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Numerical simulation of heat transfer behavior in EAGLE ID1 in-pile test using finite volume particle method

Zhang, T.*; 船越 寛司*; Liu, X.*; Liu, W.*; 守田 幸路*; 神山 健司

Annals of Nuclear Energy, 150, p.107856_1 - 107856_10, 2021/01

The EAGLE ID1 test was performed by the Japan Atomic Energy Agency to demonstrate the effectiveness of fuel discharge from a fuel subassembly with an inner duct structure. The experimental results suggested that the early duct wall failure observed in the test was initiated by high heat flux from the molten pool comprising liquid fuel and steel. In addition, the post-test analyses showed that the high heat flux may be enhanced effectively by molten steel in the pool. In this study, a series of thermal-hydraulic behaviors in the ID1 test was analyzed to investigate the mechanisms of molten pool-to-duct wall heat transfer using a fully Lagrangian approach based on the finite volume particle method. The present 2D particle-based simulation demonstrated that a large thermal load on the duct wall can be caused by direct contact of the liquid fuel with nuclear heat and high-temperature liquid steel.


Numerical simulation of the solid particle sedimentation and bed formation behaviors using a hybrid method

Sheikh, M. A. R.*; Liu, X.*; 松元 達也*; 守田 幸路*; Guo, L.*; 鈴木 徹*; 神山 健司

Energies (Internet), 13(19), p.5018_1 - 5018_15, 2020/10

In the safety analysis of sodium-cooled fast reactors, numerical simulations of various thermal-hydraulic phenomena with multicomponent and multiphase flows in core disruptive accidents (CDAs) are regarded as particularly difficult. In the material relocation phase of CDAs, core debris settle down on a core support structure and/or an in-vessel retention device and form a debris bed. The bed's shape is crucial for the subsequent relocation of the molten core and heat removal capability as well as re-criticality. In this study, a hybrid numerical simulation method, coupling the multi-fluid model of the three-dimensional fast reactor safety analysis code SIMMER-IV with the discrete element method (DEM), was applied to analyze the sedimentation and bed formation behaviors of core debris. Three-dimensional simulations were performed and compared with results obtained in a series of particle sedimentation experiments. The present simulation predicts the sedimentation behavior of mixed particles with different properties as well as homogeneous particles. The simulation results on bed shapes and particle distribution in the bed agree well with experimental measurements. They demonstrate the practicality of the present hybrid method to solid particle sedimentation and bed formation behaviors of mixed as well as homogeneous particles.


Production of $$^{266}$$Bh in the $$^{248}$$Cm($$^{23}$$Na,5$$n$$)$$^{266}$$Bh reaction and its decay properties

羽場 宏光*; Fan, F.*; 加治 大哉*; 笠松 良崇*; 菊永 英寿*; 小森 有希子*; 近藤 成美*; 工藤 久昭*; 森本 幸司*; 森田 浩介*; et al.

Physical Review C, 102(2), p.024625_1 - 024625_12, 2020/08


The nuclide $$^{266}$$Bh was produced in the $$^{248}$$Cm($$^{23}$$Na,5n)$$^{266}$$Bh reaction at beam energies of 125.9, 130.6, and 135.3 MeV. Decay properties of $$^{266}$$Bh were investigated with a rotating wheel apparatus for $$alpha$$ and spontaneous fission (SF) spectrometry under low background conditions attained by a gas-jet transport system coupled to the RIKEN gas-filled recoil ion separator. The half-life of $$^{266}$$Bh was measured to be $$T_{rm 1/2}$$ = 10.0$$^{+2.6}_{-1.7}$$ s. The $$alpha$$-particle energies of $$^{266}$$Bh disperse widely in the range of 8.62 - 9.40 MeV. The maximum production cross section for the $$^{248}$$Cm($$^{23}$$Na,5n)$$^{266}$$Bh reaction was determined to be $$sigma$$ = 57 $$pm$$ 14 pb at 130.6 MeV.


Study of quasielastic barrier distributions as a step towards the synthesis of superheavy elements with hot fusion reactions

田中 泰貴*; 森田 浩介*; 森本 幸司*; 加治 大哉*; 羽場 宏光*; Boll, R. A.*; Brewer, N. T.*; Van Cleve, S.*; Dean, D. J.*; 石澤 倫*; et al.

