Large-eddy simulation on two-liquid mixing in the horizontal leg and downcomer (the TAMU-CFD Benchmark), with respect to fluctuation behavior of liquid concentration

安部 諭; 岡垣 百合亜

Nuclear Engineering and Design, 404, p.112165_1 - 112165_14, 2023/04

https://doi.org/10.1016/j.nucengdes.2023.112165

Pressurized Thermal Shock (PTS) is induced potentially by the rapid cooling of the cold-leg and downcomer wall in the primary system of a Pressurized Water Reactor (PWR) due to the initiation of Emergency Core Cooling System (ECCS). Thus, fluids mixing in a horizontal cold-leg and downcomer should be predicted accurately; however, turbulence production and damping often hinders this prediction due to the presence of the density gradients. Hence, the Fifth International Benchmark Exercise, the cold-leg mixing Computational Fluid Dynamics (CFD) Benchmark, was conducted under the support of OECD/NEA. The experiment was designed for visualization of the mixing phenomena of two liquids with different densities. The heavy liquid was a simulant of cold water from ECCS, in a horizontal leg and downcomer. We used the Large-eddy Simulation (LES) to investigate the time fluctuation behaviors of velocity and liquid concentration. The CFD simulation was performed with two turbulence models and three different numerical meshes. We investigated the characteristics of the appearance frequency of the heavy liquid concentration with the statistical method. Based on our findings, we propose further experiments and numerical investigations to understand the fluid mixing phenomena related to PTS.

連続エネルギーモンテカルロコードMVPとJENDL-5によるTRIGA型原子炉体系の臨界ベンチマーク解析

柳澤 宏司; 梅田 幹; 求 惟子; 村尾 裕之

JAEA-Technology 2022-030, 80 Pages, 2023/02

JAEA-Technology-2022-030.pdf:2.57MB
JAEA-Technology-2022-030(errata).pdf:0.11MB

連続エネルギーモンテカルロコードMVPと評価済み核データライブラリJENDL-5によって、ウラン水素化ジルコニウム燃料棒を用いるTRIGA型原子炉体系の臨界ベンチマーク解析を行った。解析対象は、国際臨界安全ベンチマークプロジェクト(ICSBEP)のハンドブックに掲載されているIEU-COMP-THERM-003とIEU-COMP-THERM-013の二種類のデータであり、中性子実効増倍率、制御棒等の反応度価値について旧バーションのJENDLを使用した結果と比較した。その結果、JENDL-5による中性子実効増倍率はJENDL-4.0よりも0.4から0.6%大きく、制御棒等の反応度価値は、JENDL-5とJENDL-4.0との有意な差は無いことが分かった。これらの解析結果は今後予定しているNSRRの制御棒反応度価値等の解析において、計算精度の確認の参考になるものと考えられる。

Nuclear data processing code FRENDY; A Verification with HTTR criticality benchmark experiments

藤本 望*; 多田 健一; Ho, H. Q.; 濱本 真平; 長住 達; 石塚 悦男

Annals of Nuclear Energy, 158, p.108270_1 - 108270_8, 2021/08

https://doi.org/10.1016/j.anucene.2021.108270

Japan Atomic Energy Agency has developed a new nuclear data processing code, namely FRENDY, to generate the ACE files from various nuclear libraries. A code-to-experiment verification of FRENDY processing was carried out in this study with criticality benchmark assessments of the high temperature engineering test reactor. The ACE files of the JENDL-4.0 and ENDF-B-VII.1 was generated successfully by FRENDY. These ACE files have been used in MCNP6 transportation calculation for various benchmark problems of the high temperature engineering test reactor. As a result, the k and reaction rate obtained by MCNP6 calculation presented a good agreement compared to the experimental data. The proper ACE files generation by FRENDY was confirmed for the HTTR criticality calculations.

