Stress corrosion cracking induced by the combination of external and internal hydrogen in Al-Zn-Mg-Cu alloy

Tang, J.*; Wang, Y.*; Fujihara, Hiro*; Shimizu, Kazuyuki*; Hirayama, Kyosuke*; Ebihara, Kenichi; Takeuchi, Akihisa*; Uesugi, Masayuki*; Toda, Hiroyuki*

Scripta Materialia, 239, p.115804_1 - 115804_5, 2024/01

https://doi.org/10.1016/j.scriptamat.2023.115804

Stress corrosion cracking (SCC) behaviors induced by the combination of external and internal hydrogen (H) in an Al-Zn-Mg-Cu alloy were systematically investigated via in situ 3D characterization techniques. SCC of the Al-Zn-Mg-Cu alloy could initiate and propagate in the potential crack region where the H concentration exceeded a critical value, in which the nanoscopic H-induced decohesion of -MgZn precipitates resulted in macroscopic cracking. External H that penetrated the alloy from the environment played a crucial role during the SCC of the Al-Zn-Mg-Cu alloy by generating gradient-distributed H-affected zones near the crack tips, which made Al alloys in water environment more sensitive to SCC. Additionally, the pre-existing internal H was driven toward the crack tips during plastic deformation. It was involved in the SCC and made contributions to both the cracks initiation and propagation.

Development of three-dimensional distribution visualization technology for boron using energy resolved neutron-imaging system (RADEN)

Abe, Yuta; Tsuchikawa, Yusuke; Kai, Tetsuya; Matsumoto, Yoshihiro*; Parker, J. D.*; Shinohara, Takenao; Oishi, Yuji*; Kamiyama, Takashi*; Nagae, Yuji; Sato, Ikken

Proceedings of 2020 International Conference on Nuclear Engineering (ICONE 2020) (Internet), 6 Pages, 2020/08

https://doi.org/10.1115/ICONE2020-16723

Evaluation of the excavation disturbed zone of sedimentary rock in the Horonobe Underground Research Laboratory

Kubota, Kenji*; Aoyagi, Kazuhei; Sugita, Yutaka

Proceedings of 2019 Rock Dynamics Summit in Okinawa (USB Flash Drive), p.729 - 733, 2019/05

During the excavation of shafts and galleries in the deep subsurface for disposing of high-level radioactive waste, an excavation disturbed zone (EdZ) or excavation damaged zone (EDZ) is developed around the shafts and galleries. Such zones could influence the transfer behavior of radioactive nuclides, and it is therefore important to understand the behavior of the EdZ or EDZ. We performed in situ experiments before, during, and after gallery excavation in galleries of 140 and 250 m in depth in an area of soft sedimentary rock in Japan. The results demonstrate that the extent of fractures induced by the gallery excavation related with EDZ was confined to about 0.45 m from the gallery wall in the 140 m gallery and to about 1 m from the gallery wall in the 250 m gallery. The extent of the unsaturated zone related with EdZ was about 1 m in the 140 m gallery, but an unsaturated zone did not appear in the 250 m gallery.

Investigation of the excavation disturbed zone due to the excavation of horizontal galleries; Study in the Horonobe Underground Research Laboratory

Kubota, Kenji*; Aoyagi, Kazuhei; Sugita, Yutaka

Koeki Shadan Hojin Butsuri Tansa Gakkai Dai-138-Kai (Heisei-30-Nendo Shuki) Gakujutsu Koenkai Koen Rombunshu, p.51 - 54, 2018/05

In an excavation of shafts and galleries in the deep underground for disposing high level radioactive waste, an excavation disturbed zone (EdZ) or excavation damaged zone (EDZ) is developed around the shafts and galleries owing to the stress redistribution. It is important to understand the behavior of the EdZ or EDZ because these zone could have an effect on the transfer behavior of radioactive nuclide. Therefore, the authors performed the in situ experiment to investigate the behavior of EdZ or EDZ in the 140m and 250m gallery in the Horonobe Underground Research Laboratory. From the result of the experiments, the authors compared the characteristics of EdZ or EDZ between those in 140m and 250m gallery. The extent of the fractures induced by the gallery excavation, i.e., EDZ was about 0.45m in the 140m gallery and about 1m in the 250m gallery. The extent of the unsaturated zones related with EdZ was about 1m in the 140m gallery, however, unsaturated zone was not appeared in the 250m gallery.

