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JAEA Reports

Analysis of the radioactivity concentrations in low-level radioactive waste generated from JRR-2, JRR-3 and hot laboratory facilities

Tobita, Minoru*; Haraga, Tomoko; Sasaki, Takayuki*; Seki, Kotaro*; Omori, Hiroyuki*; Kochiyama, Mami; Shimomura, Yusuke; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Data/Code 2019-016, 72 Pages, 2020/02

JAEA-Data-Code-2019-016.pdf:2.67MB

In the future, radioactive wastes which generated from research and testing reactors in Japan Atomic Energy Agency are planning to be buried for the near surface disposal. Therefore, it is required to establish the method to evaluate the radioactivity concentrations of radioactive wastes by the time it starts disposal. In order to contribute to this work, we collected and analyzed the samples generated from JRR-2, JRR-3 and Hot laboratory facilities. In this report, we summarized the radioactivity concentrations of 25 radionuclides ($$^{3}$$H, $$^{14}$$C, $$^{36}$$Cl, $$^{60}$$Co, $$^{63}$$Ni, $$^{90}$$Sr, $$^{94}$$Nb, $$^{93}$$Mo, $$^{99}$$Tc, $$^{108m}$$Ag, $$^{126}$$Sn, $$^{129}$$I, $$^{137}$$Cs, $$^{152}$$Eu, $$^{154}$$Eu, $$^{233}$$U, $$^{234}$$U, $$^{238}$$U, $$^{238}$$Pu, $$^{239}$$Pu, $$^{240}$$Pu, $$^{241}$$Pu, $$^{241}$$Am, $$^{243}$$Am, $$^{244}$$Cm) which were obtained from radiochemical analysis of those samples.

Journal Articles

Fabrication and short-term irradiation behaviour of Am-bearing MOX fuels

Kihara, Yoshiyuki; Tanaka, Kosuke; Koyama, Shinichi; Yoshimochi, Hiroshi; Seki, Takayuki; Katsuyama, Kozo

NEA/NSC/R(2017)3, p.341 - 350, 2017/11

In order to investigate the effect of the addition of americium to MOX fuels on the irradiation behaviour, the "Am-1" program is being conducted at the JAEA. The Am-1 program consists of two short-term irradiation tests of 10-min and 24-h irradiation periods, and a steady-state irradiation test. The short-term irradiation tests and their post irradiation examinations (PIEs) have been successfully completed. To date, the data for PIE of the Am-MOX fuels focused on the microstructural evolution and redistribution behaviour of Am at the initial stage of irradiation have been obtained and reported. In this paper, the results obtained from the Am-1 program are reviewed and detailed descriptions of the fabrication and inspection techniques for the Am-MOX fuels prepared for the program are provided. PIE data for the Am-MOX fuels at the initial stage of irradiation have been accumulated. In this paper, unpublished PIE data for the Am-MOX fuels are also presented.

JAEA Reports

Study on radionuclide analysis of rubble and plants for decommissioning of Fukushima Daiichi Nuclear Power Station

Seki, Kotaro; Sasaki, Takayuki*; Akimoto, Yuji*; Tokunaga, Takahito; Tanaka, Kiwamu; Haraga, Tomoko; Ueno, Takashi; Ishimori, Kenichiro; Hoshi, Akiko; Kameo, Yutaka

JAEA-Technology 2016-013, 37 Pages, 2016/07

JAEA-Technology-2016-013.pdf:2.09MB

In this study, based on the simple and rapid analytical method established from the wastes from research facilities, we created analytical schemes which is applicable to rubble and plants collected at Fukushima Daiichi, then transported to Nuclear Science Research Institute of JAEA. We examined the applicability, and confirmed quantifiability of radioactivity concentration with high recovery rate without being affected by fission products such as $$^{90}$$Sr and $$^{137}$$Cs.

JAEA Reports

Evaluation of fission product and actinide release behaviors focusing on their chemical forms; Phase relation and fission product release behavior resulting from interaction between molten zircaloy and irradiated MOX fuel

Tanaka, Kosuke; Miwa, Shuhei; Sato, Isamu; Hirosawa, Takashi; Sekine, Shinichi; Seki, Takayuki*; Tokoro, Daishiro*; Obayashi, Hiroshi; Koyama, Shinichi

JAEA-Research 2013-022, 62 Pages, 2014/01

JAEA-Research-2013-022.pdf:33.64MB

In order to establish the method for heating tests focused on the fission product release resulting from the high temperature chemical interaction between fuel and cladding material and to obtain the novel data on fission product release behaviors, the heating test was carried out with irradiate MOX fuel pellet and cladding.

Journal Articles

Generation of radioisotopes with accelerator neutrons by deuterons

Nagai, Yasuki; Hashimoto, Kazuyuki; Hatsukawa, Yuichi; Saeki, Hideya; Motoishi, Shoji; Sonoda, Nozomi; Kawabata, Masako; Harada, Hideo; Kin, Tadahiro*; Tsukada, Kazuaki; et al.

Journal of the Physical Society of Japan, 82(6), p.064201_1 - 064201_7, 2013/06

 Times Cited Count:30 Percentile:15.27(Physics, Multidisciplinary)

Journal Articles

Status of JAEA-AMS-MUTSU at 2010-2011

Kabuto, Shoji; Kinoshita, Naoki; Tanaka, Takayuki; Kuwabara, Jun; Seki, Takeo

Dai-24-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.9 - 12, 2011/07

A Tandetron Accelerator Mass Spectrometer (AMS) manufactured by High Voltage Engineering Europa in Netherlands had been set up at the Mutsu office of Aomori Research and Development Center, Japan Atomic Energy Agency (JAEA) in 1997. This AMS features 3 MV Tandetron accelerator and two independence beamlines for $$^{14}$$C and $$^{129}$$I measurement. In this report, we describe the summary of the current status at 2010-2011.

