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Journal Articles

Preliminary test of the EA-AGE3 system for $$^{14}$$C measurement of CaCO$$_{3}$$ samples and coral-based estimation of marine reservoir correction in the Ogasawara Islands, Northwestern Subtropical Pacific

Kokubu, Yoko; Mitsuguchi, Takehiro*; Watanabe, Takahiro; Yamada, Tsutomu*; Asami, Ryuji*; Iryu, Yasufumi*

Radiocarbon, 61(5), p.1593 - 1601, 2019/10

 Times Cited Count:0 Percentile:100(Geochemistry & Geophysics)

We performed $$^{14}$$C measurements of two fossil and one modern corals using a combined system of an elemental analyzer and an automated graphitization equipment AGE3 (EA-AGE3 system) and JAEA-AMS-TONO. The $$^{14}$$C concentrations (pMC values) of mid-Holocene Okinawa corals obtained by our EA-AGE3 system appear to be slightly higher than those obtained by the conventional graphitization method using phosphoric acid. The pMC increase in our EA-AGE3 system may result in significant underestimation of $$^{14}$$C age especially for older samples (e.g., 10,000 BP); however, the pMC increase is negligible in $$^{14}$$C measurements of modern or recent samples. We applied the EA-AGE3 method to the pre- and post-bomb annual-band samples from the modern Ogasawara coral for $$^{14}$$C measurements. On the basis of the pre-bomb coral $$^{14}$$C data, we estimated marine reservoir correction ($$Delta$$R) around Ogasawara Islands and its stability between $$sim$$1900 and 1950 AD.

Journal Articles

Development of an analytical method for estimating three-dimensional distribution of sediment-associated radiocesium at a reservoir bottom

Ochi, Kotaro; Urabe, Yoshimi*; Yamada, Tsutomu*; Sanada, Yukihisa

Analytical Chemistry, 90(18), p.10795 - 10802, 2018/09

 Times Cited Count:2 Percentile:78.24(Chemistry, Analytical)

After the Fukushima Daiichi Nuclear Power Station accident, the distributions of sediment-associated radiocesium have been investigated to evaluate the dispersion and accumulation of radiocesium in the reservoir field. To develop an analytical method for measuring the horizontal and vertical distributions of radiocesium on a wide scale, we obtained 253 $$gamma$$-ray spectra using a NaI(Tl) scintillation detector at the bottom of 64 ponds in Fukushima during 2014-2016. The depth profile of sediment-associated radiocesium was found to be correlated with intensities of scattered and photo peaks. In parallel, core sediments were collected in same ponds to validate the estimates. Good agreement was observed between the results of in situ spectrometry and core sampling. These results indicated that our developed method would be a good approach for understanding the behavior of radiocesium and determining whether decontamination of reservoirs is required.

Journal Articles

Outline and implementation status of decommissioning plan of JRR-4

Ishikuro, Yasuhiro; Nemoto, Tsutomu; Yamada, Yusuke; Oyama, Koji

Nippon Hozen Gakkai Dai-15-Kai Gakujutsu Koenkai Yoshishu, p.501 - 505, 2018/07

After operating until December 2010, JRR-4 was under periodical self-inspection for the next operation. After that, it suffered from the Great East Japan Earthquake on March 11, 2011. But it recovered almost a year later. However, we determined to decommission JRR-4 in September 2013. After that, we received the approval of the decommissioning plan of JRR-4 on June 7, 2017. And we received the approval of the change of the safety regulations related to it. Subsequently JRR-4 was shifted to decommission phase in December 2017. This report describes the outline of the decommissioning plan of JRR-4 and the implementation status.

