Study on response correlation during earthquakes using a three-dimensional detailed model and a Sway-Rocking model for nuclear building

Choi, B.; Nishida, Akemi; Takito, Kiyotaka; Tsutsumi, Hideaki*; Takada, Tsuyoshi

Transactions of 27th International Conference on Structural Mechanics in Reactor Technology (SMiRT 27) (Internet), 10 Pages, 2024/03

no abstracts in English

Comparative study on equipment damage correlation during earthquakes using a three-dimensional detailed and a sway-rocking analysis models for nuclear reactor building

Choi, B.; Nishida, Akemi; Takito, Kiyotaka; Tsutsumi, Hideaki*; Takada, Tsuyoshi

Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 8 Pages, 2023/05

no abstracts in English

Predictive modeling of a simple field matrix diffusion experiment addressing radionuclide transport in fractured rock. Is it so straightforward?

Soler, J. M.*; Neretnieks, I.*; Moreno, L.*; Liu, L.*; Meng, S.*; Svensson, U.*; Iraola, A.*; Ebrahimi, K.*; Trinchero, P.*; Molinero, J.*; et al.

Nuclear Technology, 208(6), p.1059 - 1073, 2022/06

https://doi.org/10.1080/00295450.2021.1988822

The SKB Task Force is an international forum on modelling of groundwater flow and solute transport in fractured rock. The WPDE experiments are matrix diffusion experiments in gneiss performed at the ONKALO underground facility in Finland. Synthetic groundwater containing several conservative and sorbing tracers was injected along a borehole interval. The objective of Task 9A was the predictive modelling of the tracer breakthrough curves from the WPDE experiments. Several teams, using different modelling approaches and codes, participated in this exercise. An important conclusion from this exercise is that the modelling results were very sensitive to the magnitude of dispersion in the borehole opening, which is related to the flow of water. Focusing on the tails of the breakthrough curves, which are more directly related to matrix diffusion and sorption, the results from the different teams were more comparable.

A Scaling approach for retention properties of crystalline rock; Case study of the in-situ long-term sorption and diffusion experiment (LTDE-SD) at the sp Hard Rock Laboratory in Sweden

Tachi, Yukio; Ito, Tsuyoshi*; Gylling, B.*

Water Resources Research, 57(11), p.e2020WR029335_1 - e2020WR029335_20, 2021/11

https://doi.org/10.1029/2020WR029335

This paper focuses on the scaling approach for sorption and diffusion parameters from laboratory to in-situ conditions using the dataset of LTDE-SD experiment performed at the sp HRL. The near-surface heterogeneities at both fracture surface and rock matrix could be evaluated by conceptual model with high porosity and diffusivity, and sorption capacity, and their gradual change at the near-surface zones. The modelling results for non-sorbing Cl-36 and weak-sorbing Na-22 could validate the model concept and the parameter estimation of porosity and diffusivity, by considering the disturbed zone of 5 mm thickness with gradual parameter changes. The De values of these cationic and anionic tracers showed typical cation excess and anion exclusion effects. The modelling results for high sorbing tracers (Cs-137, Ra-226, Ni-63 and Np-237) with different sorption mechanism could confirm the validity of the scaling approaches of Kd values as a function of particle size and their relation to the near-surface disturbances.

Hard X-ray photoelectron spectroscopy study of Pt/YFeO

Kobata, Masaaki; Yoshii, Kenji; Fukuda, Tatsuo; Kawasaki, Ikuto; Okane, Tetsuo; Yamagami, Hiroshi; Yaita, Tsuyoshi; Harii, Kazuya; Ieda, Junichi; Okayasu, Satoru; et al.

JPS Conference Proceedings (Internet), 30, p.011192_1 - 011192_6, 2020/03

https://doi.org/10.7566/JPSCP.30.011192

High energy X-ray photoelectron spectroscopy (HAXPES) measurements were carried out for the Spin Seebeck system Pt/YFeO(YIG). This system was found to show anomalous Hall effect, possible due to the formation of intermetallic compounds between Fe and Pt. To reveal this possibility, we have measured the Fe 1s photoelectron peaks by using HAXPES. It was found that the Fe ions consist of Fe in YIG and metallic Fe. The formation of the metallic state is consistent with the proposed origin of the anomalous Hall effect. Other spectra such as Pt 4f will be presented at the conference.

