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Journal Articles

Comparison of sodium fast reactor core assembly seismic evaluation using the Japanese and French simulation tools

Yamamoto, Tomohiko; Matsubara, Shinichiro*; Harada, Hidenori*; Saunier, P.*; Martin, L.*; Gentet, D.*; Dirat, J.-F.*; Collignon, C.*

Nuclear Engineering and Design, 383, p.111406_1 - 111406_14, 2021/11

 Times Cited Count:0

Japan-France collaboration on ASTRID (Advanced Sodium Technological Reactor for Industrial Demonstration) project is launched in 2014. In this project, Japan-France evaluates core assemblies with interferences on seismic event. The object of this study is to verify the seismic evaluation method on core assemblies between Japan and France by comparing the results. The analysis of this benchmark calculation shows a satisfactory agreement between the Japanese and French tools and the figures show a good behavior of the core in horizontal direction under French seismic condition.

Journal Articles

How different is the core of $$^{25}$$F from $$^{24}$$O$$_{g.s.}$$ ?

Tang, T. L.*; Uesaka, Tomohiro*; Kawase, Shoichiro; Beaumel, D.*; Dozono, Masanori*; Fujii, Toshihiko*; Fukuda, Naoki*; Fukunaga, Taku*; Galindo-Uribarri, A.*; Hwang, S. H.*; et al.

Physical Review Letters, 124(21), p.212502_1 - 212502_6, 2020/05

 Times Cited Count:9 Percentile:88.96(Physics, Multidisciplinary)

The structure of a neutron-rich $$^{25}$$F nucleus is investigated by a quasifree ($$p,2p$$) knockout reaction. The sum of spectroscopic factors of $$pi 0d_{5/2}$$ orbital is found to be 1.0 $$pm$$ 0.3. The result shows that the $$^{24}$$O core of $$^{25}$$F nucleus significantly differs from a free $$^{24}$$O nucleus, and the core consists of $$sim$$35% $$^{24}$$O$$_{rm g.s.}$$, and $$sim$$65% excited $$^{24}$$O. The result shows that the $$^{24}$$O core of $$^{25}$$F nucleus significantly differs from a free $$^{24}$$O nucleus. The result may infer that the addition of the $$0d_{5/2}$$ proton considerably changes the neutron structure in $$^{25}$$F from that in $$^{24}$$O, which could be a possible mechanism responsible for the oxygen dripline anomaly.

Journal Articles

Comparison of sodium fast reactor core assembly seismic evaluation using the Japanese JAEA/MFBR/MHI and French CEA simulation tools

Yamamoto, Tomohiko; Matsubara, Shinichiro*; Harada, Hidenori*; Saunier, P.*; Martin, L.*; Gentet, D.*; Dirat, J.-F.*; Collignon, C.*

Proceedings of 2019 International Congress on Advances in Nuclear Power Plants (ICAPP 2019) (Internet), 8 Pages, 2019/05

Japan-France collaboration on ASTRID (Advanced Sodium Technological Reactor for Industrial Demonstration) project is launched in 2014. In this project, Japan-France evaluates core assemblies with interferences on seismic event. The object of this study is to verify the seismic evaluation method on core assemblies between Japan and France by comparing the results. The analysis of this benchmark calculation shows a satisfactory agreement between the Japanese and French tools and the figures show a good behavior of the core in horizontal direction under French seismic condition.

Journal Articles

Holding force tests of Curie Point Electro-Magnet in hot gas for passive shutdown system

Matsunaga, Shoko*; Matsubara, Shinichiro*; Kato, Atsushi; Yamano, Hidemasa; D$"o$derlein, C.*; Guillemin, E.*; Hirn, J.*

Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 8 Pages, 2019/05

This paper presents a design of Curie Point Electro-Magnet (CPEM) which will be installed as a passive shutdown system for a French Sodium-cooled Fast Reactor (ASTRID) development program which is conducted in collaboration between France and Japan. To confirm CPEM design validity, a qualification program for CPEM is developed on the basis of past comprehensive test series of Self-Actuated Shutdown System (SASS) in Japan. The main outcome of this paper is results of holding force tests in hot gas, which satisfy design requirements. Moreover, the result of a numerical magnetic field analysis showed the same tendency as that of the holding force test.

