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Seiji Shiroya - One of the best experts on this subject based on the ideXlab platform.
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Measurement and analysis of 241Am Fission Rate ratio relative to 235U Fission Rate in thermal neutron systems using Kyoto University Critical Assembly
Journal of Nuclear Science and Technology, 2001Co-Authors: Hironobu Unesaki, Tomohiko Iwasaki, Takanori Kitada, Yoshitaka Ikeuchi, Seiji ShiroyaAbstract:Integral measurements of241 Am Fission Rate ratio relative to235 U Fission Rate were performed at Kyoto University Critical Assembly. The Fission Rates were measured using the back-to-back type double Fission chamber at five thermal cores with different H/235 U ratio so that the neutron spectra of the cores were systematically varied. The measured Fission Rate ratios, normalized to number of atoms, were 0. 0144 to 0. 0522, with a typical uncertainty of 2%. The measured data were compared with the calculated results using MVP based on JENDL-3.2, which gave the averaged calculated-to-experimental ratio (C/E) of 0.88. Obtained results of C/E using 241Am Fission cross sections from JENDL-3/2, ENDF/B-VI and JEF2.2 showed that the latter two gave larger C/E values than those by JENDL-3.2 by about 2% and 7 to 9%, respectively. It has been found that the large difference between JENDL-3.2 and JEF2.2 arises mainly from the significant cross section difference at the vicinity of resonance at 0.576 eV, whereas the d...
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measurement of 237np Fission Rate ratio relative to 235u Fission Rate in cores with various thermal neutron spectrum at the kyoto university critical assembly
Journal of Nuclear Science and Technology, 2000Co-Authors: Hironobu Unesaki, Tomohiko Iwasaki, Takanori Kitada, Akio Kohashi, Daisuke Fujiwara, Mitsuo Kuroda, Takeshi Kato, Yoshitaka Ikeuchi, Seiji ShiroyaAbstract:Integral measurements of 237 Np Fission Rate ratio relative to 235 U Fission Rate have been performed at Kyoto University Critical Assembly. The Fission Rates have been measured using the back-to-back type double Fission chamber at five thermal cores with different H/ 235 U ratio so that the neutron spectra of the cores were systematically varied. The measured Fission Rate ratio per atom was 0.00439 to 0.0298, with a typical uncertainty of 2 to 3%. The measured data were compared with the calculated results using SRAC/TWOTRAN and MVP based on JENDL-3.2, which gave the averaged C/E values of 0.93 and 0.95, respectively. Obtained results of C/E using 237 Np cross sections from JENDL-3/2, ENDF/B-VI.5 and JEF2.2 show that the latter two gave smaller results than JENDL-3.2 by about 4%, which clearly reflects the discrepancy in the evaluated cross section among the libraries. This difference arises from both fast Fission and resonance region. Although further improvement is recommended, 237 Np Fission cross section in JENDL-3.2 is considered to be superior to those in the other libraries and can be adopted for use in design calculations for minor actinide transmutation system using thermal reactors with prediction precision of 237 Np Fission Rate within 10%.
Luka Snoj - One of the best experts on this subject based on the ideXlab platform.
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Reaction Rate Benchmark Experiments with Miniature Fission Chambers at the Slovenian TRIGA Mark II Reactor
EPJ Web of Conferences, 2018Co-Authors: Žiga Štancar, Loïc Barbot, Christophe Destouches, D. Fourmentel, Luka Snoj, Tanja Kaiba, Jean-francois VillardAbstract:A series of Fission Rate profile measurements with miniature Fission chambers, developed by the Commisariat a l’energie atomique et auxenergies alternatives, were performed at the Jožef Stefan Institute’s TRIGA research reactor. Two types of Fission chambers with different Fissionable coating ( 235 U and 238 U) were used to perform axial Fission Rate profile measurements at various radial positions and several control rod configurations. The experimental campaign was supported by an extensive set of computations, based on a validated Monte Carlo computational model of the TRIGA reactor. The computing effort included neutron transport calculations to support the planning and design of the experiments as well as calculations to aid the evaluation of experimental and computational uncertainties and major biases. The evaluation of uncertainties was performed by employing various types of sensitivity analyses such as experimental parameter perturbation and core reaction Rate gradient calculations. It has been found that the experimental uncertainty of the measurements is sufficiently low, i.e. the total relative Fission Rate uncertainty being approximately 5 %, in order for the experiments to serve as benchmark experiments for validation of Fission Rate profiles. The effect of the neutron flux redistribution due to the control rod movement was studied by performing measurements and calculations of Fission Rates and Fission chamber responses in different axial and radial positions at different control rod configurations. It was confirmed that the control rod movement affects the position of the maximum in the axial Fission Rate distribution, as well as the height of the local maxima. The optimal detector position, in which the redistributions would have minimum effect on its signal, was determined.