Physical Review Letters, 124(5), p.052502_1 - 052502_6, 2020/02

 被引用回数:0 パーセンタイル:100(Physics, Multidisciplinary)

The excitation functions for quasielastic scattering of $$^{22}$$Ne+$$^{248}$$Cm, $$^{26}$$Mg+$$^{248}$$Cm, $$^{48}$$Ca+$$^{238}$$U are measured using a gas-filled recoil ion separator The quasielastic barrier distributions are extracted for these systems and are compared with coupled-channel calculations. The results indicate that the barrier distribution is affected dominantly by deformation of the actinide target nuclei, but also by vibrational or rotational excitations of the projectile nuclei, as well as neutron transfer processes before capture. From a comparison between the experimental barrier distributions and the evaporation residue cross sections for Sg (Z=106), Hs (108), Cn (112), and Lv (116), it is suggested that the hot fusion reactions take advantage of a compact collision, where the projectile approaches along the short axis of a prolately deformed nucleus. A new method is proposed to estimate the optimum incident energy to synthesize unknown superheavy nuclei using the barrier distribution.


Comparative methodology between actual RCCS and downscaled heat-removal test facility

高松 邦吉; 松元 達也*; Liu, W.*; 守田 幸路*

Annals of Nuclear Energy, 133, p.830 - 836, 2019/11

 被引用回数:0 パーセンタイル:100(Nuclear Science & Technology)



Study on eutectic melting behavior of control rod materials in core disruptive accidents of sodium-cooled fast reactors, 1; Project overview

山野 秀将; 高井 俊秀; 古川 智弘; 菊地 晋; 江村 優軌; 神山 健司; 福山 博之*; 東 英生*; 西 剛史*; 太田 弘道*; et al.

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.418 - 427, 2019/09



Study on eutectic melting behavior of control rod materials in core disruptive accidents of sodium-cooled fast reactors, 5; Validation of a multi-phase model for eutectic reaction between molten stainless steel and B$$_{4}$$C

Liu, X.*; 守田 幸路*; 山野 秀将

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.47 - 51, 2019/09



Observation of the competing fission modes in $$^{178}$$Pt

Tsekhanovich, I.*; Andreyev, A. N.; 西尾 勝久; Denis-Petit, D.*; 廣瀬 健太郎; 牧井 宏之; Matheson, Z.*; 森本 幸司*; 森田 浩介*; Nazarewicz, W.*; et al.

Physics Letters B, 790, p.583 - 588, 2019/03

 被引用回数:8 パーセンタイル:4.7(Astronomy & Astrophysics)

Fragment mass distributions from fission of the excited compound nucleus $$^{178}$$Pt have been deduced from the measured fragment velocities. The $$^{178}$$Pt nucleus was created at the JAEA tandem facility in a complete fusion reaction $$^{36}$$Ar+$$^{142}$$Nd, at beam energies of 155, 170 and 180 MeV. The data are indicative of a mixture of the mass-asymmetric and mass-symmetric fission modes associated with higher and lower total kinetic energies of the fragments, respectively. The measured fragment yields are dominated by asymmetric mass splits, with the symmetric mode contributing at the level of $$approx$$ 1/3. This constitutes the first observation of a multimodal fission in the sub-lead region. Most probable experimental fragment-mass split of the asymmetric mode, $$A_{rm L}$$/$$A_{rm H}$$ $$approx$$ 79/99, is well reproduced by nuclear density functional theory using the UNEDF1-HFB and D1S potentials. The symmetric mode is associated by theory with very elongated fission fragments, which is consistent with the observed total kinetic energy/fragment mass correlation.


Improvement of heat-removal capability using heat conduction on a novel reactor cavity cooling system (RCCS) design with passive safety features through radiation and natural convection

高松 邦吉; 松元 達也*; Liu, W.*; 守田 幸路*

Annals of Nuclear Energy, 122, p.201 - 206, 2018/12

 被引用回数:1 パーセンタイル:73.25(Nuclear Science & Technology)



Experimental study on heat removal performance of a new Reactor Cavity Cooling System (RCCS)

細見 成祐*; 明石 知泰*; 松元 達也*; Liu, W.*; 守田 幸路*; 高松 邦吉

Proceedings of 11th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-11) (Internet), 7 Pages, 2018/11



Validation of three-dimensional finite-volume-particle method for simulation of liquid-liquid mixing flow behavior

加藤 正嗣*; 船越 寛司*; Liu, X.*; 松元 達也*; Liu, W.*; 守田 幸路*; 神山 健司

Proceedings of 11th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-11) (Internet), 7 Pages, 2018/11

