PSTEP: Project for solar-terrestrial environment prediction

Kusano, Kanya*; Ichimoto, Kiyoshi*; Ishii, Mamoru*; Miyoshi, Yoshizumi*; Yoden, Shigeo*; Akiyoshi, Hideharu*; Asai, Ayumi*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Goto, Tadanori*; et al.

Earth, Planets and Space (Internet), 73(1), p.159_1 - 159_29, 2021/12

https://doi.org/10.1186/s40623-021-01486-1

The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.

Application of capillary electrophoresis with laser-induced fluorescence detection for the determination of trace neodymium in spent nuclear fuel using complexation with an emissive macrocyclic polyaminocarboxylate probe

Haraga, Tomoko; Saito, Shingo*; Sato, Yoshiyuki; Asai, Shiho; Hanzawa, Yukiko; Hoshino, Hitoshi*; Shibukawa, Masami*; Ishimori, Kenichiro; Takahashi, Kuniaki

Analytical Sciences, 30(7), p.773 - 776, 2014/07

https://doi.org/10.2116/analsci.30.773

A simple and rapid method with low radiation exposure risk was developed for the determination of neodymium in spent nuclear fuel by CE with LIF detection using a fluorescent ligand having a macrocyclic hexadentate polyaminocarboxylate structure. The concentration of Nd(III) in a spent nuclear fuel sample was determined with no interference from various matrix elements, including lanthanides and uranium (at a 200-fold excess), with 92 3% recovery. This is due to method's high resolution based on establishing a ternary complex equilibrium during migration in which the hydroxyl ion plays an auxiliary role.

Temporal electric conductivity variations of hydrogenated amorphous silicon due to high energy protons

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

Journal of Non-Crystalline Solids, 358(17), p.2039 - 2043, 2012/09

https://doi.org/10.1016/j.jnoncrysol.2011.12.111

Electrical conductivity variations of undoped, n-type and p-type hydrogenated amorphous silicon (a-Si:H) thin films irradiated with various energy protons are systematically investigated in this study. Dark conductivity (DC) and photoconductivity (PC) of the undoped samples increased at first due to proton irradiation and then decrease dramatically with increasing proton fluence. However, increased PC was metastable and gradually decreased with time. Similar results were observed in the n-type a-Si:H, whereas the monotonic decrease was observed in the p-type one. The degrees of the DC and the PC decreases became lower as the irradiated proton energy was higher. The increases of both DC and PC are attributed to the temporal donor like center generation, although the additional proton irradiation decrease both the DC and PC by the accumulation of radiation-induced defects, which are act as deep traps and compensate carriers.

Electric properties of undoped hydrogenated amorphous silicon semiconductors irradiated with self-ions

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

Nuclear Instruments and Methods in Physics Research B, 285, p.107 - 111, 2012/08

https://doi.org/10.1016/j.nimb.2012.05.010

Electron and proton irradiation effects on substrate-type amorphous silicon solar cells

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

Proceedings of 37th IEEE Photovoltaic Specialists Conference (PVSC-37) (CD-ROM), p.001615 - 001619, 2011/06

https://doi.org/10.1109/PVSC.2011.6186265

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.

Mock-up test results of monoblock-type CFC divertor armor for JT-60SA

Higashijima, Satoru; Sakurai, Shinji; Suzuki, Satoshi; Yokoyama, Kenji; Kashiwa, Yoshitoshi; Masaki, Kei; Shibama, Yusuke; Takechi, Manabu; Shibanuma, Kiyoshi; Sakasai, Akira; et al.