Journal Articles

Fast reactor core seismic experiment and analysis under strong excitation

Yamamoto, Tomohiko; Iwasaki, Akihisa*; Kawamura, Kazuki*; Matsubara, Shinichiro*; Harada, Hidenori*

Proceedings of 2018 ASME Pressure Vessels and Piping Conference (PVP 2018), 8 Pages, 2018/07

To design fast reactor (FR) core components, seismic response must be evaluated in order to ensure structural integrity. Thus, a core seismic analysis method has been developed to evaluate 3D core vibration behavior considering fluid structure interaction and vertical displacements (rising). 1/1.5 scale 37 core element mock-ups hexagonal-matrix experiment was performed to validate the core elements vibration analysis code in three dimensions (REVIAN-3D). Based on the test data, the analysis model newly incorporated to respond to strong excitation was verified.

Journal Articles

Incorporation of multinuclear copper active sites into nitrogen-doped graphene for electrochemical oxygen reduction

Kato, Masaru*; Muto, Marika*; Matsubara, Naohiro*; Uemura, Yohei*; Wakisaka, Yuki*; Yoneuchi, Tsubasa*; Matsumura, Daiju; Ishibara, Tomoko*; Tokushima, Takashi*; Noro, Shinichiro*; et al.

ACS Applied Energy Materials (Internet), 1(5), p.2358 - 2364, 2018/05

 Times Cited Count:4 Percentile:26.29(Chemistry, Physical)

Journal Articles

Core seismic experiment and analysis of full scale single model for fast reactor

Yamamoto, Tomohiko; Kitamura, Seiji; Iwasaki, Akihisa*; Matsubara, Shinichiro*; Okamura, Shigeki*

Proceedings of 2017 ASME Pressure Vessels and Piping Conference (PVP 2017) (CD-ROM), 10 Pages, 2017/07

To design fast reactor (FR) components, seismic response must be evaluated in order to ensure structural integrity. Therefore, a sophisticated analysis method has to be developed to study the seismic response of FR core. The fast reactors are made of several hundred core assemblies in hexagonal arrangement. When a big earthquake occurs, large horizontal displacement and impact force of each core assembly may cause a trouble for control rod insertability and core assembly intensity. Therefore, a seismic analysis method of fast reactor core considering horizontal nonlinear behavior, such as impact, fluid-structure interaction, etc. is needed. Validation of the core assembly vibration analysis code in three dimension (REVIAN-3D) was conducted by a full scale experiment. In this validation, the vertical behavior (raising displacement) and horizontal behavior (Impact force, horizontal response) of the analysis result agreed very well with the experiments.

Journal Articles

3D FEA elastoplastic structural analysis of hypothetically cracked Monju FBR core support structures

Garcia Rodriguez, D.; Matsubara, Shinichiro

Proceedings of 22nd International Conference on Nuclear Engineering (ICONE-22) (DVD-ROM), 9 Pages, 2014/07

Structural reliability of the circumferentially cracked core support mount of Monju FBR is analyzed using FEA. The 3D shell model employed was derived after detailed evaluation of the core support mount behavior with a specific 3D solid model. 1st, elastoplastic static analysis shows that, under nominal operating conditions, the overall structure would be able to survive a total loss of the core support mount. 2nd, using the double elastic slope method it was inferred that earthquake loading integrity could be warranted up to a crack representing over 50% of the total circumference.