Crack expansion and fracturing mode of hydraulic refracturing from Acoustic Emission monitoring in a small-scale field experiment

Ishida, Tsuyoshi*; Fujito, Wataru*; Yamashita, Hiroto*; Naoi, Makoto*; Fujii, Hirokazu*; Suzuki, Kenichiro*; Matsui, Hiroya

Rock Mechanics and Rock Engineering, 52(2), p.543 - 553, 2019/02

AA2017-0694.pdf:2.54MB

https://doi.org/10.1007/s00603-018-1697-5

We pressurized and injected water in a hole drilled downward from a floor of the 500 m level gallery in MIU, central Japan. Acoustic emissions (AEs) monitored with 16 sensors in four boreholes located 1 m away from the HF hole exhibited two-dimensional distributions, which likely delineate a crack induced by the fracturing. Expansions of the regions in which AEs occurred were observed only immediately after the first and second BDs. Many AE events in other periods were distributed within the regions where AE events had already occurred. The initial motion polarities of P-waves indicate that tensile-dominant AE events occurred when the regions expanded and they were distributed primarily on the frontiers of the regions where AE events had already occurred. The experimental results suggest that increasing the injection flow rate is effective for generating new cracks in the refracturing, with the new crack expansions being induced by tensile fracturing.

Effects of fine-scale surface alterations on tracer retention in a fractured crystalline rock from the Grimsel Test Site

Tachi, Yukio; Ito, Tsuyoshi*; Akagi, Yosuke*; Sato, Hisao*; Martin, A. J.*

Water Resources Research, 54(11), p.9287 - 9305, 2018/11

https://doi.org/10.1029/2018WR023145

Effects of fine-scale surface alterations on radionuclide migration in fractured crystalline rocks were investigated by a comprehensive approach coupling a series of laboratory tests, microscopic observations and modelling, using a single fractured granodiorite sample from the Grimsel Test Site, Switzerland. Laboratory tests including through-diffusion, batch sorption and flow-through tests using five tracers indicated that tracer retention was consistently in the sequence of HDO, Se, Cs, Ni, Eu, and as well as showing the existence of a diffusion-resistance layer near the fracture surface, cation excess and anion exclusion effects for diffusion. Microscale heterogeneities in structural properties around the fracture were clarified quantitatively by coupling X-ray CT and EPMA. A three layer model including weathered vermiculite, foliated mica and undisturbed matrix layers, and their properties such as porosity, sorption and diffusion parameters, could provide a reasonable interpretation for breakthrough curves and concentration distributions near fracture surface of all tracers, measured in flow-through tests.

The Development of method for extinguishing / treating metallic sodium using calcium chloride

Abe, Yuta; Nagai, Keiichi; Maie, Mitsuyoshi*; Nakano, Natsuko*; Kawashima, Yuichi*; Takesue, Naohisa*; Saito, Junichi

Dai-23-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (USB Flash Drive), 5 Pages, 2018/06

no abstracts in English

Space radiation dosimetry to evaluate the effect of polyethylene shielding in the Russian segment of the International Space Station

Nagamatsu, Aiko*; Casolino, M.*; Larsson, O.*; Ito, Tsuyoshi*; Yasuda, Nakahiro*; Kitajo, Keiichi*; Shimada, Ken*; Takeda, Kazuo*; Tsuda, Shuichi; Sato, Tatsuhiko

Physics Procedia, 80, p.25 - 35, 2015/12

https://doi.org/10.1016/j.phpro.2015.11.083

JAXA has been investigated the effect of the shielding material for dosimeters in the ISS Russian segment under the ALTCRISS project. The PADLES package is a passive dosimeters which usually consists of two types of passive and integrating dosimeters, a CR-39 plastic nuclear track detector and a thermoluminescence dosimeter. In the ALTCRISS experiments, both tissue-equivalent material CR-39 PNTDs and NAN-JAERI were enclosed in the PADLES packages as radiators for CR-39 to precisely measure a personal exposed doses. We compared the doses obtained by PADLESs with or without the PEs, and with or difference of the two tissue-equivalent materials. The results of space radiation measurements of the ALTCRISS project Phase 1 to 4 using the PADLES system will be reported in this time: Phase 1 experiments was from December 2005 to April 2006, Phase 2 was from April to September 2006, phase 3 was from Sep 2006 to April 2007, and Phase 4 was conducted from May to October 2007.

Observation of the dependence on the fluence and materials in femto-second laser ablation process by using the soft X-ray laser probe

Hasegawa, Noboru; Tomita, Takuro*; Nishikino, Masaharu; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Minami, Yasuo*; Baba, Motoyoshi*; Onishi, Naofumi*; Ito, Atsushi*; Kawachi, Tetsuya; et al.

JAEA-Conf 2015-001, p.17 - 20, 2015/07

https://jopss.jaea.go.jp/pdfdata/JAEA-Conf-2015-001.pdf#page=27

We have succeeded in simultaneous observation of the ablation front and the expansion front with thin filmy structure in the femto-second laser ablation process of a gold target by using the 13.9 nm soft X-ray probe (incident angle to the sample 70 deg) with soft X-ray interferometer. The dependence on the laser local fluence and materials was obtained by the comparison between gold and tungsten.