We proposed and compared three methods(filter burnup,single energy burnup,and burnup extremum analysis)to build a high-resolution neutronics model for 238Pu production in high-flux reactors.The filter burnup and singl...We proposed and compared three methods(filter burnup,single energy burnup,and burnup extremum analysis)to build a high-resolution neutronics model for 238Pu production in high-flux reactors.The filter burnup and single energy burnup methods have no theoretical approximation and can achieve a spectrum resolution of up to~1 eV,thereby constructing the importance curve and yield curve of the full energy range.The burnup extreme analysis method combines the importance and yield curves to consider the influence of irradiation time on production efficiency,thereby constructing extreme curves.The three curves,which quantify the transmutation rate of the nuclei in each energy region,are of physical significance because they have similar distributions.A high-resolution neutronics model for ^(238)Pu production was established based on these three curves,and its universality and feasibility were proven.The neutronics model can guide the neutron spectrum optimization and improve the yield of ^(238)Pu by up to 18.81%.The neutronics model revealed the law of nuclei transmutation in all energy regions with high spectrum resolution,thus providing theoretical support for high-flux reactor design and irradiation production of ^(238)Pu.展开更多
Objectives: To determine the economic challenges brought on by water-borne illnesses as a result of climate change. In addition to identifying potential access to safe drinking water during climate change and potentia...Objectives: To determine the economic challenges brought on by water-borne illnesses as a result of climate change. In addition to identifying potential access to safe drinking water during climate change and potential health hurdles brought on by water-related diseases, it is important to learn how to reduce the spread of water-borne diseases. Methods: A mixed method design was adopted to evaluate this research, and probability sampling, more specifically simple random sampling, was used to select to sample from the target population. The study was conducted in Taltali upazila of the Barguna district, and data was collected from 384 respondents;among them, 5 respondents were selected for the key informant interview. The research project began in June 2022 and was completed in December 2022. Results: 41.4% of respondents said they suffer from dysentery, 22.4% said the expense of treating water-borne diseases has increased as a result of climate change, and 37.8% said they must travel great distances to obtain clean drinking water. Currently, 41.7% of individuals utilize tube-well water, compared to 19.3% five to ten years ago, and 27.4% have been taught that water filtration helps reduce the spread of water-borne diseases. Conclusions: People’s vulnerability to climate change in the study area is a result of factors such as rapid population increase, unequal access to resources, food insecurity, a long distance to collect water, inadequate medical facilities, a lack of poverty, and a weak health system.展开更多
A passive neutron multiplicity measurement device,FH-NCM/S1,based on field-programmable gate arrays(FPGAs),is developed specifically for measuring the mass of plutonium-240(^(240)Pu)in mixed oxide fuel.FH-NCM/S1 adopt...A passive neutron multiplicity measurement device,FH-NCM/S1,based on field-programmable gate arrays(FPGAs),is developed specifically for measuring the mass of plutonium-240(^(240)Pu)in mixed oxide fuel.FH-NCM/S1 adopts an inte-grated approach,combining the shift register analysis mode with the pulse-position timestamp mode using an FPGA.The optimal effective length of the^(3)He neutron detector was determined to be 30 cm,and the thickness of the graphite reflector was ascertained to be 15 cm through MCNP simulations.After fabricating the device,calibration measurements were per-formed using a^(252)Cf neutron source;a detection efficiency of 43.07%and detector die-away time of 55.79μs were observed.Nine samples of plutonium oxide were measured under identical conditions using the FH-NCM/S1 in shift register analysis mode and a plutonium waste multiplicity counter.The obtained double rates underwent corrections for detection efficiency(ε)and double gate fraction(f_(d)),resulting in corrected double rates(D_(c)),which were used to validate the accuracy of the shift register analysis mode.Furthermore,the device exhibited fluctuations in the measurement results,and within a single 20 s measurement,these fluctuations remained below 10%.After 30 cycles,the relative error in the mass of^(240)Pu was less than 5%.Finally,correlation calculations confirmed the robust consistency of both measurement modes.This study holds specific significance for the subsequent design and development of neutron multiplicity devices.展开更多
基金supported by Natural Science Foundation of China (No. 12305190)Lingchuang Research Project of China National Nuclear Corporation (CNNC)the Science and Technology on Reactor System Design Technology Laboratory
文摘We proposed and compared three methods(filter burnup,single energy burnup,and burnup extremum analysis)to build a high-resolution neutronics model for 238Pu production in high-flux reactors.The filter burnup and single energy burnup methods have no theoretical approximation and can achieve a spectrum resolution of up to~1 eV,thereby constructing the importance curve and yield curve of the full energy range.The burnup extreme analysis method combines the importance and yield curves to consider the influence of irradiation time on production efficiency,thereby constructing extreme curves.The three curves,which quantify the transmutation rate of the nuclei in each energy region,are of physical significance because they have similar distributions.A high-resolution neutronics model for ^(238)Pu production was established based on these three curves,and its universality and feasibility were proven.The neutronics model can guide the neutron spectrum optimization and improve the yield of ^(238)Pu by up to 18.81%.The neutronics model revealed the law of nuclei transmutation in all energy regions with high spectrum resolution,thus providing theoretical support for high-flux reactor design and irradiation production of ^(238)Pu.
