Identification of hydrogen trapping in aluminum alloys muon spin relaxation method and first-principles calculations

Tsuru, Tomohito; Nishimura, Katsuhiko*; Matsuda, Kenji*; Nunomura, Norio*; Namiki, Takahiro*; Lee, S.*; Higemoto, Wataru; Matsuzaki, Teiichiro*; Yamaguchi, Masatake; Ebihara, Kenichi; et al.

Metallurgical and Materials Transactions A, 54(6), p.2374 - 2383, 2023/06

https://doi.org/10.1007/s11661-023-07024-w

Although hydrogen embrittlement susceptibility of high-strength Al alloys is recognized as a critical issue in the practical use of Al alloys, identifying the hydrogen trapping or distribution has been challenging. In the present study, an effective approach based on experiment and simulation is proposed to explore the potential trap sites in Al alloys. Zero-field muon spin relaxation experiments were carried out for Al-0.5%Mg, Al-0.2%Cu, Al-0.15%Ti, Al-0.011%Ti, Al-0.28%V, and Al-0.015%V (at.%) in the temperature range from 5 to 300 K. The temperature variations of the dipole field widths have revealed three peaks for Al-0.5%Mg, four peaks for Al-0.2%Cu, three peaks for Al-0.011%Ti and Al-0.015%V. Atomic configurations of the muon trapping sites corresponding to the observed peaks are well assigned using the first-principles calculations for the trap energies of hydrogen around a solute and solute-vacancy pair. The extracted linear relationship between the muon peak temperature and the trap energy enables us to explore the potential alloying elements and their complex that have strong binding energies with hydrogen in Al alloys.

Practical guide on soil sampling, treatment, and carbon isotope analysis for carbon cycle studies

Koarashi, Jun; Atarashi-Andoh, Mariko; Nagano, Hirohiko*; Sugiharto, U.*; Saengkorakot, C.*; Suzuki, Takashi; Kokubu, Yoko; Fujita, Natsuko; Kinoshita, Naoki; Nagai, Haruyasu; et al.

JAEA-Technology 2020-012, 53 Pages, 2020/10

JAEA-Technology-2020-012.pdf:3.71MB

There is growing concern that recent rapid changes in climate and environment could have a significant influence on carbon cycling in terrestrial ecosystems (especially forest ecosystems) and could consequently lead to a positive feedback for global warming. The magnitude and timing of this feedback remain highly uncertain largely due to a lack of quantitative understanding of the dynamics of organic carbon stored in soils and its responses to changes in climate and environment. The tracing of radiocarbon (natural and bomb-derived C) and stable carbon (C) isotopes through terrestrial ecosystems can be a powerful tool for studying soil organic carbon (SOC) dynamics. The primary aim of this guide is to promote the use of isotope-based approaches to improve our understanding of the carbon cycling in soils, particularly in the Asian region. The guide covers practical methods of soil sampling; treatment and fractionation of soil samples; preparation of soil samples for C (and stable nitrogen isotope, N) and C analyses; and C, N, and C measurements by the use of isotope ratio mass spectrometry and accelerator mass spectrometry (AMS). The guide briefly introduces ways to report C data, which are frequently used for soil carbon cycling studies. The guide also reports results of a case study conducted in a Japanese forest ecosystem, as a practical application of the use of isotope-based approaches. This guide is mainly intended for researchers who are interested but are not experienced in this research field. The guide will hopefully encourage readers to participate in soil carbon cycling studies, including field works, laboratory experiments, isotope analyses, and discussions with great interest.

Grain size dependence of meteoric Be concentrations in bed-sediments of Ado and Yasu rivers flowing into Lake Biwa

Fujisawa, Jumpei*; Minami, Masayo*; Kokubu, Yoko; Matsuzaki, Hiroyuki*

JAEA-Conf 2018-002, p.91 - 94, 2019/02

https://doi.org/10.11484/jaea-conf-2018-002

Beryllium-10 (Be) of a cosmogenic nuclide precipitates in forms of BeO and Be(OH) attaching with aerosol on the Earth surface. It is accumulated on the sea- and lake-bottoms. Recently, the meteoric Be is attracting attention as a powerful tool for investigating the past climate change, because it is affected by the earth- and lorcal- cyclical changes of materials such as atmosphere and water circulation. The Be exists mostly as hydroxide at pH 5, and is easy to adhere to soil and mineral surface. Therefore, Be concentration in sediment could be influenced by its grain size composition because fine-grained sediment has a big surface area per unit mass. The purpose of this study is to reveal the relationship between Be concentrations and the grain-size of river sediments. The samples used were bottom-sediments of 18 rivers flowing into Lake Biwa, Japan. The sediments were sieved to 5 fractions and analyzed each for Be concentration by JAEA-AMS-TONO.

Age and speciation of iodine in groundwater and mudstones of the Horonobe area, Hokkaido, Japan; Implications for the origin and migration of iodine during basin evolution

Togo, Yoko*; Takahashi, Yoshio*; Amano, Yuki; Matsuzaki, Hiroyuki*; Suzuki, Yohei*; Terada, Yasuko*; Muramatsu, Yasuyuki*; Ito, Kazumasa*; Iwatsuki, Teruki

Geochimica et Cosmochimica Acta, 191, p.165 - 186, 2016/10

https://doi.org/10.1016/j.gca.2016.07.012

Iodine distribution, speciation, and isotope ratio (I/I) in both rock and groundwater phases were determined to investigate long-term migration of iodine in diatomaceous and siliceous shale. It was suggested that I is released to the ground water during the progress of the maturation of organic matter. Dissociated I could move toward the surface because of the upward water flow driven by the compaction during burial diagenetic process. Thus, iodine rich brine is created by integration of iodine released from underlying formations. Because of low affinity of I to solid phase, released I remains in solution phase, and the concentration of the iodine in the solution has been possibly increasing during sedimentation history.