Journal Articles

Altitude control performance improvement via preview controller for unmanned airplane for radiation monitoring system

Sato, Masayuki*; Muraoka, Koji*; Hozumi, Koki*; Sanada, Yukihisa; Yamada, Tsutomu*; Torii, Tatsuo

Nippon Koku Uchu Gakkai Rombunshu (Internet), 65(2), p.54 - 63, 2017/02

This paper is concerned with the design problem of preview altitude controller for Unmanned Airplane for Radiation Monitoring System (UARMS) to improve its control performance. UARMS has been developed for radiation monitoring around Fukushima Daiichi Nuclear Power Plant which spread radiation contaminant due to the huge tsunamis caused by the Great East Japan Earthquake. The monitoring area contains flat as well as mountain areas. The basic flight controller has been confirmed to have satisfactory performance with respect to altitude holding; however, the control performance for variable altitude commands is not sufficient for practical use in mountain areas. We therefore design preview altitude controller with only proportional gains by considering the practicality and the strong requirement of safety for UARMS. Control performance of the designed preview controller was evaluated by flight tests conducted around Fukushima Sky Park.

JAEA Reports

Radiation monitoring using manned helicopter around the nuclear power station in the fiscal year 2015 (Contract research)

Sanada, Yukihisa; Munakata, Masahiro; Mori, Airi; Ishizaki, Azusa; Shimada, Kazumasa; Hirouchi, Jun; Nishizawa, Yukiyasu; Urabe, Yoshimi; Nakanishi, Chika*; Yamada, Tsutomu*; et al.

JAEA-Research 2016-016, 131 Pages, 2016/10

JAEA-Research-2016-016.pdf:20.59MB

By the nuclear disaster of Fukushima Daiichi Nuclear Power Station (FDNPS), Tokyo Electric Power Company (TEPCO), caused by the East Japan earthquake and the following tsunami occurred on March 11, 2011, a large amount of radioactive materials was released from the NPS. After the nuclear disaster, airborne radiation monitoring using manned helicopter was conducted around FDNPS. In addition, background dose rate monitoring was conducted around Sendai Nuclear Power Station. These results of the aerial radiation monitoring using the manned helicopter in the fiscal 2015 were summarized in the report.

JAEA Reports

Application to contaminated water management in the Fukushima Daiichi Nuclear Power Station using the plastic scintillation fiber

Sanada, Yukihisa; Yamada, Tsutomu*; Sato, Yoshiharu; Nishizawa, Yukiyasu; Ishibashi, Satoshi*; Watanabe, Masahisa; Torii, Tatsuo

JAEA-Research 2016-011, 52 Pages, 2016/09

JAEA-Research-2016-011.pdf:10.54MB

In the Tokyo Electric Power Co.,Inc. the Fukushima Dai-ichi Nuclear Power Station, management of the contaminated water becomes the social problem, and the situation that severe correspondence is necessary continues to prevent an outflow to the ocean. Plastic scintillation fiber (PSF) can apply as technique to direct measure the concentration of radioactive material in the water at a tank and drainage. In this paper, the results of fundamental test was summarized to apply for monitoring of leakage to the tank and monitoring of drainage in the Fukushima Dai-ichi Nuclear Power Station.

JAEA Reports

Radiation monitoring using manned helicopter around the Fukushima Daiichi Nuclear Power Station in the fiscal year 2014 (Contract research)

Sanada, Yukihisa; Mori, Airi; Ishizaki, Azusa; Munakata, Masahiro; Nakayama, Shinichi; Nishizawa, Yukiyasu; Urabe, Yoshimi; Nakanishi, Chika; Yamada, Tsutomu; Ishida, Mutsushi; et al.

JAEA-Research 2015-006, 81 Pages, 2015/07

JAEA-Research-2015-006.pdf:22.96MB

By the nuclear disaster of Fukushima Daiichi Nuclear Power Station (NPS), Tokyo Electric Power Company (TEPCO), caused by the East Japan earthquake and the following tsunami occurred on March 11, 2011, a large amount of radioactive materials was released from the NPP. These results of the aerial radiation monitoring using the manned helicopter in the fiscal 2014 were summarized in the report.