文摘Objectives: To determine the economic challenges brought on by water-borne illnesses as a result of climate change. In addition to identifying potential access to safe drinking water during climate change and potential health hurdles brought on by water-related diseases, it is important to learn how to reduce the spread of water-borne diseases. Methods: A mixed method design was adopted to evaluate this research, and probability sampling, more specifically simple random sampling, was used to select to sample from the target population. The study was conducted in Taltali upazila of the Barguna district, and data was collected from 384 respondents;among them, 5 respondents were selected for the key informant interview. The research project began in June 2022 and was completed in December 2022. Results: 41.4% of respondents said they suffer from dysentery, 22.4% said the expense of treating water-borne diseases has increased as a result of climate change, and 37.8% said they must travel great distances to obtain clean drinking water. Currently, 41.7% of individuals utilize tube-well water, compared to 19.3% five to ten years ago, and 27.4% have been taught that water filtration helps reduce the spread of water-borne diseases. Conclusions: People’s vulnerability to climate change in the study area is a result of factors such as rapid population increase, unequal access to resources, food insecurity, a long distance to collect water, inadequate medical facilities, a lack of poverty, and a weak health system.
基金supported by the National Natural Science Foundation of China(No.42374226)Natural Science Foundation of Jiangxi Province(Nos.20232BAB201043 and 20232BCJ23006)+1 种基金a sub-project of the nuclear energy development project of the China National Defense Science and Industry Bureau‘n-γfusion logging method theory research’(No.20201192-01)the Fundamental Science on Radioactive Geology and Exploration Technology Laboratory(No.2022RGET20)。
文摘A passive neutron multiplicity measurement device,FH-NCM/S1,based on field-programmable gate arrays(FPGAs),is developed specifically for measuring the mass of plutonium-240(^(240)Pu)in mixed oxide fuel.FH-NCM/S1 adopts an inte-grated approach,combining the shift register analysis mode with the pulse-position timestamp mode using an FPGA.The optimal effective length of the^(3)He neutron detector was determined to be 30 cm,and the thickness of the graphite reflector was ascertained to be 15 cm through MCNP simulations.After fabricating the device,calibration measurements were per-formed using a^(252)Cf neutron source;a detection efficiency of 43.07%and detector die-away time of 55.79μs were observed.Nine samples of plutonium oxide were measured under identical conditions using the FH-NCM/S1 in shift register analysis mode and a plutonium waste multiplicity counter.The obtained double rates underwent corrections for detection efficiency(ε)and double gate fraction(f_(d)),resulting in corrected double rates(D_(c)),which were used to validate the accuracy of the shift register analysis mode.Furthermore,the device exhibited fluctuations in the measurement results,and within a single 20 s measurement,these fluctuations remained below 10%.After 30 cycles,the relative error in the mass of^(240)Pu was less than 5%.Finally,correlation calculations confirmed the robust consistency of both measurement modes.This study holds specific significance for the subsequent design and development of neutron multiplicity devices.
