High statistics scattering experiment using high intensity pion beams at J-PARC

Miwa, Koji*; Hasegawa, Shoichi; Hayakawa, Shuhei; Hosomi, Kenji; Imai, Kenichi; Kondo, Yasuhiro; Naruki, Megumi; Sako, Hiroyuki; Sato, Susumu; Sugimura, Hitoshi; et al.

JPS Conference Proceedings (Internet), 17, p.041002_1 - 041002_6, 2017/07

https://doi.org/10.7566/JPSCP.17.041002

Bioaccessibility of radioactive cesium in soils

Takahara, Shogo; Ikegami, Maiko*; Yoneda, Minoru*; Kondo, Hitoshi*; Ishizaki, Azusa; Shimada, Yoko*

Dai-21-Kai Chikasui, Dojo Osen To Sono Boshi Taisaku Ni Kansuru Kenkyu Shukai Koenshu (CD-ROM), p.505 - 510, 2015/06

BB2014-3402.pdf:0.58MB

Doses received by the public are necessary information in management of radiation exposures in areas contaminated by the Fukushima Daiichi Nuclear Power Plant (1F) accident. Direct ingestion of contaminated soil is one of the exposure pathways which is a concern for the people living in the areas in terms of children's exposure. Therefore in order to manage efficiently the middle and the long term exposures with a sense of safety of the people, we have to clarify the contribution of this pathway to the doses received by those. However, a fractional absorption of radioactive cesium in gastrointestinal system has not been evaluated yet. We evaluated this factor based on the results of a physiologically based extraction test and an extraction test with hydrochloric acid, which is adopted in Japanese national law to evaluate a fractional absorption of heavy metals in gastrointestinal system. In addition, we assessed the doses to the public from this pathway after the 1F accident.

Structure of Pt(111)/ionomer membrane interface and its bias-induced change in membrane electrode assembly

Masuda, Takuya*; Fukumitsu, Hitoshi*; Kondo, Toshihiro*; Naohara, Hideo*; Tamura, Kazuhisa; Sakata, Osami*; Uosaki, Kohei*

Journal of Physical Chemistry C, 117(23), p.12168 - 12171, 2013/06

https://doi.org/10.1021/jp402251z

The structure of the perfluorosulfonated ionomer (PFSI)/Pt(111) interface in a membrane electrode assembly (MEA)-like configuration of a polymer electrolyte membrane (PEM) fuel cell, that is, a vacuum evaporated Pt layer/PEM(Nafion membrane)/PFSI(adhesion Nafion layer)/Pt(111) single crystal, and its bias-induced change were investigated by surface X-ray scattering measurement at an atomic level. Crystal truncation rod measurement shows that PFSI adsorbed on the Pt(111)-(11) surface without bias. When the Pt(111) electrode was positively biased to form Pt oxide, the PFSI layer was detached from the Pt surface and oxygen atoms penetrated into the Pt lattice.

Anomalous enhancement in radiation induced conductivity of hydrogenated amorphous silicon semiconductors

Sato, Shinichiro; Sai, Hitoshi*; Oshima, Takeshi; Imaizumi, Mitsuru*; Shimazaki, Kazunori*; Kondo, Michio*

Nuclear Instruments and Methods in Physics Research B, 286, p.29 - 34, 2012/09

https://doi.org/10.1016/j.nimb.2012.02.039

Electric conductivity variations of undoped hydrogenated amorphous silicon (a-Si:H) semiconductors induced by swift protons are investigated. The results show that the conductivity drastically increases at first and then decreases on further irradiation. The conductivity enhancement observed only in the low fluence regime lasts for a prolonged period of time when proton irradiation stops in this fluence regime. On the other hand, the photosensitivity has a minimum value around the conductivity peak. This fact indicates that non-equilibrium carriers do not play a dominant role in the electric conduction in this fluence regime. It is found that the anomalous conductivity enhancement is dominated by donor center generation in the low fluence regime. At higher fluences the variation in electric conductivity becomes dominated by non-equilibrium carriers as the generated donor centers disappear. This is a general interpretation of radiation induced conductivity in semiconductors.

Temporal donor generation in undoped hydrogenated amorphous silicon induced by swift proton bombardment

Sato, Shinichiro; Sai, Hitoshi*; Oshima, Takeshi; Imaizumi, Mitsuru*; Shimazaki, Kazunori*; Kondo, Michio*

Applied Physics Express, 4(6), p.061401_1 - 061401_3, 2011/06

https://doi.org/10.1143/APEX.4.061401

Seebeck coefficient variations of undoped hydrogenated amorphous silicon (a-Si:H) semiconductors due to swift proton irradiation were investigated using an in-situ thermoelectric power measurement system. Undoped a-Si:H irradiated with 3.0 MeV protons at a fluence regime of 3.110 - 5.010/cm showed a negative Seebeck coefficient although the Seebeck effect was not observed at fluences above 5.310 /cm. These results suggest that donor like centers are generated by low fluence proton irradiation, whereas the donor centers are compensated by radiation-induced defects or themselves disappear after high fluence proton irradiation. These effects decay with time, giving the donor centers a temporal nature.