Journal Articles

Development and application test of radiation detector for the UARMS

Sanada, Yukihisa; Yamada, Tsutomu; Ishibashi, Satoshi; Torii, Tatsuo

Dai-57-Kai Jido Seigyo Rengo Koenkai Koen Rombunshu (USB Flash Drive), p.695 - 698, 2014/11

The Great East Japan Earthquake that occurred on March 11, 2011, generated a series of large tsunami waves that caused serious damage to the Fukushima Daiichi Nuclear Power Plant, following which a large amount of radioactive material was discharged from the nuclear power plant into the environment. In JAEA and JAXA, UARMS (Unmanned Airplane Radiation Monitoring System) was developing as collaborative research. Here, we report about an aerial radiation monitoring technology for UARMS.

JAEA Reports

Study on engineering technologies in the Mizunami Underground Research Laboratory; FY2012 (Contract research)

Fukaya, Masaaki*; Noda, Masaru*; Hata, Koji*; Takeda, Yoshinori*; Akiyoshi, Kenji*; Ishizeki, Yoshikazu*; Kaneda, Tsutomu*; Sato, Shin*; Shibata, Chihoko*; Ueda, Tadashi*; et al.

JAEA-Technology 2014-019, 495 Pages, 2014/08

JAEA-Technology-2014-019.pdf:82.23MB

The researches on engineering technology in the Mizunami Underground Research Laboratory (MIU) plan consists of (1) research on engineering technology deep underground, and (2) research on engineering technology as a basis of geological disposal. The former research is mainly aimed in this study, which is categorized in (a) development of design and construction planning technologies, (b) development of construction technologies, (c) development of countermeasure technologies, and (d) development of technologies for security. In this study, the researches on engineering technology are being conducted in these four categories by using data measured during construction as a part of the second phase of the MIU plan.

JAEA Reports

Radiation monitoring using manned helicopter around the Fukushima Daiichi Nuclear Power Station in the fiscal year 2013 (Contract research)

Sanada, Yukihisa; Nishizawa, Yukiyasu; Urabe, Yoshimi; Yamada, Tsutomu; Ishida, Mutsushi; Sato, Yoshiharu; Hirayama, Hirokatsu; Takamura, Yoshihide; Nishihara, Katsuya; Imura, Mitsuo; et al.

JAEA-Research 2014-012, 110 Pages, 2014/08

JAEA-Research-2014-012.pdf:169.17MB
JAEA-Research-2014-012(errata).pdf:0.27MB

By the nuclear disaster of Fukushima Daiichi Nuclear Power Station (NPS), Tokyo Electric Power Company (TEPCO), caused by the East Japan earthquake and the following tsunami occurred on March 11, 2011, a large amount of radioactive materials was released from the NPP. This document was summarized in the results of the aerial radiation monitoring using the manned helicopter in the fiscal 2013.

JAEA Reports

Research and development of in-situ measurement for radiation distribution of waterbed

Sanada, Yukihisa; Takamura, Yoshihide; Urabe, Yoshimi; Tsuchida, Kiyofumi; Nishizawa, Yukiyasu; Yamada, Tsutomu; Sato, Yoshiharu; Hirayama, Hirokatsu; Nishihara, Katsuya; Imura, Mitsuo; et al.

JAEA-Research 2014-005, 67 Pages, 2014/05

JAEA-Research-2014-005.pdf:52.68MB

Distribution of radiocesium existing on the waterbed such as lake or pond was concerned about at the present that passed for two years by an accident. Here, the direct measurement technique of the radiocesium concentration (in-situ measurement technique) was developed. This method was used an plastic scintillation detector (p-Scanner). This detector carried out quick measurement of a large area. In addition, the count-rate of p-Scanner was converted to the radiocesium concentration (Ba/kg-wet) by comparative measurement of $$gamma$$-ray spectrometer. We applied the technique to the agricultural pond in Fukushima and made a map of distribution of radiocesium concentration.