Utilization status of the electron accelerator and the -ray irradiation facilities

Agematsu, Takashi; Hanaya, Hiroaki; Yamagata, Ryohei; Seito, Hajime; Nagao, Yuto; Kaneko, Hirohisa; Yamaguchi, Toshiyuki*; Kawashima, Ikuo*; Yagi, Norihiko*; Takagi, Masahide*; et al.

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 183, 2015/03

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2014-050.pdf#page=215

https://doi.org/10.11484/jaea-review-2014-050

The electron accelerator and the three -ray irradiation facilities were operated for various research subjects according to the operation plan in FY 2013. The number of research subjects at the electron accelerator and at the -ray irradiation facilities kept constant from FY 2012. Among these research subjects, 47 and 91 ones respectively performed at the electron accelerator and the -ray irradiation facilities were relevant to recovery from the Fukushima Daiichi nuclear disaster.

Utilization status of the electron accelerator and the -ray irradiation facilities

Agematsu, Takashi; Haruyama, Yasuyuki; Hanaya, Hiroaki; Yamagata, Ryohei; Seito, Hajime; Nagao, Yuto; Kaneko, Hirohisa; Yamaguchi, Toshiyuki*; Yagi, Norihiko*; Takagi, Masahide*; et al.

JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 181, 2014/03

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2013-059.pdf

The electron accelerator and the three -ray irradiation facilities were operated for various research subjects according to the operation plan in FY 2012. The number of research subjects at the electron accelerator kept constant compared with FY 2011. The number of research subjects at the -ray irradiation facilities slightly decreased year after year. Of all these research subjects, 14 ones at the electron accelerator and 93 ones at the -ray irradiation facilities were relevant to the Fukushima Daiichi nuclear disaster.

Operation of the electron accelerator and the -ray irradiation facilities

Agematsu, Takashi; Haruyama, Yasuyuki; Hanaya, Hiroaki; Yamagata, Ryohei; Seito, Hajime; Nagao, Yuto; Kaneko, Hirohisa; Yamaguchi, Toshiyuki*; Yagi, Norihiko*; Takagi, Masahide*; et al.

JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 174, 2013/01

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2012-046.pdf

The electron accelerator and the -ray irradiation facility have been operated without serious trouble. The annual operation time in FY 2011 for the electron accelerator, the first, the second cobalt irradiation facility and food irradiation facility are 1,059 h, 18,722 h, 9,976 h and 7,427 h, respectively. Typically repairs were next ones. The beam control circuit trouble and the isolation trouble by mixing in of air into SF gas at electron accelerator were repaired. The maintenance check of the second irradiation facility was done. The Co sources were purchased and loaded to the second irradiation facility. Forty five pencil sources of Co with length of 30 cm each, eight coin sources of Co and the -ray radiographic apparatus with a Co source were disposed to Japan Radioisotope Association (JRIA).

Expert system of hydrochemical modeling methods for geological disposal of HLW; Know-how of hydrochemical investigation and modeling in literature survey stage to detail investigation stage

Iwatsuki, Teruki; Mizuno, Takashi; Kunimaru, Takanori; Amano, Yuki; Matsuzaki, Tatsuji; Semba, Takeshi

Genshiryoku Bakkuendo Kenkyu (CD-ROM), 19(2), p.51 - 63, 2012/12

https://doi.org/10.3327/jnuce.19.51

Various engineers from different generations concern with geological disposal project of high-level radioactive waste (HLW) over time. It requires to manage information to ensure the traceability of the decision making process and the inheritance of technique involved in project management. We developed Expert system available on the web to manage inheritable knowledge related to procedure, know-how and the notice of investigation techniques for deep geological environment. This report provides an overview of expert system and the one of contents regarding hydrochemical modeling and the updating method in literature survey stage detail investigation stage of geological disposal project.

Utilization of the -ray irradiation facilities and electron accelerator

Kaneko, Hirohisa; Haruyama, Yasuyuki; Hanaya, Hiroaki; Yamagata, Ryohei; Seito, Hajime; Nagao, Yuto; Yamaguchi, Toshiyuki*; Yagi, Norihiko*; Takagi, Masahide*; Kawashima, Ikuo*; et al.

JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 175, 2012/01

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2011-043.pdf

Irradiation facilities and an electron accelerator were operated for various research subjects according to the operation plan in FY 2010 without serious trouble. Utilization was stopped until the end of the fiscal year due to inspection etc., after the earthquake occurred on March 11. The number at -ray irradiation facilities increased in the field of environment and basic technology, and decreased in the field of material processing and resource & bio-technology. The number of research subjects at the electron accelerator increased in the research fields of material for space, and decreased in the field of material processing and joint use.

Utilization of electron accelerator and -ray irradiation facilities

Kaneko, Hirohisa; Haruyama, Yasuyuki; Hanaya, Hiroaki; Yamagata, Ryohei; Seito, Hajime; Yamaguchi, Toshiyuki*; Yagi, Norihiko*; Takagi, Masahide*; Kawashima, Ikuo*; Matsuzaki, Shinya*

JAEA-Review 2010-065, JAEA Takasaki Annual Report 2009, P. 183, 2011/01

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2010-065.pdf

An electron accelerator and three -ray irradiation facilities were operated for various research subjects according to the operation plan in FY 2009 without serious trouble. The number of experiment subjects at the electron accelerator increased in the research fields of materials for space and heat-resist material, and decreased in the field of basic technology and nuclear facilities. The number at -ray irradiation facilities increased in the field of nuclear facilities, and decreased in the field of materials processing and resource & bio-technology.