A Systematic approach for the adequacy analysis of a set of experimental databases: Application in the framework of the ATRIUM activity

Baccou, J.*; Glantz, T.*; Ghione, A.*; Sargentini, L.*; Fillion, P.*; Damblin, G.*; Sueur, R.*; Iooss, B.*; Fang, J.*; Liu, J.*; et al.

Nuclear Engineering and Design, 421, p.113035_1 - 113035_16, 2024/05

https://doi.org/10.1016/j.nucengdes.2024.113035

In the Best-Estimate Plus Uncertainty (BEPU) framework, the use of best-estimate code requires to go through a Verification, Validation and Uncertainty Quantification process (VVUQ). The relevance of the experimental data in relation to the physical phenomena of interest in the VVUQ process is crucial. Adequacy analysis of selected experimental databases addresses this problem. The outcomes of the analysis can be used to select a subset of relevant experimental data, to encourage designing new experiments or to drop some experiments from a database because of their substantial lack of adequacy. The development of a specific transparent and reproducible approach to analyze the relevance of experimental data for VVUQ still remains open and is the topic of this contribution. In this paper, the concept of adequacy initially introduced in the OECD/NEA SAPIUM (Systematic APproach for model Input Uncertainty quantification Methodology) activity is formalized. It is defined through two key properties, called representativeness and completeness, that allows considering the multifactorial dimension of the adequacy problem. A new systematic approach is then proposed to analyze the adequacy of a set of experimental databases. It relies on the introduction of two sets of criteria to characterize representativeness and completeness and on the use of multi-criteria decision analysis method to perform the analysis. Finally, the approach is applied in the framework of the new OECD/NEA ATRIUM activity which includes a set of practical IUQ exercises in thermal-hydraulics to test the SAPIUM guideline in determining input uncertainties and forward propagating them on an application case. It allows evaluating the adequacy of eight experimental databases coming from the Super Moby-dick, Sozzi-Sutherland and Marviken experiments and identifying the most adequate ones.

Petrophysical properties of representative geological rocks encountered in carbon storage and utilization

Hu, Q.*; Wang, Q. M.*; Zhang, T.*; Zhao, C.*; Iltaf, K. H.*; Liu, S. Q.*; 深津 勇太

Energy Reports (Internet), 9, p.3661 - 3682, 2023/12

https://doi.org/10.1016/j.egyr.2023.02.020

This study evaluates petrophysical properties of representative geological rocks in the context of injectivity, storage space, and caprock integrity for effective utilization and long-term storage of carbon dioxide. A total of 10 geological rocks were selected as representative storage media for consideration as saline aquifers & depleted oil and gas reservoirs, basalts, and cap rocks, as well as utilization in organic-rich shale and coal seams. An integrated suite of laboratory tests, including liquid immersion porosimetry, gas expansion porosimetry, grain size distribution, mercury intrusion porosimetry, and gas diffusion, were performed on these various rock samples. The results exhibit a disparity of petrophysical properties among two broad groups of rocks: rocks selected for possible storage of CO have porosities of 10-25%, permeabilities of 10-10 m, m-sized pore-throat size distribution, and mostly good pore connectivity; in contrast, the potential caprocks have porosities of 0.5-5%, permeabilities of 10-10 m, pore throat sizes of 50 nm, and probably poorly connected pore networks. An understanding of the measured facets of pore structure and contribution of fractures is also critical in the context of different testing principles and data interpretation of petrophysical analyses, as well as observational scales in the laboratory and field, and therefore reliable confidence of CO storage and utilization performance. Our work further illustrates the controlling influence of grain size distribution and geological processes on pore size distribution and pore connectivity for a wide range of rock types and lithologies, and particularly presents the extent and behavior of CO gas diffusion with a custom-designed apparatus for a holistic understanding of various petrophysical attributes of widely different geological rocks.

A Large-scale particle-based simulation of heat and mass transfer behavior in EAGLE ID1 in-pile test

Zhang, T.*; Yao, Y.*; 守田 幸路*; Liu, X.*; Liu, W.*; 今泉 悠也; 神山 健司

Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 9 Pages, 2023/05

The in-pile EAGLE ID1 test was conducted by Japan Atomic Energy Agency to demonstrate the effectiveness of the fuel assembly with an internal duct structure during a core disruptive accident in a sodium-cooled fast reactor. In this study, a new computational fluid dynamics code based on the fully Lagrangian particle method was developed for the purpose of clarifying the failure mechanism of the inner duct wall of FAIDUS. The three-dimensional simulation of the ID1 test was performed to analyze a series of thermal hydraulic behaviors leading up to duct wall failure for a computational domain that included six fuel pins. The simulations reasonably reproduced the heat transfer characteristics observed in the test, showing that the local contact of liquid steel with high thermal conductivity with the duct wall greatly enhances the heat transfer from the nuclear heating fuel to the duct wall. The results support the validity of the conclusions of our analytical study regarding the molten pool-to-duct wall heat transfer mechanism that caused the thermal failure of the duct wall.

