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Journal Articles

Measurement of prompt neutron decay constant with spallation neutrons at Kyoto University Critical Assembly using linear combination method

Katano, Ryota; Yamanaka, Masao*; Pyeon, C. H.*

Journal of Nuclear Science and Technology, 57(2), p.169 - 176, 2020/02

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

We proposed the linear combination method as a subcriticality measurement method which estimates the prompt neutron decay constant ($$alpha$$) correlated with the subcriticality using measurement results obtained at multiple detector positions. In the previous study, we confirmed applicability of the linear combination method through the pulsed neutron experiment with DT neutron source at Kyoto University Critical Assembly (KUCA). In this study, we conduct the pulsed neutron source experiment with spallation neutrons at KUCA and confirm the robustness of the linear combination to neutron sources.

Journal Articles

Application of linear combination method to pulsed neutron source measurement at Kyoto University Critical Assembly

Katano, Ryota; Yamanaka, Masao*; Pyeon, C. H.*

Nuclear Science and Engineering, 193(12), p.1394 - 1402, 2019/12

 Times Cited Count:2 Percentile:28.85(Nuclear Science & Technology)

The author proposed the linear combination method as a subcriticality measurement method which estimates the prompt neutron decay constant (alpha) correlated with the subcriticality using measurement results obtained at multiple detector positions. In this study, we conduct the pulsed neutron experiment at Kyoto University Critical Assembly (KUCA) and measure alpha by the linear combination method using measured neutron counts. Through experiment, we experimentally show that the linear combination method can reduce the higher-mode effect compared to the conventional method. In addition, experimentally show that the linear combination has capability of the different mode extraction.

Journal Articles

Design of accelerator-driven system consistent to partitioning technology

Sugawara, Takanori; Ban, Yasutoshi; Katano, Ryota; Tateno, Haruka; Nishihara, Kenji

Proceedings of International Conference on the Management of Spent Fuel from Nuclear Power Reactors 2019 (Internet), 9 Pages, 2019/06

The JAEA has proposed the double-strata strategy which will introduce a dedicated minor actinide (MA) transmutation cycle using an accelerator-driven system (ADS). In the previous study, the ideal fuel condition was supposed in the neutronics design of the ADS. For example, impurities such as rare earth (RE) nuclides which would accompany with MA, were not assumed. However, these nuclides would accompany with the ADS fuel and the capture reaction of these nuclides deteriorates the neutron economy of the ADS core. This study investigates a new fuel composition based on the SELECT (Solvent Extraction from Liquid-waste using Extractants of CHON-type for Transmutation) process proposed by JAEA. By performing the neutronics calculation of the ADS with the new fuel composition, a feasibility of the new fuel composition will be investigated.

Journal Articles

Area ratio method via linear combination of the neutron counts in pulsed neutron experiment

Katano, Ryota

Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 6 Pages, 2019/05

no abstracts in English

Journal Articles

Estimation method of prompt neutron decay constant reducing higher order mode effect by linear combination

Katano, Ryota

Nuclear Science and Engineering, 193(4), p.431 - 439, 2019/04

 Times Cited Count:3 Percentile:16.3(Nuclear Science & Technology)

We proposed "linear combination method" to reduce the higher order mode effect on the prompt neutron decay constant measured by the pulsed neutron experiment. When the spatial higher order mode effect is taken into account, the time evolution of the neutron counts after the pulsed neutron injection is given by linear combination of multiple exponential functions. However, the measurement results by the conventional method include the systematic error derived from the higher order mode effect because the conventional method fit the neutron counts with a single exponential function. The proposed method extract the single exponential function of the fundamental mode by linear combination of the neutron counts at multiple detectors, thus the proposed method reduces the higher order mode effect. As the verification, we applied the proposed method to the numerical simulation. The results indicate that the proposed method can reduce the higher order mode effect by linear combination.

Journal Articles

Journal Articles

Estimation of sensitivity coefficient based on lasso-type penalized linear regression

Katano, Ryota; Endo, Tomohiro*; Yamamoto, Akio*; Tsujimoto, Kazufumi

Journal of Nuclear Science and Technology, 55(10), p.1099 - 1109, 2018/10

 Times Cited Count:2 Percentile:52.02(Nuclear Science & Technology)

In this study, we propose the penalized regression "adaptive smooth-lasso" for the estimation of sensitivity coefficients of the neutronics parameters. The proposed method estimates the sensitivity coefficients of the neutronics parameters using the variation of the microscopic cross sections and the neutronics parameter obtained by random sampling. The proposed method utilizes only the forward calculations. Thus, the proposed method can be applied for the complex reactor analysis for which the application of the adjoint method is difficult. In this study, we proposed a penalty term considering the characteristics of the sensitivity coefficients of the neutronics parameter to the microscopic multi-group cross sections. Through verification calculation, we show that the proposed method achieves high accuracy with less computational cost compared to the method based on random sampling proposed in the previous studies.

Journal Articles

Impact of impurity in transmutation cycle on neutronics design of revised accelerator-driven system

Sugawara, Takanori; Katano, Ryota; Tsujimoto, Kazufumi

Annals of Nuclear Energy, 111, p.449 - 459, 2018/01

 Times Cited Count:5 Percentile:18.88(Nuclear Science & Technology)

This study aims to review the ADS design based on the outcome for the last dozen years and to investigate the impact of impurities in the transmutation cycle on the ADS neutronics design. The impact of impurities in the transmutation cycle is investigated for the reviewed reference design. For the uranium from the partitioning, the accompaniment of 20 wt.% U against the Pu weight is acceptable although the MA transmutation amount will be decreased slightly. For the rare earth (RE) from the partitioning, the accompaniment of 5 wt.% RE against the MA weight is allowable. In the reprocessing, the decontamination factor, DF=10 for RE is enough from the viewpoint of the neutronics design. The impact of the fuel composition accuracy is also investigated. The uncertainty of the ZrN ratio against the MA fuel should be less than 0.2% to minimize a surplus proton beam current due to the uncertainty.