Computational fluid dynamics based on particle-based simulations with a fully Lagrangian approach is a powerful tool to understand thermal-hydraulic behaviors of multi-component, multi-phase flows involved in disrupted nuclear core during severe accidents. In this study, a validation study of 3D particle-based simulation using the finite volume particle method was performed for mixing flow behavior of two liquid phases with different densities in a pool. Fundamental experiments using water and silicon oil were also carried out for the present validation. An enhanced multi-phase scheme was introduced to provide accurate and stable calculations of multi-phase flows characterized by high density ratios. The simulation results of the experiments were given to demonstrate validity of the present simulation method and enhanced performance for simulations of mixing and separation behaviors of liquid-liquid two-phase flows in the pool.


Particle-based simulation of heat transfer behavior in EAGLE ID1 in-pile test

守田 幸路*; 小川 竜聖*; 時岡 大海*; Liu, X.*; Liu, W.*; 神山 健司

Proceedings of 12th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, Operation and Safety (NUTHOS-12) (USB Flash Drive), 11 Pages, 2018/10



Numerical simulation on self-leveling behavior of mixed particle beds using multi-fluid model coupled with DEM

Phan, L. H. S.*; 大原 陽平*; 河田 凌*; Liu, X.*; Liu, W.*; 守田 幸路*; Guo, L.*; 神山 健司; 田上 浩孝

Proceedings of 12th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, Operation and Safety (NUTHOS-12) (USB Flash Drive), 12 Pages, 2018/10



Modeling of eutectic reaction between molten stainless steel and B$$_{4}$$C for severe accident simulations

Liu, X.*; 守田 幸路*; 山野 秀将

Proceedings of 12th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, Operation and Safety (NUTHOS-12) (USB Flash Drive), 12 Pages, 2018/10



Sedimentation behavior of mixed solid particles

Sheikh, Md. A. R.*; Son, E.*; 神山 基紀*; 森岡 徹*; 松元 達也*; 守田 幸路*; 松場 賢一; 神山 健司; 鈴木 徹*

Journal of Nuclear Science and Technology, 55(6), p.623 - 633, 2018/06

 被引用回数:4 パーセンタイル:26.29(Nuclear Science & Technology)



First direct mass measurements of nuclides around $$Z$$ = 100 with a multireflection time-of-flight mass spectrograph

伊藤 由太*; Schury, P.*; 和田 道治*; 新井 郁也*; 羽場 宏光*; 平山 賀一*; 石澤 倫*; 加治 大哉*; 木村 創大*; 小浦 寛之; et al.

Physical Review Letters, 120(15), p.152501_1 - 152501_6, 2018/04

 被引用回数:31 パーセンタイル:3.76(Physics, Multidisciplinary)

冷たい核融合反応および熱い融合反応によって生成した変形閉殻中性子数152の近傍に位置する原子核$$^{246}$$Es, $$^{251}$$Fm、および超フェルミウム原子核$$^{249-252}$$Md, $$^{254}$$Noの質量の直接測定を、多反射時間飛行質量分析装置(MR-TOF)を用いて実施した。$$^{246}$$Esおよび$$^{249,250,252}$$Mdの質量測定は世界で初めての成果である。さらに$$^{249,250}$$Mdの質量を$$alpha$$崩壊連鎖のアンカーポイントとして用いて$$^{261}$$Bhおよび$$^{266}$$Mtまでの重い原子核の質量を決定した。これらの新測定された質量を理論質量計算と比較し、巨視的・微視的模型の予測値と良い一致が見られることを示した。近接する3つの質量値から求められる経験的殻ギャップエネルギー$$delta_{2n}$$を今回の質量値から求め、MdおよびLrに対する変形閉殻中性子数$$N=152$$の存在を裏付ける結果を得た。


Model for particle behavior in debris bed

田上 浩孝; Cheng, S.*; 飛田 吉春; 守田 幸路*

Nuclear Engineering and Design, 328, p.95 - 106, 2018/03

 被引用回数:3 パーセンタイル:36.93(Nuclear Science & Technology)

In analyzing the safety of core disruptive accidents in Sodium-cooled Fast Reactors (SFRs), it is important to evaluate whether the decay heat of debris bed can be removed. The decay heat removability changes depending on the shape of debris bed, which would be deformed by coolant vapor with time. In the present paper, a new model was developed to analyze debris bed behavior with SIMMER, which is a safety analysis code for SFRs. In the new model, the effects of inter-particle collisions and contacts are modeled as inter-particle interaction. Test simulation results show the roles of physical properties in the new model on the dense particle behavior. Assessment results of proposed model based on model experiments indicate that the new model is capable of describing the transient of the shape of the particle bed in the liquid driven by the gas phase. Considering the fact that the process of leveling behavior in model experiments is common for the debris bed in SFRs, the new model can be employed as an analysis tool for debris bed behavior.