Special issue on accelerator-driven system benchmarks at Kyoto University Critical Assembly

Pyeon, C. H.*; Talamo, A.*; 福島 昌宏

Journal of Nuclear Science and Technology, 57(2), p.133 - 135, 2020/02

https://doi.org/10.1080/00223131.2019.1680324

The accelerator-driven system (ADS) had been proposed for producing energy and transmuting minor actinide and long-lived fission products. ADS has attracted worldwide attention in recent years because of its superior safety characteristics and potential for burning plutonium and nuclear waste. At the Institute for Integrated Radiation and Nuclear Science, Kyoto University, a series of ADS experiments with 14 MeV neutrons was launched in fiscal year 2003 at the Kyoto University Critical Assembly (KUCA). Also, the high-energy neutrons generated by the interaction of 100 MeV protons with tungsten target was injected into the KUCA core on March 2009. The ADS experiments with 100 MeV protons obtained from the FFAG accelerator have been carried out to investigate the neutron characteristics of ADS. This special issue aims at concentrating on experimental analyses for the ADS benchmarks at KUCA on the basis of most recent advances in the development of computational methods, and contributing to academic progress for ADS research field in the future.

Benchmark of fuel performance codes for FeCrAl cladding behavior analysis

Pastore, G.*; Gamble, K. A.*; Cherubini, M.*; Giovedi, C.*; Marino, A.*; 山路 哲史*; 加治 芳行; Van Uffelen, P.*; Veshchunov, M.*

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.1038 - 1047, 2019/09

耐酸化性FeCrAl鋼が軽水炉の事故耐性燃料用被覆管として提案されている。IAEAの研究プロジェクトの一環として、FeCrAl被覆管挙動に関する燃料ふるまいモデリングのベンチマークを実施した。この中で、FeCrAl被覆管材料の燃料棒問題に対して種々の燃料ふるまいコードを用いて計算を行い結果を相互に比較した。

Stratification break-up by a diffuse buoyant jet; A CFD benchmark exercise

Studer, E.*; 安部 諭; Andreani, M.*; Bharj, J. S.*; Gera, B.*; Ishay, L.*; Kelm, S.*; Kim, J.*; Lu, Y.*; Paliwal, P.*; et al.

Proceedings of 12th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, Operation and Safety (NUTHOS-12) (USB Flash Drive), 16 Pages, 2018/10

Nuclear engineering research groups were interested in the phenomena of the interaction between a rising jet and a stratified layer located above in order to better understand the underlying mechanisms of hydrogen accumulation and dispersion in a nuclear reactor containment. Previous studies were performed with an upward jet of fluid heavier or lighter than the upper stratified layer. However, in real configurations i.e. the inner part of a nuclear containment, obstacles such as pipes, components as pumps or reservoirs and walls are present, and they can dissipate the initial momentum of the gas release. Consequently, the upward flow pattern can be considered "diffuse" and buoyant, neither pure jet nor pure plume. Therefore, this challenging issue was part of a project called HYMERES, which was launched and conducted in the OECD/NEA framework. Dedicated experiments were performed to study the interaction between a diffuse buoyant jet and two-layer stratification. In the large-scale MISTRA facility, the HM1-1 test series were conducted in which the erosive flow pattern came from a horizontal hot air jet impinging on a vertical cylinder. These experimental results were offered for a blind and open benchmark exercise.

Analyses with latest major nuclear data libraries of the fission rate ratios for several TRU nuclides in the FCA-IX experiments

福島 昌宏; 辻本 和文; 岡嶋 成晃

Journal of Nuclear Science and Technology, 54(7), p.795 - 805, 2017/07

https://doi.org/10.1080/00223131.2017.1299644

FCAの複数の系統的に異なる中性子スペクトル場における7つのTRU核種(Np, Pu, Pu, Pu, Am, Am, Cm)の核分裂率比に関するベンチマークモデルを用いて、主要な核データライブラリ(JENDL-4.0, ENDF/B-VII.1, JEFF-3.2)に対する積分評価を行ったものである。いずれの主要核データライブラリによる解析値は、Cm対Pu核分裂比を大幅に過大評価することが示された。また、中間エネルギーの中性子スペクトル場におけるPu対Pu核分裂比に関して、核データ間で有意な差異があることが示され、感度解析によりこの原因について調査を行った。