Fusion Engineering and Design, 84(2-6), p.949 - 952, 2009/06

https://doi.org/10.1016/j.fusengdes.2009.02.021

An upgrading device of JT-60 tokamak with fully superconducting coils (JT-60SA) is constructed under both the Japanese domestic program and the international program "Broader Approach". The maximum heat flux to JT-60SA divertor is estimated to 15 MW/m for 100 s, and a monoblock-type CFC divertor armor is promising. The JT-60SA armor consists of CFC monoblocks, a cooling CuCrZr screw-tube, and a thin OFHC-Cu buffer layer, and the brazed joints are essential for the armor. Metalization inside CFC monoblock is applied for further improvement, and we confirmed again that the mock-up has heat removal capability in excess of ITER requirement. For optimization of the fabrication method and understanding of the production yield, the mock-ups corresponding to quantity produced in one furnace is also produced, and the half of the mock-ups could remove 15 MW/m as required. This summarizes the recent progress of design and mock-up test results for JT-60SA divertor armor.

CT injection experiment in JFT-2M

Ogawa, Hiroaki; Ogawa, Toshihide; Tsuzuki, Kazuhiro; Kawashima, Hisato; Kasai, Satoshi*; Kashiwa, Yoshitoshi; Hasegawa, Koichi; Suzuki, Sadaaki; Shibata, Takatoshi; Miura, Yukitoshi; et al.

Fusion Science and Technology, 49(2), p.209 - 224, 2006/02

https://doi.org/10.13182/FST06-A1096

no abstracts in English

Measurement of for the doublet in Cu

Hou, L.; Ishii, Tetsuro; Asai, Masato; Hori, Junichi; Ogawa, Kengo*; Nakada, Hitoshi*

Physical Review C, 68(5), p.054306_1 - 054306_6, 2003/11

https://doi.org/10.1103/PhysRevC.68.054306

Lifetimes of excited states in Cu were measured by the -- coincidence with two BaF detectors through the decay of Cu produced by the (,) reaction. The halflife of the 2 state at 84~keV was obtained as 7.84(8)~ns, corresponding to the value of 0.00777(8)~. A shell model calculation with a minimum model space of gives a good prediction of this value by using experimental g-factors of neighboring nuclei. This small value can be explained by a shell model calculation with the model space.

The Report of inspection and repair technology of sodium cooled reactors

Kisohara, Naoyuki; Uchita, Masato; Konomura, Mamoru; Kasai, Shigeo; Soman, Yoshindo; Shimakawa, Yoshio; Hori, Toru; Chikazawa, Yoshitaka; Miyahara, Shinya; Hamada, Hirotsugu; et al.

JNC TN9400 2003-002, 109 Pages, 2002/12

JNC-TN9400-2003-002.pdf:8.12MB

Sodium is the most promising candidate of an FBR coolant because of its excellent properties such as high thermal conductivity. Whereas, sodium reacts with water/air and its opaqueness makes it difficult to inspect sodium components. These weaknesses of sodium affect not only plant safety but also plant availability (economy). To overcome these sodium weak points, the appropriate countermeasure must be adopted to commercialized FBR plants. This report describes the working group activities for sodium/water reaction of steam generators (SG), in-service inspection for sodium components and sodium leak due to sodium components boundary failure. The prospect of each countermeasure is discussed in the viewpoint of the commercialized FBR plants. (1)Sodium/water reaction. The principle of the countermeasure for sodium/water reaction accidents was organized in the viewpoint of economy (the investment of SG and the plant availability). The countermeasures to restrain failure propagation were investigated for a large-sized SG. Preliminary analysis revealed the possibility of minimizing tubes failure propagation by improving the leak detection system and the blow down system. Detailed failure propagation analysis will be required and the early water leak detection system and rapid blow down system must be evaluated to realize its performance. (2)In-service inspection (ISI&R). The viewpoint of the commercialized plant's ISI&R was organized by comparing with the prototype reactor's ISI&R method. We also investigated short-term ISI&R methods without sodium draining to prevent the degrading of the plant availability, however, it is difficult to realize them with the present technology. Hereafter, the ISI&R of the commercialized plants must be defined by considering its characteristics. (3)Sodium leak from the components. This report organized the basic countermeasure policy for primary and secondary sodium leak accidents. Double-wall structure of sodium piping was ...