Study of charged particle activation analysis, 2; Determination of boron concentration in human blood samples

Ikebe, Yurie*; Oshima, Masumi*; Bamba, Shigeru*; Asai, Masato; Tsukada, Kazuaki; Sato, Tetsuya; Toyoshima, Atsushi*; Bi, C.*; Seto, Hirofumi*; Amano, Hikaru*; et al.

Applied Radiation and Isotopes, 164, p.109106_1 - 109106_7, 2020/10

https://doi.org/10.1016/j.apradiso.2020.109106

Boron Neutron Capture Therapy (BNCT) is a radiotherapy for the treatment of intractable cancer. In BNCT precise determination of B concentration in whole blood sample before neutron irradiation is crucial for control of the neutron irradiation time and the neutron dosimetry. We have applied the Charged Particle Activation Analysis (CPAA) to non-destructive and accurate determination of B concentration in whole blood sample. The experiment was performed at JAEA Tandem Accelerator using an 8 MeV proton beam. The 478 keV ray of Be produced in the B(p,)Be reaction was used to quantify the B, and rays of Co originating from the reaction with Fe in blood was used to normalize the -ray intensity. The results demonstrated that the present CPAA method can be applied to the determination of the B concentration in the blood sample.

observation of dislocation evolution in ferritic and austenitic stainless steels under tensile deformation by using neutron diffraction

Sato, Shigeo*; Kuroda, Asumi*; Sato, Kozue*; Kumagai, Masayoshi*; Harjo, S.; Tomota, Yo*; Saito, Yoichi*; Todoroki, Hidekazu*; Onuki, Yusuke*; Suzuki, Shigeru*

Tetsu To Hagane, 104(4), p.201 - 207, 2018/00

https://doi.org/10.2355/tetsutohagane.TETSU-2017-082

Microstructure analysis in steel using quantum beam diffraction method

Sato, Shigeo*; Onuki, Yusuke*; Shobu, Takahisa; Shiro, Ayumi*; Tashiro, Hitoshi*; Todoroki, Hidekazu*; Suzuki, Shigeru*

Kinzoku, 86(8), p.654 - 660, 2016/08

http://ci.nii.ac.jp/naid/40020920777

no abstracts in English

Environmental remediation for the upstream of Yotsugi Mill Tailings Pond, Ningyo-toge Uranium Mine

Saito, Hiroshi; Sato, Yasushi*; Sakamoto, Atsushi*; Torikai, Kazuyoshi; Fukushima, Shigeru; Sakao, Ryota; Taki, Tomihiro

JAEA-Technology 2015-063, 119 Pages, 2016/03

JAEA-Technology-2015-063.pdf:86.2MB

Ningyo-toge Environmental Engineering Center has been conducting environmental remediation of the Ningyo-toge Uranium Mine, after decades of mine-related activities were terminated. Its purposes are to take measures to ensure safety and radiation protection from the exposure pathways to humans in future, and to prevent the occurrence of mining pollution. As part of the remediation, upstream part of the Yotsugi Mill Tailings Pond, the highest prioritized facility, has been remediated to fiscal year 2012. Multi-layered capping has been constructed using natural material, after specifications and whole procedure being examined in terms of long-term stability, radiation protection, economics, etc. Monitoring has been carried out to confirm the effectiveness of the capping, in terms of settlement, dose and radon exhalation rates, etc. Monitoring of drainage volume of penetrated rainwater is planned. Accumulated data will be examined and used for remediation of downstream part of the Pond.