JAEA Reports

Radiation monitoring using the unmanned helicopter after the accident of the nuclear power plant

Sanada, Yukihisa; Nishizawa, Yukiyasu; Yamada, Tsutomu; Ikeda, Kazutaka*; Matsui, Masashi*; Tsuchida, Kiyofumi; Sato, Yoshiharu; Hirayama, Hirokatsu; Takamura, Yoshihide; Nishihara, Katsuya; et al.

JAEA-Research 2013-049, 129 Pages, 2014/03

JAEA-Research-2013-049.pdf:15.5MB

By the nuclear disaster of Fukushima Daiichi Nuclear Power Plant (NPP), Tokyo Electric Power Company (TEPCO), caused by the East Japan earthquake and the following tsunami occurred on March 11, 2011, a large amount of radioactive materials was released from the NPP. In recent years, technologies for autonomous unmanned helicopters (AUHs) have been developed and applied to natural disasters. In expectation of the application of the AUHs to aerial radiation monitoring, we had developed a remote radiation monitoring system. Then, we measured the radiation level by using unmanned helicopter in soil contaminated areas by radioactive cesium emitted from the NPP to evaluate ambient dose-rate distribution around the areas and to investigate the decontamination effect by the measurements before and after decontamination treatment. Here, we reports on the measurement technique and the result.

Journal Articles

Development and future plan of radiation measurement system using unmanned airclaft

Sanada, Yukihisa; Yamada, Tsutomu; Hirayama, Hirokatsu; Imura, Mitsuo; Nishizawa, Yukiyasu; Torii, Tatsuo

Dai-1-Kai Keisoku Jido Seigyo Gakkai Seigyo Bumon Maruchi Shimpojiumu Hobunshu (USB Flash Drive), 5 Pages, 2014/03

no abstracts in English

JAEA Reports

Development of grout materials for a geological disposal system for high-level radioactive waste, 2

Kawaguchi, Masanao; Nakanishi, Tatsuro; Kishi, Hirokazu; Nobuto, Jun*; Yamada, Tsutomu*; Fujita, Tomoo; Hatanaka, Koichiro

JAEA-Data/Code 2012-007, 250 Pages, 2012/11

JAEA-Data-Code-2012-007.pdf:20.55MB

Cementitious materials are commonly used for rock support, lining, and grouting, their pH plume are considered to have an adverse effect on long-term safety of a geological disposal system. In addition, during the emplacement of waste package with buffer material, it is required to limit amount of groundwater inflow to a certain level by grouting. Therefore, it is necessary to develop new grout materials with penetrability for smaller fractures. We have developed new grout materials, which have better penetrability and are environmentally more friendly than exinting cementitious grout materials since FY 2007. This sequel report shows the most appropriate composition and the penetration characteristic of new grout materials to be suitable for the ${it in-situ}$ experiment based on the result of indoor test carried out after FY 2008.

Journal Articles

Practical approach to decontamination of radioactive cesium-contaminated matter in agricultural region by improved wet classification and use of geomaterials

Ito, Kenichi*; Miyahara, Hidetaka*; Ujiie, Toru*; Takeshima, Toshikatsu*; Yokoyama, Shingo*; Nakata, Kotaro*; Nagano, Tetsushi; Sato, Tsutomu*; Hatta, Tamao*; Yamada, Hirohisa*

Nippon Genshiryoku Gakkai Wabun Rombunshi, 11(4), p.255 - 271, 2012/04

no abstracts in English

Journal Articles

The Project for grouting development for high level radioactive waste repository, 3; Study of allowable seepage water quantity by permiability test though contact face of buffer material blocks

Sekine, Ichiro*; Yamada, Tsutomu*; Sekiguchi, Takashi*; Fujita, Tomoo; Nakanishi, Tatsuro

Doboku Gakkai Heisei-23-Nendo Zenkoku Taikai Dai-66-Kai Nenji Gakujutsu Koenkai Koen Gaiyoshu (DVD-ROM), p.69 - 70, 2011/09

no abstracts in English

Journal Articles

The "Study on nuclear data by using a high intensity pulsed neutron source for advanced nuclear system" nuclear data project and the characteristics of the neutron beam line for the capture cross section experiments at J-PARC

Kiyanagi, Yoshiaki*; Kino, Koichi*; Furusaka, Michihiro*; Hiraga, Fujio*; Kamiyama, Takashi*; Kato, Kiyoshi*; Igashira, Masayuki*; Katabuchi, Tatsuya*; Mizumoto, Motoharu*; Oshima, Masumi; et al.