Experimental study on debris bed characteristics for the sedimentation behavior of solid particles used as simulant debris

Shamsuzzaman, M.*; 堀江 達郎*; 浮池 亮太*; 神山 基紀*; 森岡 徹*; 松元 達也*; 守田 幸路*; 田上 浩孝; 鈴木 徹*; 飛田 吉春

Annals of Nuclear Energy, 111, p.474 - 486, 2018/01

 被引用回数:5 パーセンタイル:18.88(Nuclear Science & Technology)

Particle bed characteristics are experimentally investigated for the sedimentation and subsequent bed formation of solid particles, related to the coolability aspects in core-disruptive accidents. Presently a series of experiments with gravity driven discharge of solid particles into a quiescent water pool was performed to evaluate bed formation characteristic in the course of particle sedimentation. We evaluated the effects of the crucial factors: nozzle diameter, particle density, particle diameter and nozzle height on four key quantitative parameters of bed shape: mound dimple area, mound dimple volume, repose angle and mound height to illustrate the role of the crucial factors on forming the particle bed shape. The investigated crucial factors exhibit a significant role that diversifies the particle bed formation process. Based on the data obtained in the experimental observations, we developed an empirical correlation to compare the predicted results with the experimental bed heights. The proposed empirical correlation can reasonably demonstrate the general trend of the experimental bed height. This correlation could be useful to assess the particle bed elevation, and to identify the governing parameters.


Determination of fusion barrier distributions from quasielastic scattering cross sections towards superheavy nuclei synthesis

田中 泰貴*; 成清 義博*; 森田 浩介*; 藤田 訓裕*; 加治 大哉*; 森本 幸司*; 山木 さやか*; 若林 泰生*; 田中 謙伍*; 武山 美麗*; et al.

Journal of the Physical Society of Japan, 87(1), p.014201_1 - 014201_9, 2018/01

 被引用回数:6 パーセンタイル:33.27(Physics, Multidisciplinary)

ガス充填型反跳生成核分離装置GARISを用いて$$^{48}$$Ca + $$^{208}$$Pb, $$^{50}$$Ti + $$^{208}$$Pb, $$^{48}$$Ca + $$^{248}$$Cm反応系における準弾性散乱断面積の励起関数を測定した。これらのデータから融合障壁分布を導出し、チャンネル結合計算と比較した。$$^{48}$$Ca + $$^{208}$$Pb及び$$^{50}$$Ti + $$^{208}$$Pb反応の障壁分布のピークエネルギーはそれらの反応系における2中性子蒸発断面積のピークエネルギーと良く一致し、一方$$^{48}$$Ca + $$^{248}$$Cm反応の障壁分布のピークエネルギーは4中性子蒸発断面積のピークエネルギーより少し下に現れることが判った。この結果は超重核合成の際の最適ビームエネルギーの予測に役立つ情報を与える。


$$beta$$-delayed fission of $$^{230}$$Am

Wilson, G. L.*; 武山 美麗*; Andreyev, A.; Andel, B.*; Antalic, S.*; Catford, W. N.*; Ghys, L.*; 羽場 宏光*; He${ss}$berger, F. P.*; Huang, M.*; et al.

Physical Review C, 96(4), p.044315_1 - 044315_7, 2017/10

 被引用回数:3 パーセンタイル:55.66(Physics, Nuclear)

The exotic decay process of $$beta$$-delayed fission has been studied in the neutron-deficient isotope $$^{230}$$Am at RIKEN, Japan. The $$^{230}$$Am nuclei were produced in the complete fusion reaction $$^{207}$$Pb($$^{27}$$Al,4n)$$^{230}$$Am and separated by using the GARIS gas-filled recoil ion separator. A lower limit for the $$beta$$-delayed fission probability larger than 0.30 was deduced, which so far is the highest value among all known nuclei exhibiting this decay mode.

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