Work function lowering of LaB by monolayer hexagonal boron nitride coating for improved photo- and thermionic-cathodes

山口 尚登*; 遊佐 龍之介*; Wang, G.*; Pettes, M. T.*; Liu, F.*; 津田 泰孝; 吉越 章隆; 虻川 匡司*; Moody, N. A.*; 小川 修一*

Applied Physics Letters, 122(14), p.141901_1 - 141901_7, 2023/04

https://doi.org/10.1063/5.0142591

単層BMをコートしたLaBの仕事関数の低減に関して報告する。hBNでコートされた領域は、非被覆あるいはグラフェンコートされたLaB(100)単結晶領域に比べて仕事関数が低下していることが、光電子顕微鏡(PEEM)および熱電子顕微鏡(TEEM)実験から分かった。グラフェンコートに比べてhBNコートされたLaB(100)では、非常に大きな仕事関数の低下が起きることが、DFT計算から定性的に分かった。計算に酸化層を考慮すると、計算と実験の間の整合性が改善された。放射光XPSによって、我々のLaB表面に酸化層が実在することを確認した。

The Experimental and simulation results of LIVE-J2 test; Investigation on heat transfer in a solid-liquid mixture pool

間所 寛; 山下 拓哉; Gaus-Liu, X.*; Cron, T.*; Fluhrer, B.*; 佐藤 一憲; 溝上 伸也*

Nuclear Technology, 209(2), p.144 - 168, 2023/02

https://doi.org/10.1080/00295450.2022.2121545

Since the reactor pressure vessel (RPV) lower head failure determines the subsequent ex-vessel accident progression, it is a key issue to understand the accident progression of Fukushima Daiichi Nuclear Power Station (1F). The RPV failure is largely affected by thermal loads on the vessel wall and thus it is inevitable to understand thermal behavior of molten metallic pool with co- existence of solid oxide fuel debris. In the past decades, numerous experiments have been conducted to investigate a homogeneous molten pool behavior. Few experiments, however, addresses the melting and heat transfer process of debris bed consisted of materials with different melting temperatures. LIVE-J2 experiment aimed to provide the experimental data on a solid-liquid mixture pool in a simulated RPV lower head under various conditions. The extensive measurements of the melt temperature indicate the heat transfer regimes in a solid-liquid mixture pool. The test results showed that the conductive heat transfer was dominant during the steady state along the vessel wall boundary and that convective heat transfer takes place inside the mixture pool. Besides the experimental performance, the test case was numerically simulated by using ANSYS Fluent. The simulation results generally agree with the measured experimental data. The flow regime and transient melt evolution were able to be estimated by the calculated velocity field and the crust thickness, respectively.

"Southwestern" boundary of the island of inversion; First study of low-lying bound excited states in V and V

Elekes, Z.*; Juhsz, M. M.*; Sohler, D.*; Sieja, K.*; 吉田 数貴; 緒方 一介*; Doornenbal, P.*; Obertelli, A.*; Achouri, N. L.*; 馬場 秀忠*; et al.

Physical Review C, 106(6), p.064321_1 - 064321_10, 2022/12

https://doi.org/10.1103/PhysRevC.106.064321

VとVの低励起準位構造を初めて探索した。Vについては中性子ノックアウト反応と陽子非弾性散乱が、Vについては中性子ノックアウト反応データが得られた。Vについては4つ、Vについては5つの新たな遷移が確認された。Lenzi-Nowacki-Poves-Sieja (LNPS)相互作用に基づく殻模型計算との比較によって、それぞれの同位体について確認されたガンマ線のうち3つが、first 11/2状態とfirst 9/2状態からの崩壊と決定された。Vについては、(,)非弾性散乱断面積は四重極変形と十六重極変形を想定したチャネル結合法により解析されたが、十六重極変形の影響により、明確に反転の島に属するとは決定できなかった。