Distribution and anisotropy of dislocations in cold-drawn pearlitic steel wires analyzed using micro-beam X-ray diffraction

Sato, Shigeo*; Shobu, Takahisa; Sato, Kozue*; Ogawa, Hiromi*; Wagatsuma, Kazuaki*; Kumagai, Masayoshi*; Imafuku, Muneyuki*; Tashiro, Hitoshi*; Suzuki, Shigeru*

ISIJ International, 55(7), p.1432 - 1438, 2015/07

https://doi.org/10.2355/isijinternational.55.1432

To characterize the distribution and anisotropy of dislocations in cold-drawn pearlitic steel wires, X-ray diffraction line-profile analysis was performed using synchrotron radiation micro-beams. The plastic shear strain was generally more severe near the surface than the center of the wire, whereas the dislocation density distribution was almost constant from the center to the surface. On the other hand, the dislocation rearrangement, which evolves the dislocation cell structure, progressed closer to the surface. It was also revealed that a difference between the hardness in axial and transverse wire directions could be explained by anisotropic dislocation density. Line-profile analysis based on diffraction data at elevated temperatures was performed. Whereas the cementite recovery progressed at a constant rate, the ferrite phase recovery rate was temperature-dependent, suggesting that the ferrite phase recovery was less related to that of the cementite phase.

Evaluation of the applicability of a new quantitative rock mass classification method at the Mizunami Underground Research Laboratory

Kuji, Masayoshi*; Asai, Hideaki*; Hashizume, Shigeru; Horiuchi, Yasuharu; Sato, Toshinori; Matsui, Hiroya

JAEA-Technology 2013-022, 72 Pages, 2013/10

JAEA-Technology-2013-022.pdf:5.3MB

Rock mass classifications are used for design and construction of underground structures. However, the classification methods commonly used in Japan are qualitative and inadequate for estimating the actual mechanical properties of a rock mass based on site specific geological features. Considering the design, construction and safe operation of large underground facilities, an important requirement is to utilize a rock mass classification method that can estimate site specific rock mechanical properties based on surface-based investigations and geological observations during excavation. For this study, a new quantitative rock mass classification method based on JGS standard was proposed and applied to the sedimentary formations and the granite at MIU. The results were compared with the rock mass classification system developed by CRIEPI and commonly used in JAPAN. Then the applicability of the new rock mass classification could be evaluated.

Mizunami Underground Research Laboratory Project, Annual report for fiscal year 2011

Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Ishibashi, Masayuki; Sasao, Eiji; Hikima, Ryoichi; Tanno, Takeo; Sanada, Hiroyuki; et al.

JAEA-Review 2013-018, 169 Pages, 2013/09

JAEA-Review-2013-018.pdf:15.71MB

Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) Project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). The MIU Project has three overlapping phases: Surface-based Investigation phase (Phase I), Construction phase (Phase II), and Operation phase (Phase III). The MIU Project has been ongoing the Phase II and the Phase III in 2011 fiscal year. This report shows the results of the investigation, construction and collaboration studies in fiscal year 2011, as a part of the Phase II and Phase III based on the MIU Master Plan updated in 2010.

Change in the electrical performance of GaAs solar cells with InGaAs quantum dot layers by electron irradiation

Oshima, Takeshi; Sato, Shinichiro; Imaizumi, Mitsuru*; Nakamura, Tetsuya*; Sugaya, Takeyoshi*; Matsubara, Koji*; Niki, Shigeru*

Solar Energy Materials and Solar Cells, 108, p.263 - 268, 2013/01

https://doi.org/10.1016/j.solmat.2012.09.027

GaAs solar cells which have a PiN structure with 50 self-organized InGaAs Quantum Dot (QD) layers were irradiated with 1 MeV electrons up to 110 /cm. After irradiation at 110/cm, the remaining factor of I, V and P for the InGaAs 50 QD solar cell becomes 80, 90 and 55% of the initial values, respectively. On the other hand, those values for non QD GaAs solar cells decrease to 95, 80 and 63% of the initial values, respectively. Since the i-layer for the 50 QD solar cells (1.1 m) is thicker than the non QD solar cells (660 nm), the larger degradation of I for the 50 QD solar cells than the non QD ones can be interpreted in terms that the carrier recombination in the i-layer for the 50 QD solar cells is larger than that for the non QD solar cells. For V, the 50 QD solar cells showes better radiation resistance than the non QD solar cells. Furthermore, the annealing behavior of the electrical characteristics for the 50 QD and the non QD solar cells was investigated at RT under AM 0 immediately after the irradiation. As a result, the recovery of the electrical characteristics for both solar cells was observed, and the GaAs solar cells shows relatively larger recovery compared to the 50 QD solar cells. Although the mechanism of this recovery has not yet been clarified, the origin of this recovery is thought not to come from the existence of QDs because the GaAs solar cell without QD layers also shows the recovery.