Journal of the Korean Physical Society, 59(2), p.1781 - 1784, 2011/08

 Times Cited Count:12 Percentile:35.25(Physics, Multidisciplinary)

The project of the comprehensive nuclear data research for the development of the advanced reactor systems had been executed successfully by eight organizations from 2005 to 2009. In this project, we constructed the pulsed neutron beamline that was aimed to obtain neutron capture cross-sections of long-lived fission products and minor actinides accurately. The energy spectra, spatial distributions, and pulses of the beam were studied by measurements and simulation calculations, and they were found to be consistent with those of the beamline design. In this paper, we present the overview of the project and the properties of the neutron beam provided by this beam line.

Journal Articles

The Project for grouting development for high level radioactive waste repository, 4; Development of superfine spherical silica grout

Yamada, Tsutomu*; Sekine, Ichiro*; Sekiguchi, Takashi*; Ishida, Hideaki*; Kishi, Hirokazu; Fukuoka, Naomi

Doboku Gakkai Heisei-22-Nendo Zenkoku Taikai Dai-65-Kai Nenji Gakujutsu Koenkai Koen Gaiyoshu (DVD-ROM), p.89 - 90, 2010/09

no abstracts in English

JAEA Reports

Development of grout materials for a geological disposal system for high-level radioactive waste

Fukuoka, Naomi; Shinkai, Fumiaki; Miura, Norihiko*; Nobuto, Jun*; Yamada, Tsutomu*; Naito, Morimasa

JAEA-Data/Code 2010-005, 353 Pages, 2010/07

JAEA-Data-Code-2010-005-01.pdf:8.91MB
JAEA-Data-Code-2010-005-02.pdf:46.47MB

High-level radioactive waste management in Japan is based on the multi-barrier concept, composed of the engineered barrier system and the surrounding geological formations. Although cementitious materials are commonly used for rock support, lining, and grouting, their pH plume are considered to have an adverse effect on long-term safety of a geological disposal system. In addition, during the emplacement of waste package with buffer material, it is required to limit amount of groundwater inflow into a disposal pit or tunnel to a certain level by grouting because the bentonite clay buffer is easy to swell in time by contact with the groundwater. Therefore, it is necessary to develop new grout materials with penetrability for smaller fractures. This report shows the most appropriate composition of new grout materials to be suitable for the in-situ experiment based on the result of indoor test.

Journal Articles

Development of superfine spherical silica grout as an alternative grouting material for the geological disposal of long-lived radioactive waste

Naito, Morimasa; Kishi, Hirokazu; Fukuoka, Naomi; Yamada, Tsutomu*; Ishida, Hideaki*

Proceedings of 18th International Conference on Nuclear Engineering (ICONE-18) (CD-ROM), 7 Pages, 2010/05

As an alternative grouting material for the geological repository of long-lived radioactive waste, the "Superfine Spherical silica Grout" (SFSG) material is developed using a fine spherical silica and a fine calcium hydroxide. The developed SFSG material takes an advantage of its smaller particle size distribution (max. $$sim$$1 micron or less) than those of the cementitious materials, and also provides a low alkaline environment so as to reduce unfavorable effects on the long-term performance of geological disposal system. The SFSG is a mixture of the super fine silica powder, the superfine calcium hydroxide and additives such as superplasticizer. Some preliminary laboratory experiments were carried out to characterize its fundamental properties from the viewpoint of practical use for geological disposal, which is required to be equivalent with the conventional cementitious materials in terms of penetrability, strength, pH performance and workability.

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