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Computational validation of the Fission Rate distribution experimental benchmark at the JSI TRIGA Mark II research reactor using the Monte Carlo method
Annals of Nuclear Energy, 2018Co-Authors: Žiga Štancar, Loïc Barbot, Christophe Destouches, D. Fourmentel, Jean-francois Villard, Luka SnojAbstract:Abstract A Fission Rate profile benchmark experiment has been performed at the Jožef Stefan Institute TRIGA Mark II reactor. The measurements were made using absolutely calibRated miniature Fission chambers developed and manufactured by the Commissariat a l’Energie Atomique et aux Energies Alternatives. The aim of the paper is to describe the experimental set-up, Fission Rate measurements and to present the detailed Monte Carlo computational model of the TRIGA reactor, which was constructed with as used to compute absolute Fission Rate distributions in the core at a fixed control rod position, taking into account the detailed description of the experimental configuration. The paper focuses on the extensive evaluation of experimental and calculational uncertainties and biases following the International Reactor Physics Experiment Evaluation Project methodology. A comparison between the measured and computed absolute reaction Rates concludes the paper, with the agreement being within one sigma standard uncertainty.
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Evaluation of neutron flux and Fission Rate distributions inside the JSI TRIGA Mark II reactor using multiple in-core Fission chambers
Annals of Nuclear Energy, 2018Co-Authors: Tanja Goričanec, Loïc Barbot, Christophe Destouches, Gašper Žerovnik, Damien Fourmentel, Anže Jazbec, Luka SnojAbstract:Within the bilateral project between the CEA Cadarache and the Jožef Stefan Institute (JSI) a wide variety of measurements using multiple Fission chambers simultaneously inside the reactor core were performed. The Fission Rate axial profiles were measured at different measuring positions and at different control rod configurations. A relative comparison of calculated Fission Rates using the MCNP code and the measured Fission Rates was performed. In general the agreement between the measurements and calculations is good, with deviations within the uncertainties. For better observation and understanding of neutron flux redistributions due to the control rod movement, the neutron flux and Fission Rate had been tallied through the entire reactor core at different control rod configurations. The optimal detector position with minimum signal variations due to the control rod movement was determined.
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Evaluation of neutron flux and Fission Rate distributions inside the JSI TRIGA Mark II reactor using multiple in-core Fission chambers
Annals of Nuclear Energy, 2018Co-Authors: Tanja Goričanec, Loïc Barbot, Christophe Destouches, D. Fourmentel, Gašper Žerovnik, Anže Jazbec, Luka SnojAbstract:Abstract Within the bilateral project between the CEA Cadarache and the Jožef Stefan Institute (JSI) a wide variety of measurements using multiple Fission chambers simultaneously inside the reactor core were performed. The Fission Rate axial profiles were measured at different positions in the reactor core and at different control rod configurations. A relative comparison of the calculated Fission Rates using the MCNP code and the measured Fission Rates was performed. In general the agreement between the measurements and calculations is good, with the deviations within the uncertainties. For better observation and understanding of the neutron flux redistribution due to the control rod movement, the neutron flux and Fission Rate had been calculated through the entire reactor core for different control rod configurations. The detector position with minimum signal variations due to the regulating and compensating control rod movement during normal operation was determined. The minimum variation is optimal in case we want to reliably determine the reactor power without influence of the regulating and compensating control rod positions.