Spin fluctuations in the 112-type iron-based superconductor CaLaFeNiAs

Xie, T.*; Liu, C.*; 梶本 亮一; 池内 和彦*; Li, S.*; Luo, H.*

Journal of Physics; Condensed Matter, 34(47), p.474001_1 - 474001_8, 2022/11

https://doi.org/10.1088/1361-648X/ac9441

We report time-of-flight inelastic neutron scattering (INS) investigations on the spin fluctuation spectrum in the 112-type iron-based superconductor (FeSC) CaLaFeNiAs (CaLa-112). In comparison to the 122-type FeSCs with a centrosymmetric tetragonal lattice structure (space group ) at room temperature and an in-plane stripe-type antiferromagnetic (AF) order at low temperature, the 112 system has a noncentrosymmetric structure (space group ) with additional zigzag arsenic chains between Ca/La layers and a magnetic ground state with similar wavevector but different orientations of ordered moments in the parent compounds. Our INS study clearly reveals that the in-plane dispersions and the bandwidth of spin excitations in the superconducting CaLa-112 closely resemble to those in 122 systems. While the total fluctuating moments /Fe are larger than 122 system, the dynamic correlation lengths are similar ( ). These results suggest that superconductivity in iron arsenides may have a common magnetic origin under similar magnetic exchange couplings with a dual nature from local moments and itinerant electrons, despite their different magnetic patterns and lattice symmetries.

Laser stripping for 1.3 GeV H beam at the SNS

Gorlov, T.*; Aleksandrov, A.*; Cousineau, S.*; Liu, Y.*; Oguz, A. R.*; Kay, M.*; Saha, P. K.

Proceedings of the 2022 North American Particle Accelerator Conference (NAPAC 2022) (Internet), p.702 - 704, 2022/08

https://doi.org/10.18429/JACoW-NAPAC2022-WEPA33

The conventional method of H charge-exchange injection by using a solid stripper foil has serious drawbacks such as, a short foil lifetime, unexpected failure and moreover a high residual radiation due to uncontrolled foil scattering beam losses at high-intensity operation. To overcome all those issues, an H stripping by using only lasers or by laser assisted are being extensively studied at J-PARC and the Spallation Neutron Source (SNS) at Oak Ridge, USA, respectively. However, a reduction of the laser power to realize the laser stripping is a common issue at both labs. In this research, different schemes and methods of laser stripping, especially for an effective excitation of the ground state hydrogen atom are considered. Among all methods the most realistic and practical scheme seems to be the sequential excitation scheme by using two types of laser. In this case, a laser power can be reduced to 1/25 as compared to a single step excitation. Due to a lower H energy, a deep UV laser is used at J-PARC. Such a reduction of the laser power is further useful for a realistic implementation.

LIVE-J1 experiment on debris melting behavior toward understanding late in-vessel accident progression of the Fukushima Daiichi Nuclear Power Station

間所 寛; 山下 拓哉; 佐藤 一憲; Gaus-Liu, X.*; Cron, T.*; Fluhrer, B.*; Stngle, R.*; Wenz, T.*; Vervoortz, M.*; 溝上 伸也

Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 16 Pages, 2022/03

Debris and molten pool behavior in the reactor pressure vessel (RPV) lower plenum is a key factor to determine its failure mode, which affects the initial condition of ex-vessel accident progression and the debris characteristics. These are necessary information to accomplish safe decommissioning of the Fukushima Daiichi Nuclear Power Station. After dryout of the solidified debris in the lower plenum, metallic debris is expected to melt prior to the oxide debris due to its lower melting temperature. The lower head failure is likely be originated by the local thermal load attack of a melting debris bed. Numerous experiments have been conducted in the past decades to investigate the homogeneous molten pool behavior with external cooling. However, few experiments address the transient heat transfer of solid-liquid mixture without external cooling. In order to enrich the experimental database of melting and heat transfer process of debris bed consisted of materials with different melting temperatures, LIVE-J1 experiment was conducted using ceramic and nitrate particles as high melting and low melting temperature simulant materials, respectively. The test results showed that debris height decreased gradually as the nitrate particles melt, and molten zone and thermal load on vessel wall were shifted from bottom upwards. Both conductive and convective heat transfer could take place in a solid-liquid mixture pool. These results can support the information from the internal investigations of the primary containment vessel and deepen the understanding of the accident progression.

Investigation of the ground-state spin inversion in the neutron-rich Cl isotopes

Linh, B. D.*; Corsi, A.*; Gillibert, A.*; Obertelli, A.*; Doornenbal, P.*; Barbieri, C.*; Chen, S.*; Chung, L. X.*; Duguet, T.*; Gmez-Ramos, M.*; et al.

Physical Review C, 104(4), p.044331_1 - 044331_16, 2021/10

AA2021-0468.pdf:1.29MB

https://doi.org/10.1103/PhysRevC.104.044331

理化学研究所のRIビームファクトリーにて中性子過剰Clの励起状態をArからのノックアウト反応によって生成し、脱励起ガンマ線からそのエネルギー準位を測定した。また、陽子ノックアウトの運動量分布からClの基底状態がであることがわかった。その結果を大規模殻模型計算およびいくつかの第一原理計算と比較した。Cl同位体の基底状態および第一励起状態は、計算で用いた相互作用に敏感であることがわかった。それは、陽子の一粒子エネルギーと四重極集団運動との複雑な結合によるためであると考えられる。