Journal Articles

Change in the electrical performance of GaAs solar cells with InGaAs quantum dot layers by electron irradiation

Oshima, Takeshi; Sato, Shinichiro; Imaizumi, Mitsuru*; Nakamura, Tetsuya*; Sugaya, Takeyoshi*; Matsubara, Koji*; Niki, Shigeru*

Solar Energy Materials and Solar Cells, 108, p.263 - 268, 2013/01

 Times Cited Count:12 Percentile:51.84(Energy & Fuels)

GaAs solar cells which have a PiN structure with 50 self-organized In$$_{0.4}$$Ga$$_{0.6}$$As Quantum Dot (QD) layers were irradiated with 1 MeV electrons up to 1$$times$$10$$^{16}$$ /cm$$^{2}$$. After irradiation at 1$$times$$10$$^{16}$$/cm$$^{2}$$, the remaining factor of I$$_{rm SC}$$, V$$_{rm OC}$$ and P$$_{rm MAX}$$ for the InGaAs 50 QD solar cell becomes 80, 90 and 55% of the initial values, respectively. On the other hand, those values for non QD GaAs solar cells decrease to 95, 80 and 63% of the initial values, respectively. Since the i-layer for the 50 QD solar cells (1.1 $$mu$$m) is thicker than the non QD solar cells (660 nm), the larger degradation of I$$_{rm SC}$$ for the 50 QD solar cells than the non QD ones can be interpreted in terms that the carrier recombination in the i-layer for the 50 QD solar cells is larger than that for the non QD solar cells. For V$$_{rm OC}$$, the 50 QD solar cells showes better radiation resistance than the non QD solar cells. Furthermore, the annealing behavior of the electrical characteristics for the 50 QD and the non QD solar cells was investigated at RT under AM 0 immediately after the irradiation. As a result, the recovery of the electrical characteristics for both solar cells was observed, and the GaAs solar cells shows relatively larger recovery compared to the 50 QD solar cells. Although the mechanism of this recovery has not yet been clarified, the origin of this recovery is thought not to come from the existence of QDs because the GaAs solar cell without QD layers also shows the recovery.

Oral presentation

Development of seismic assessment method toward the demonstration reactor of JSFR, 1; Project overview and element test

Kitamura, Seiji; Sawa, Naoki*; Iwasaki, Akihisa*; Monde, Masatsugu*; Matsubara, Shinichiro*; Okamura, Shigeki*

no journal, , 

no abstracts in English

Oral presentation

Development of seismic assessment method toward the demonstration reactor of JSFR, 2; Test and analysis of full scale unit

Matsubara, Shinichiro*; Sawa, Naoki*; Iwasaki, Akihisa*; Monde, Masatsugu*; Okamura, Shigeki*; Kitamura, Seiji

no journal, , 

no abstracts in English

Oral presentation

Development of seismic assessment method toward the demonstration reactor of JSFR, 3; Vibration test of 1/1.5 scale test assembly in triangular arrangement

Iwasaki, Akihisa*; Sawa, Naoki*; Monde, Masatsugu*; Matsubara, Shinichiro*; Okamura, Shigeki*; Kitamura, Seiji

no journal, , 

no abstracts in English

Oral presentation

Development of seismic assessment method toward the demonstration reactor of JSFR, 4; Analysis of vibration test of 1/1.5 scale test assembly in triangular arrangement

Monde, Masatsugu*; Sawa, Naoki*; Iwasaki, Akihisa*; Matsubara, Shinichiro*; Okamura, Shigeki*; Kitamura, Seiji

no journal, , 

no abstracts in English

Oral presentation

Radiation degradation of the electrical performance of InGaAs quantum dot solar cells and its recovery at room temperature

Oshima, Takeshi; Sato, Shinichiro; Imaizumi, Mitsuru*; Nakamura, Tetsuya*; Sugaya, Takeyoshi*; Matsubara, Koji*; Niki, Shigeru*

no journal, , 

Oral presentation

Radiation response of fill-factor for GaAs solar cells with InGaAs quantum dot layers

Nakamura, Tetsuya*; Sumita, Taishi*; Imaizumi, Mitsuru*; Sugaya, Takeyoshi*; Matsubara, Koji*; Niki, Shigeru*; Mochizuki, Toru*; Takeda, Akihiro*; Okano, Yoshinobu*; Sato, Shinichiro; et al.

no journal, , 

Radiation effects on GaAs solar cells with InGaAs dot layers were investigated in order to consider the capability of them for space applications. The GaAs solar cells with 50 InGaAs dot layers and also GaAs solar cells with no dot layer were fabricated using a MBE method. They were irradiated with 150 keV-protons at room temperature. As a result, solar cell with dot layers showed higher radiation degradation in short circuit current however, lower degradation in open circuit voltage. Since no significant difference in the degradation of current - voltage characteristics under dark conditions between dot and non-dot solar cells, it is concluded that the degradation of fill fuctor does not come from the degradation of pn diode characteristics but might come from the degradation of minority carrier diffusion length.