The Creep rupture strength evaluation in welded joint of Mod.9Cr-1Mo steel

Wakai, Takashi; Nagae, Yuji; Takaya, Shigeru; Obara, Satoshi; Date, Shingo*; Yamamoto, Kenji*; Kikuchi, Koichi*; Sato, Kenichiro*

Tainetsu Kinzoku Zairyo Dai-123-Iinkai Kenkyu Hokoku, 52(2), p.147 - 159, 2011/07

By employing high-Cr ferritic steels to the structural materials for JSFR, a compact plant designing can be achieved. It contributes to reduce the construction cost and to enhance the freedom of designing. Among the high-Cr ferritic steels, modified 9Cr-1Mo steel (compatible to ASTM A335 P91) is a candidate of the structural material for the demonstration facility of JSFR, because the steel has superior microstructure stability at elevated temperature for long time. However, remarkable creep strength degradation has been observed in the welded joint of high-Cr ferritic steels, especially in long-term region. It is known as "Type-IV damage". In the elevated temperature designing for the fast reactors, such creep strength degradation must be taken into account properly. Therefore, the creep strength assessment procedure and the allowable stress for the welded joints made of modified 9Cr-1Mo steel have been proposed. In this study, (1) a series of creep rupture tests to verify the validity of the creep strength assessment procedure was performed. (2) Applicability of the creep strength assessment procedure to the creep fatigue strength assessment of the welded joints made of modified 9Cr-1Mo steel was investigated. (3) Metallurgical examinations of creep ruptured specimens were carried out to confirm the contribution of "Type-IV damage". As a result, it was demonstrated that the creep strength assessment procedure was validated using the long-term creep rupture test results less than 30,000h and that the creep strength assessment procedure was applicable to the creep-fatigue strength assessment based on some uniaxial creep-fatigue test results.

Change in the electrical performance of InGaAs quantum dot solar cells due to irradiation

Oshima, Takeshi; Sato, Shinichiro; Morioka, Chiharu*; Imaizumi, Mitsuru*; Sugaya, Takeyoshi*; Niki, Shigeru*

Proceedings of 35th IEEE Photovoltaic Specialists Conference (PVSC-35) (CD-ROM), p.002594 - 002598, 2010/06

https://doi.org/10.1109/PVSC.2010.5614152

Quantum Dot (QD) solar cells are regarded as promising candidate for solar cells with superior high efficiency. For space application, it is important to understand radiation effects in such QD solar cells. However, radiation response of QD solar cells has not yet been clarified. In this study, we irradiate QD solar cells with electrons, and investigate change in the electrical performance of the QD solar cells. PiN structure solar cells with self-organized InGaAs QD layers grown on GaAs (001) substrates by MBE were used in this study. The efficiency for the 30 QD layer solar cells without anti-reflector coating is 7.0% under AM 1.5 at 25 C. The samples were irradiated with electrons at 1 MeV at room temperature. The current-voltage characteristics under AM0 and the quantum efficiency (QE) were measured before and after irradiations. Electron irradiation effects on single junction GaAs solar cells fabricated under the same process were also studied for comparison. The value of QE for both the GaAs solar cells with and without QD layers slightly decreases due to the irradiation at 110/cm, and no remarkable decrease in the increment of the QE in a long wavelength region due to the existence of QDs is observed.