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Evaluation of biases and experimental uncertainties of the Fission Rate profile measurements at the JSI TRIGA Mark II research reactor
2015Co-Authors: Žiga Štancar, Luka Snoj, Loïc BarbotAbstract:The paper focuses on a validation experiment performed at the JSI TRIGA research reactor using two absolutely calibRated CEA developed miniature Fission chambers. These were used to measure a set of axial Fission Rate profiles through the height of the reactor core which were compared to reaction Rate profiles computed using the Monte Carlo method. The purpose of the paper is to describe the support calculations and methodology used in the evaluation of the experimental and computational biases and uncertainties. This includes the study of the effect of the Fission chamber structure and the aluminum guide tubes used for in-core insertion on the Fission Rate measurements as well as a detailed description of the influence of fuel material data error and fuel burn-up on the experimental uncertainty and computational biases. It is shown that the insertion of Fission chambers and guide tubes into the core of the TRIGA reactor significantly influences the local neutron spectrum and consequently the Fission Rate measurements one can observe an up to 15 % decrease. A similar effect was recorded when modelling the fuel burnup, where a 10 % deficit of $^{235}$U mass results in an approximately 10 % decrease in Fission Rates
Rong Liu - One of the best experts on this subject based on the ideXlab platform.
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Determination of thorium Fission Rate based on 135I in thorium oxide cylinder bombarded by D-T fusion neutrons
Annals of Nuclear Energy, 2018Co-Authors: Lei Zheng, Rong Liu, Yiwei Yang, Zhujun Liu, Mei Wang, Li Jiang, Zhongwei Wen, Kan Wang, Xingyan LiuAbstract:Abstract Aiming at developing the activation method and provide reference for the validation of thorium Fission parameters, a dedicated integral experiment was carried out in a thorium oxide cylinder bombard by D-T fusion neutrons. Thorium Fission Rate in the axial direction of the cylinder was determined by detecting the 1260.409 keV gamma emitted from Fission product 135I, with experimental uncertainties of 6.2%. MCNP calculations employing ENDF/B-VII.0, ENDF/B-VII.1, JENDL-4.0, CENDL-3.1 library data were in good agreement with measured thorium Fission Rates within experimental uncertainties. The agreement of measured reaction Rates of monitors with the calculations on the whole demonstRated the reliability of this experiment in some degree, and could provide reference for the analyses of thorium Fission Rates. Neutron spectra and the contribution of neutrons in each sub-energy range to thorium Fission Rate were also analyzed. The activation method to determine thorium Fission Rate was developed and the data obtained in this work could provide reference for the validation of thorium Fission parameters.
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Experimental and simulative studies of thorium Fission Rates on thorium oxide/depleted uranium cylinders with D-T neutrons
Progress in Nuclear Energy, 2017Co-Authors: Lei Zheng, Rong Liu, Yiwei Yang, Mei Wang, Li Jiang, Song Feng, Zijie HanAbstract:Abstract Aiming at validating thorium Fission parameters and the code used in the conceptual design of fusion-Fission hybrid energy reactor, an integral experiment on thorium oxide/depleted uranium cylinder assemblies for thorium Fission Rate has been carried out with D-T neutrons. Thorium Fission Rate in the axial direction of the assemblies was obtained by adopting the activation method, and the experimental uncertainties were 5.6–5.9%. MCNP simulation employing ENDF/B-VII.0 and ENDF/B-VII.1 library data were 5%–21% smaller than experimental ones. The influence of the polyethylene oxide (PEO) in the thorium oxide cylinders, evaluated by MCNP simulation employing ENDF/B-VII.0 library data, is negligible in the present thorium/uranium assemblies under the measured level. The difference between the present results and our previous ones was also analyzed. The stage experimental results could provide reference for the evaluation of neutron-induced thorium Fission cross section, and should be considered in the margin of the conceptual design of FFHER.
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Measurement and analysis of thorium Fission Rate in a polyethylene shell with a D-T neutron source
Fusion Engineering and Design, 2016Co-Authors: Lei Zheng, Rong Liu, Yiwei Yang, Zhujun Liu, Li Jiang, Mei WangAbstract:Abstract In order to validate the 232Th Fission cross section, an integral experiment was carried out using the activation method in a polyethylene shell with a D-T neutron source. Thorium samples were arranged in the 0° direction to the incident D+ beam. The 232Th Fission Rate was determined by measuring the 151.195 keV characteristic γ ray emitted from the Fission fragment 85mKr, and the experimental uncertainties were about 5.3%. MCNP calculation results employing ENDF/B-VII.0, JENDL-3.3, JENDL-4.0 libraries are in good agreement with that of experiments within uncertainties except that employing ENDF/B-VII.1 (∼6.5%). The experiment results can be used to re-evaluate the 232Th Fission cross section.