Oral presentation

In-situ observation of radiation degradation of GaAs solar cells with InGaAs quantum dot layers

Oshima, Takeshi; Nakamura, Tetsuya*; Sugaya, Takeyoshi*; Sumita, Taishi*; Imaizumi, Mitsuru*; Sato, Shinichiro; Matsubara, Koji*; Niki, Shigeru*; Mochizuki, Toru*; Takeda, Akihiro*; et al.

no journal, , 

Oral presentation

Evaluation of radiation degradation of GaAs solar cells with InGaAs quantum dot layers using radiation induced current

Oshima, Takeshi; Nakamura, Tetsuya*; Sumita, Taishi*; Imaizumi, Mitsuru*; Sato, Shinichiro; Sugaya, Takeyoshi*; Matsubara, Koji*; Niki, Shigeru*; Mochizuki, Toru*; Okano, Yoshinobu*

no journal, , 

Oral presentation

Proton irradiation degradation of GaAs solar cells with InGaAs quantum dot layers

Sato, Shinichiro; Oshima, Takeshi; Nakamura, Tetsuya*; Imaizumi, Mitsuru*; Sugaya, Takeyoshi*; Matsubara, Koji*; Niki, Shigeru*; Takeda, Akihiro*; Okano, Yoshinobu*

no journal, , 

no abstracts in English

Oral presentation

Study of reactor structure for next generation sodium fast reactor; Insertability of core assemblies considering deformation due to irradiation

Matsubara, Shinichiro*; Imaoka, Kengo*; Ikarimoto, Iwao*; Ogawa, Shinta*; Eto, Masao*; Kawasaki, Nobuchika

no journal, , 

Core assemblies installed in the core vessel deform during the normal operation due to swellings and irradiation creep. Insertability of core assemblies during fuel exchanges was studied with consideration of this deformation.

Oral presentation

Core seismic experiment of a full-scale single model for a fast reactor

Iwasaki, Akihisa*; Sawa, Naoki*; Matsubara, Shinichiro*; Kitamura, Seiji; Okamura, Shigeki*

no journal, , 

A fast reactor core consists of several hundred core elements, which are hexagonal flexible beams embedded at the lower support plate in a hexagonal arrangement, separated by small gaps, and immersed in a fluid. Core elements have no support for vertical fixing in order to avoid the influence of thermal expansion and swelling. These days, in Japan, larger earthquake vibrations are postulated in seismic evaluations. So, it is necessary to consider vertical displacements (rising) and horizontal displacements of the core elements simultaneously because vertical seismic vibrations are larger than the acceleration of gravity. The 3D vibration behavior is affected by the fluid force of the ambient coolant and contact with the surrounding core elements. In this study, single-model vibration tests using a full-scale test model were conducted, and the basic characteristics of 3D vibration behavior of the core element were examined. In addition, structures restricting vertical displacements (dashpot structure) were devised, and their effectiveness was verified. As a result of the tests, the effects of the ambient condition (in air, in static water, and in flowing water), gap between the pads, vibration directions, vibration waves, and dashpot structures on the vibration behavior of the core element were examined. As regards the ambient condition, the vertical displacements were larger in flowing water that simulates the coolant flow than in air and in static water, because of upward fluid force in flowing water. As regards the gap between the pads, the larger the gaps was, the stronger the interferences due to horizontal displacements, and the smaller the vertical displacements were. The dashpot structure was verified to be suitable for reducing vertical displacements.

22 (Records 1-20 displayed on this page)