Comparative study on burnup characteristics of a 1500 MWe metal fuel sodium-cooled fast reactor

大釜 和也; Aliberti, G.*; Stauff, N. E.*; 大木 繁夫; Kim, T. K.*

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 8 Pages, 2017/04

Under the cooperative effort of the Civil Nuclear Energy R&D Working Group within the framework of the U.S.-Japan bilateral, Argonne National Laboratory (ANL) and Japan Atomic Energy Agency (JAEA) have been performing benchmark study using the Japan Sodium-cooled Fast Reactor (JSFR) design with metal fuel. In this benchmark study, the atomic number densities and core characteristics at the end of cycle were evaluated by the best estimate deterministic methodologies of ANL and JAEA. The atomic number densities of plutonium isotopes calculated by both institutions showed a good agreement with less than 0.5% of discrepancy, except for the atomic number density of Pu-241. The atomic number densities of americium and curium isotopes showed less than 6% of discrepancy. The results of core characteristics at the end of cycle obtained by both institutions showed a reasonably good agreement with less than 400 pcm of discrepancy on the neutron multiplication factor, and less than 3% of discrepancy on the sodium void reactivity, Doppler reactivity, and control rod worth. A burnup sensitivity analysis was employed to identify the major factors of the difference in the calculated atomic number densities at the end of cycle.

Comparative study on neutronics characteristics of a 1500 MWe metal fuel sodium-cooled fast reactor

大釜 和也; Aliberti, G.*; Stauff, N. E.*; 大木 繁夫; Kim, T. K.*

Proceedings of 24th International Conference on Nuclear Engineering (ICONE-24) (DVD-ROM), 6 Pages, 2016/06

https://doi.org/10.1115/ICONE24-60455

日米二国間協力枠組による民生原子力研究開発ワーキンググループにおける国際協力の下、アルゴンヌ国立研究所(ANL)および原子力機構は、JSFR金属燃料炉心のベンチマーク研究を実施してきている。このベンチマーク研究では、ANLおよび原子力機構の決定論最確評価手法およびモンテカルロ法により、平衡サイクル初期の炉心核特性を評価した。ANLおよび原子力機構の解析結果は、中性子増倍率において200pcm以下の差で、ナトリウムボイド反応度、ドップラ係数および制御棒価値において3%以下でよく一致した。決定論による近似の影響を分析するとともに、解析手法の違いによる結果への影響を把握するため、決定論およびモンテカルロ法の計算結果を比較した。また、核データライブラリの違いによる影響を感度解析法により分析した。

Proceedings of the 2014 Symposium on Nuclear Data; November 27-28, 2014, Conference hall, Hokkaido University, Sapporo Japan

合川 正幸*; 岩本 修; 江幡 修一郎*; 国枝 賢; 中村 詔司; 小浦 寛之

JAEA-Conf 2015-003, 332 Pages, 2016/03

JAEA-Conf-2015-003.pdf:30.22MB

2014年度核データ研究会は、2014年11月27日28日に、北海道札幌市の北海道大学学術交流会館にて開催された。本研究会は、日本原子力学会核データ部会、日本原子力学会北海道支部、北海道大学大学院理学研究院原子核反応データベース研究開発センターが主催、日本原子力研究開発機構原子力基礎工学研究センターが共催した。今回、チュートリアルとして「長寿命核分裂生成物の核変換データとその戦略」、「がん放射線治療に必要な物理と核データ」の2件を、講演・議論のセッションとして「核データコミュニティーが望む中性子飛行時間法測定装置」、「最近のトピックス」、「核データの利用」、「核理論と核データ」の4件を企画・実施した。さらに、ポスターセッションでは、実験、評価、ベンチマーク、応用など、幅広い研究内容について発表が行われた。参加者総数は88名で、それぞれの口頭発表及びポスター発表では活発な質疑応答が行われた。本報告書は、本研究会におけるチュートリアル2件、口頭発表16件、ポスター44件の論文をまとめてある。