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Measurement and analysis of Fission Rates in depleted uranium and depleted uranium–polyethylene shells with neutrons from D-T reaction
Journal of Nuclear Science and Technology, 2015Co-Authors: Tonghua Zhu, Zijie Han, L. Jiang, Mei Wang, Chaowen Yang, Rong LiuAbstract:To validate the concept design of a novel fusion–Fission hybrid energy reactor, a depleted uranium assembly and a combined assembly of uranium and polyethylene were designed and assembled based on a depleted uranium spherical shell and a polyethylene spherical shell. The distribution of the Fission Rates for the depleted uranium and enriched uranium in the two assemblies, as a function of the distance of the detection position to the centre, was measured using a plate Fission chamber bombarded by D-T neutrons. The addition of a polyethylene shell significantly changed the neutron spectrum; in particular, the neutron fluxes with energies of 1 MeV and lower were changed. Using MCNP5 and the attached libraries, the Fission Rate experiments were simulated, and the experimental configuration, including the wall of the experimental hall, was described in detail in the model. The Fission Rate distributions for depleted uranium and enriched uranium in the two assemblies were reproducible. The difference between t...
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Benchmark analysis of Fission-Rate distributions in a series of spherical depleted-uranium assemblies for hybrid-reactor design
Annals of Nuclear Energy, 2014Co-Authors: T.h. Zhu, C.w. Yang, Rong Liu, Zijie Han, L. Jiang, Wang MeicongAbstract:The nuclear performance of a Fission blanket in a hybrid reactor has been validated by analyzing Fission-Rate experiments with a series of spherical depleted-uranium assemblies. Calculations were made with the Monte–Carlo transport code MCNP5 and the ENDF/B-V.0 continuous-energy cross sections and compared to the measured results. The ratios of calculated to experimental values (C/E) for the Fission Rate and the Fission-Rate ratio of 238U to 235U are presented along with a discussion of the validation of the ENDF/B-V.0 library regarding its use in the design of the Fission blanket. Overestimations are observed in the calculation of the 238U and 235U Fission Rates at all positions, except the ones near the outer surfaces of the assemblies, and the C/Es of the Fission Rate decreased as the thickness of the depleted-uranium (DU) layer increased, while most of the C/Es of the Fission-Rate ratio of 238U to 235U were close to unity, being within the range of 0.95–1.05.
Hironobu Unesaki - One of the best experts on this subject based on the ideXlab platform.
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Measurement and analysis of 241Am Fission Rate ratio relative to 235U Fission Rate in thermal neutron systems using Kyoto University Critical Assembly
Journal of Nuclear Science and Technology, 2001Co-Authors: Hironobu Unesaki, Tomohiko Iwasaki, Takanori Kitada, Yoshitaka Ikeuchi, Seiji ShiroyaAbstract:Integral measurements of241 Am Fission Rate ratio relative to235 U Fission Rate were performed at Kyoto University Critical Assembly. The Fission Rates were measured using the back-to-back type double Fission chamber at five thermal cores with different H/235 U ratio so that the neutron spectra of the cores were systematically varied. The measured Fission Rate ratios, normalized to number of atoms, were 0. 0144 to 0. 0522, with a typical uncertainty of 2%. The measured data were compared with the calculated results using MVP based on JENDL-3.2, which gave the averaged calculated-to-experimental ratio (C/E) of 0.88. Obtained results of C/E using 241Am Fission cross sections from JENDL-3/2, ENDF/B-VI and JEF2.2 showed that the latter two gave larger C/E values than those by JENDL-3.2 by about 2% and 7 to 9%, respectively. It has been found that the large difference between JENDL-3.2 and JEF2.2 arises mainly from the significant cross section difference at the vicinity of resonance at 0.576 eV, whereas the d...
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measurement of 237np Fission Rate ratio relative to 235u Fission Rate in cores with various thermal neutron spectrum at the kyoto university critical assembly
Journal of Nuclear Science and Technology, 2000Co-Authors: Hironobu Unesaki, Tomohiko Iwasaki, Takanori Kitada, Akio Kohashi, Daisuke Fujiwara, Mitsuo Kuroda, Takeshi Kato, Yoshitaka Ikeuchi, Seiji ShiroyaAbstract:Integral measurements of 237 Np Fission Rate ratio relative to 235 U Fission Rate have been performed at Kyoto University Critical Assembly. The Fission Rates have been measured using the back-to-back type double Fission chamber at five thermal cores with different H/ 235 U ratio so that the neutron spectra of the cores were systematically varied. The measured Fission Rate ratio per atom was 0.00439 to 0.0298, with a typical uncertainty of 2 to 3%. The measured data were compared with the calculated results using SRAC/TWOTRAN and MVP based on JENDL-3.2, which gave the averaged C/E values of 0.93 and 0.95, respectively. Obtained results of C/E using 237 Np cross sections from JENDL-3/2, ENDF/B-VI.5 and JEF2.2 show that the latter two gave smaller results than JENDL-3.2 by about 4%, which clearly reflects the discrepancy in the evaluated cross section among the libraries. This difference arises from both fast Fission and resonance region. Although further improvement is recommended, 237 Np Fission cross section in JENDL-3.2 is considered to be superior to those in the other libraries and can be adopted for use in design calculations for minor actinide transmutation system using thermal reactors with prediction precision of 237 Np Fission Rate within 10%.