A Study for the safety evaluation of geological disposal of TRU waste and influence on disposal site design by change of amount of TRU waste (Joint research)

Hasegawa, Makoto; Kondo, Hitoshi; Kamei, Gento; Hirano, Fumio; Mihara, Morihiro; Takahashi, Kuniaki; Funabashi, Hideyuki; Kawatsuma, Shinji; Ueda, Hiroyoshi*; Oi, Takao*; et al.

JAEA-Research 2011-003, 47 Pages, 2011/02

JAEA-Research-2011-003.pdf:3.99MB

In 2009, NUMO and JAEA set up a technical commission to investigate the reasonable TRU waste disposal following a cooperation agreement between these two organizations. In this report, the calculation result of radionuclide transport for a TRU waste geological disposal system was described, by using the TIGER code and the GoldSim code at identical terms. Comparing the calculation result, a big difference was not seen. Therefore, the reliability of both codes was able to be confirmed. Moreover, the influence on the disposal site design (Disposal capacity: 19,000 m) was examined when 10% of the amount of TRU waste increased. As a result, it was confirmed that the influence of the site design was very little based on the concept of the Second Progress Report on Research and Development for TRU Waste Disposal in Japan.

Proton-induced photoconductivity increment and the thermal stability of a-Si:H thin film

Sato, Shinichiro; Sai, Hitoshi*; Oshima, Takeshi; Imaizumi, Mitsuru*; Shimazaki, Kazunori*; Kondo, Michio*

Journal of Non-Crystalline Solids, 356(41-42), p.2114 - 2119, 2010/09

https://doi.org/10.1016/j.jnoncrysol.2010.07.018

Photoconductivity (PC) variations of device-grade a-Si:H thin films due to proton irradiation are investigated in this paper. We performed in-situ measurements of the PC variations induced by 0.10, 1.0 and 10 MeV proton irradiations. The irradiation initially caused an increase in PC in all sample. However, continued irradiation resulted in a dramatic decrease as the irradiation fluence increased. The results obtained in this study suggest that the PC increment is caused not by accumulation of displacement damage. The results of the temperature dependence of PC for a-Si:H before and after 10 MeV proton irradiation showed that such a proton-induced PC increment consisted of two components: one thermally stable and one metastable. The thermally metastable component disappeared in the temperature region of 300 to 340 K. On the contrary, radiation-induced defects were annealed above 340 K.

Anomalous photoconductivity variations of solar cell quality a-Si:H thin films induced by proton irradiation

Sato, Shinichiro; Sai, Hitoshi*; Imaizumi, Mitsuru*; Shimazaki, Kazunori*; Kondo, Michio*; Oshima, Takeshi

Proceedings of 34th IEEE Photovoltaic Specialists Conference (PVSC-34) (CD-ROM), p.002354 - 002358, 2009/06

Photoconductivity (PC) variations of a-Si:H thin films irradiated with 0.10, 1.0 or 10 MeV protons were investigated. According to the results, the PC values of all samples once increased and after that decreased dramatically. In order to obtain the knowledge about the anomalous PC increment, time dependence of the PC value increased by 10 MeV proton irradiation was also investigated. As a result, even the PC value after 270 hours was over twice higher than that before the irradiation, though the PC values decreased with time. However, the PC value became almost equivalent to the PC before the proton irradiation by applying light-soaking. These results mean that the anomalous PC increment is metastable.

Induction of mutations by the ion beam irradiation to the bulb-scales of cv. Acapulco.

Kondo, Masayoshi*; Koike, Yosuke*; Hase, Yoshihiro; Yokota, Yuichiro; Kobayashi, Hitoshi*

JAEA-Review 2007-060, JAEA Takasaki Annual Report 2006, P. 75, 2008/03

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2007-060.pdf

no abstracts in English

Numerical simulation system "three-dimensional virtual plant vibration simulator" for nuclear plants by using assembled structural analysis

Nishida, Akemi; Matsubara, Hitoshi; Tian, R.; Hazama, Osamu; Suzuki, Yoshio; Araya, Fumimasa; Nakajima, Norihiro; Tani, Masayuki; Kondo, Makoto

Nihon Genshiryoku Gakkai Wabun Rombunshi, 6(3), p.376 - 382, 2007/09

https://doi.org/10.3327/taesj.J06.021

Unexpected accidents such as oil-tank fires caused by the earthquake and breakage of pipes of nuclear plants have occurred over the past several years. Higher reliability is thus now increasingly expected to maintain the safety of infrastructures. We have been intensely focused on the construction of an analysis system called the "three-dimensional virtual vibration testbed," which is a numerical simulation system for a nuclear plant which considers the interconnection of machines, pipes, buildings, and their foundations under real operating conditions. In this paper, the "part-wise analysis method" is proposed in which each structural component is treated independently and analyzed as an assembly structure. Further, the system configurations in a parallel distribution environment are described. This study shows one of the successful examples of the application of this method to a nuclear-plant cooling system that has tens of millions of degrees of freedom.