JAEA Reports

Effect of experiments using Transmutation Physics Experimental Facility on the reduction of uncertainties in reactor physics parameters of an accelerator-driven system

Iwamoto, Hiroki; Nishihara, Kenji; Katano, Ryota*; Fukushima, Masahiro; Tsujimoto, Kazufumi

JAEA-Research 2014-033, 82 Pages, 2015/03

JAEA-Research-2014-033.pdf:6.53MB

The effect of experiments using Transmutation Physics Experimental Facility (TEF-P) is analysed from the viewpoint of the reduction of uncertainties in reactor physics parameters (criticality and coolant void reactivity) of an accelerator-driven system (ADS). The analysis is conducted by the nuclear-data adjustment method using JENDL-4.0 on the assumption that ve types of reactor physics experiments (a total of 44 experiments) are performed in TEF-P: (1) criticality experiment, (2) lead void reactivity experiment, (3) reaction rate ratio experiment, (4) sample reactivity experiment, and (5) fuel replacement reactivity experiment. As the result, 1.0% of uncertainty in criticality is found to be reduced to approximately 0.4%, and effective experiments for the reduction of uncertainty in criticality and coolant void reactivity are shown to be fuel replacement reactivity experiments and lead void reactivity experiments, respectively. Although these effects depend largely on the composition and amount of minor-actinide (MA) fuels, it is found that a combination of different types of experiments and database of existing experiments is effective in reducing the uncertainties.

Oral presentation

Reduction of uncertainties in reactor physics parameters of an accelerator-driven system by minor-actinide loaded experiments at J-PARC

Iwamoto, Hiroki; Nishihara, Kenji; Katano, Ryota*; Fujimoto, Atsushi*

no journal, , 

no abstracts in English

Oral presentation

Development of generalized area ratio method for subcriticality measurement

Katano, Ryota; Nishihara, Kenji; Tsujimoto, Kazufumi; Endo, Tomohiro*

no journal, , 

no abstracts in English

Oral presentation

Impact of impurity in transmutation cycle on neutronics design of accelerator-driven system

Sugawara, Takanori; Katano, Ryota; Tsujimoto, Kazufumi

no journal, , 

This study aims to investigate the impact of impurities in the transmutation cycle on the ADS neutronics design. For the uranium from the partitioning, the accompaniment of 20 wt.% U against the Pu weight is acceptable although the MA transmutation amount will be decreased slightly. For the rare earth (RE) from the partitioning, the accompaniment of 5 wt.% RE against the MA weight is allowable. In the reprocessing, the decontamination factor, DF=10 for RE is enough from the viewpoint of the neutronics design.

Oral presentation

A Research for the estimation of a prompt neutron decay constant using linear combination method

Katano, Ryota; Tsujimoto, Kazufumi

no journal, , 

no abstracts in English

Oral presentation

The Estimation of a prompt neutron decay constant using linear combination method

Katano, Ryota; Tsujimoto, Kazufumi; Pyeon, C. H.*; Yamanaka, Masao*

no journal, , 

no abstracts in English

Oral presentation

Impact of impurity in transmutation cycle on neutronics design of accelerator-driven system

Sugawara, Takanori; Katano, Ryota; Tsujimoto, Kazufumi

no journal, , 

This study aims to investigate the impact of impurities in the transmutation cycle on the accelerator-driven system (ADS) neutronics design. For the uranium from the partitioning, the accompaniment of 20 wt.% U against the Pu weight is acceptable although the MA transmutation amount will be decreased slightly. For the rare earth (RE) from the partitioning, the accompaniment of 5 wt.% RE against the MA weight is allowable. In the reprocessing, the decontamination factor, DF=10 for RE is enough from the viewpoint of the neutronics design. Through these investigations, the required conditions for the impurities in the partitioning, the MA fuel fabrication and the reprocessing processes were clarified from the viewpoint of the ADS neutronics design.

Oral presentation

Oral presentation

V&V of JENDL using integral experiments

Katano, Ryota; Tada, Kenichi

no journal, , 

We briefly introduce some descriptions about Verification & Validation (V&V) of Japanese nuclear data library, JENDL. Then, we introduce some descriptions about an automatic nuclear data validation system VACANCE for efficient V&V as a related work.

Oral presentation

Minimum value of the $$alpha$$-mode eigenvalue of an accelerator driven system

Katano, Ryota

no journal, , 

no abstracts in English

Oral presentation

Application of linear combination method to ADS for subcriticality measurement

Katano, Ryota

no journal, , 

no abstracts in English

Oral presentation

Study on applicability of subcriticality measurement method to LBE cooled accelerator-driven system

Katano, Ryota

no journal, , 

We have proposed the linear combination method for accurate prompt neutron decay constant measurement, which improves accuracy of the $$alpha$$ fitting method using pulsed neutron source (PNS). In this study, we perform PNS simulation with a continuous energy Monte Carlo code to confirm applicability of the proposed method to ADS core. The results indicate that thermal neutrons, which have less contribution to fissions, have long lifetime due to small absorption cross sections of LBE nuclides and could degrade accuracy of $$alpha$$.

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