Zijie Han - One of the best experts on this subject based on the ideXlab platform.
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Experimental and simulative studies of thorium Fission Rates on thorium oxide/depleted uranium cylinders with D-T neutrons
Progress in Nuclear Energy, 2017Co-Authors: Lei Zheng, Rong Liu, Yiwei Yang, Mei Wang, Li Jiang, Song Feng, Zijie HanAbstract:Abstract Aiming at validating thorium Fission parameters and the code used in the conceptual design of fusion-Fission hybrid energy reactor, an integral experiment on thorium oxide/depleted uranium cylinder assemblies for thorium Fission Rate has been carried out with D-T neutrons. Thorium Fission Rate in the axial direction of the assemblies was obtained by adopting the activation method, and the experimental uncertainties were 5.6–5.9%. MCNP simulation employing ENDF/B-VII.0 and ENDF/B-VII.1 library data were 5%–21% smaller than experimental ones. The influence of the polyethylene oxide (PEO) in the thorium oxide cylinders, evaluated by MCNP simulation employing ENDF/B-VII.0 library data, is negligible in the present thorium/uranium assemblies under the measured level. The difference between the present results and our previous ones was also analyzed. The stage experimental results could provide reference for the evaluation of neutron-induced thorium Fission cross section, and should be considered in the margin of the conceptual design of FFHER.
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Measurement and analysis of Fission Rates in depleted uranium and depleted uranium–polyethylene shells with neutrons from D-T reaction
Journal of Nuclear Science and Technology, 2015Co-Authors: Tonghua Zhu, Zijie Han, L. Jiang, Mei Wang, Chaowen Yang, Rong LiuAbstract:To validate the concept design of a novel fusion–Fission hybrid energy reactor, a depleted uranium assembly and a combined assembly of uranium and polyethylene were designed and assembled based on a depleted uranium spherical shell and a polyethylene spherical shell. The distribution of the Fission Rates for the depleted uranium and enriched uranium in the two assemblies, as a function of the distance of the detection position to the centre, was measured using a plate Fission chamber bombarded by D-T neutrons. The addition of a polyethylene shell significantly changed the neutron spectrum; in particular, the neutron fluxes with energies of 1 MeV and lower were changed. Using MCNP5 and the attached libraries, the Fission Rate experiments were simulated, and the experimental configuration, including the wall of the experimental hall, was described in detail in the model. The Fission Rate distributions for depleted uranium and enriched uranium in the two assemblies were reproducible. The difference between t...
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Benchmark analysis of Fission-Rate distributions in a series of spherical depleted-uranium assemblies for hybrid-reactor design
Annals of Nuclear Energy, 2014Co-Authors: T.h. Zhu, C.w. Yang, Rong Liu, Zijie Han, L. Jiang, Wang MeicongAbstract:The nuclear performance of a Fission blanket in a hybrid reactor has been validated by analyzing Fission-Rate experiments with a series of spherical depleted-uranium assemblies. Calculations were made with the Monte–Carlo transport code MCNP5 and the ENDF/B-V.0 continuous-energy cross sections and compared to the measured results. The ratios of calculated to experimental values (C/E) for the Fission Rate and the Fission-Rate ratio of 238U to 235U are presented along with a discussion of the validation of the ENDF/B-V.0 library regarding its use in the design of the Fission blanket. Overestimations are observed in the calculation of the 238U and 235U Fission Rates at all positions, except the ones near the outer surfaces of the assemblies, and the C/Es of the Fission Rate decreased as the thickness of the depleted-uranium (DU) layer increased, while most of the C/Es of the Fission-Rate ratio of 238U to 235U were close to unity, being within the range of 0.95–1.05.