Visualization of boiling two-phase flow in a tight-lattice 14-rod bandle

Kureta, Masatoshi

Kashika Joho Gakkai-Shi, 24(Suppl.1), p.265 - 268, 2004/07

http://doi.org/10.3154/jvs.24.Supplement1_265

Visualization of 3D and instantaneous void fraction distribution of boiling flow in a tight-lattice 14-rod bundle is conducted by using neutron tomography and high-frame- rate neutron radiography void fraction measurement techniques. The purpose of the experiment is to understand vapor bubbles/water behavior ranging from the onset of boiling to the high void fraction region based on ("3D" + "2D+Time") void fraction data, and to obtain the fine-mesh database for verification of advanced analysis codes. Following phenomena are made clear from the present experiment: Vapor accumulates in the channel center; High void fraction spots appear between adjacent heater rods, that is, in narrow space at the inlet; Void fraction in the triangular space among three rods becomes high by void drift phenomenon, and "vapor chimney" is formed; Flow is intermittent, and vapor bubble clusters are formed periodically; Onset points of net vapor generation are scattered not only in the center but in the peripheral.

Visualization and measurement of boiling flow using neutron beam

Kureta, Masatoshi; Hoshi, Yoshiyuki; Yamada, Kazuyuki*; Sakamoto, Kiyotaka*

Nikkei Saiensu, 111 Pages, 2004/01

no abstracts in English

Study on deep groundwater flow

Kumata, Masahiro; Mukai, Masayuki; Iwamoto, Hiroshi*

JAERI-Conf 2001-015, p.80 - 81, 2001/12

https://jopss.jaea.go.jp/pdfdata/JAERI-Conf-2001-015.pdf

Based on the groundwater scenario, prediction of the transport of radionuclides from waste disposal facilities requires an understanding of deep groundwater flow system. Capabilities offering by isotope techniques using environmental tracer enable one to estimate past and present behavior of groundwater system, and therefore establish a basis for future predictions. A study area was selected in Japan and hydrogeological study has been performed. On the other hand, fractures in the hard rock mass play an important role on groundwater flow at the depth. Basic study was performed for resistivity tomography, one of the useful techniques for the evaluation of rock fractures.

Observation of detachment in the JET MkIIGB divertor usig CCD camera tomography

Itami, Kiyoshi; Coad, P.*; Fundamenski, W.*; Ingesson, C.*; Lingertat, J.*; Matthews, G. F.*; Tabasso, A.*

Journal of Nuclear Materials, 290-293, p.633 - 638, 2001/03

https://doi.org/10.1016/S0022-3115(00)00520-1

no abstracts in English

Visualization of water movement in the vicinity of plant root by neutron beam

Furukawa, Jun*; Nakanishi, Tomoko*; Matsubayashi, Masahito

Kashika Joho Gakkai-Shi, 20(suppl.1), p.377 - 380, 2000/07

no abstracts in English

Analysis of hydrogen content and distribution in hydrogen storage alloys using neutron radiography

Sakaguchi, Hiroki*; Hatakeyama, Keisuke*; Satake, Yuichi*; Fujine, Shigenori*; Yoneda, Kenji*; Kanda, Keiji*; Matsubayashi, Masahito; Esaka, Takao*

Kashika Joho Gakkai-Shi, 20(suppl.1), p.373 - 374, 2000/07

no abstracts in English