Journal Articles

Current status of $$^{14}$$C measurement at JAEA-AMS-MUTSU

Tanaka, Takayuki; Kabuto, Shoji; Kinoshita, Naoki; Seki, Takeo

Nagoya Daigaku Kasokuki Shitsuryo Bunsekikei Gyoseki Hokokusho, 22, p.169 - 173, 2011/03

An accelerator mass spectrometry at Mutsu office, Japan Atomic Energy Agency (JAEA AMS MUTSU) was established in 1997 and the routine operation of radiocarbon measurement was started from 1999. The radiocarbon was measured by 1,053 samples in 2010, and the number of radiocarbon measurements reached 10,342 samples since the routine operation. This AMS has adopted the open door policy for the general users from the fiscal year of 2006 and various researches have been in progress by many users. In this presentation, I introduce the current status of JAEA AMS MUTSU.

Journal Articles

Status of JAEA-AMS-MUTSU

Tanaka, Takayuki; Kabuto, Shoji; Kinoshita, Naoki; Suzuki, Takashi; Kuwabara, Jun; Seki, Takeo

Dai-13-Kai AMS Shimpojiumu Hokokusho, p.129 - 132, 2011/01

An accelerator mass spectrometry at Aomori Research and Development Center, JAEA (JAEA-AMS-MUTSU) was established in 1997 and the routine operation of $$^{14}$$C and $$^{129}$$I measurement was started from 1999 and 2003, respectively. This AMS has adopted the open door policy for the general users from the fiscal year of 2006 and various researches have been in progress by many users. In this presentation, we introduce the status of JAEA-AMS-MUTSU. The total number of measurements has increased well for five years after the open door policy excluding in 2008. The reasons for the decrease in 2008 were that we had stopped the operation of AMS for about one and half months because the operation system of AMS was upgraded, and that we could not measure the $$^{14}$$C for several months because the amplifier of detector had broken. We had resolved this trouble and our AMS can measure smoothly both $$^{14}$$C and $$^{129}$$I.

Journal Articles

Status of JAEA-AMS-MUTSU at 2009-2010

Tanaka, Takayuki; Kabuto, Shoji; Kinoshita, Naoki; Suzuki, Takashi; Kuwabara, Jun; Seki, Takeo

Dai-23-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.113 - 116, 2010/11

An accelerator mass spectrometry at Aomori Research and Development Center, JAEA (JAEA-AMS-MUTSU) was established in 1997 and the routine operation of $$^{14}$$C and $$^{129}$$I measurement was started from 1999 and 2003, respectively. This AMS has adopted the open door policy for the general users from the fiscal year of 2006 and various researches have been in progress by many users. In this presentation, we introduce the status of JAEA-AMS-MUTSU in the fiscal year of 2009. The $$^{14}$$C and $$^{129}$$I were measured by 480 and 677 samples in the fiscal year of 2009, respectively. The total number of measurements has decreased by 716 samples from that of the fiscal year of 2008. The reasons for this decrease were that we had stopped the operation of AMS for about one and half months because the operation system of AMS was upgraded, and that we could not measure the $$^{14}$$C for several months because the amplifier of detector had broken. We had resolved this trouble and our AMS can measure smoothly both $$^{14}$$C and $$^{129}$$I.

Journal Articles

Development of virtual private network for JT-60SA CAD integration

Oshima, Takayuki; Fujita, Takaaki; Seki, Masami; Kawashima, Hisato; Hoshino, Katsumichi; Shibanuma, Kiyoshi; Verrecchia, M.*; Teuchner, B.*

Journal of Plasma and Fusion Research SERIES, Vol.9, p.620 - 624, 2010/08

For interface control and assembly, the CAD data will be exchanged and integrated in a new Data Base server installed at Naka for JT-60SA, where a common computer network efficiently connected between the Naka site for JAEA and the Garching site for F4E is needed to be established. To ensure the design environments, a VPN (Virtual Private Network) was introduced with CAD LAN on computer network physically-separated from JAEA intranet area and firewall. In July 2009, a new VPN connection between the Naka and Garching sites has been successfully demonstrated using IPSec-VPN technology with a commercial and cost-effective firewall/router for security. The VPN technology would provide a common platform for the development of remote experimentation techniques on JT-60SA between Rokkasho and Naka in collaboration with activities of the ITER Remote Experimentation Centre for the IFERC Project at Rokkasho.

Journal Articles

Development and achievements on the high power ECRF system in JT-60U

Moriyama, Shinichi; Kobayashi, Takayuki; Isayama, Akihiko; Terakado, Masayuki; Sawahata, Masayuki; Suzuki, Sadaaki; Yokokura, Kenji; Shimono, Mitsugu; Hasegawa, Koichi; Hiranai, Shinichi; et al.

Nuclear Fusion, 49(8), p.085001_1 - 085001_7, 2009/07

 Times Cited Count:16 Percentile:40.22(Physics, Fluids & Plasmas)

In the gyrotron development in JT-60U ECRF system, output power of 1.5 MW for 1 s has been achieved at 110 GHz. It is the world highest power oscillation $$>$$ 1 s. In addition to the carefully designed cavity and collector in view of thermal stress, an RF shield for the adjustment bellows, and a low-dielectric-loss DC break enabled this achievement. Power modulation technique by anode voltage control was improved to obtain high modulation frequency and 5 kHz has been achieved for NTM stabilizing experiments. Long pulse demonstration of 0.4 MW, 30 s injection to the plasma has been achieved with real time control of anode/cathode-heater. It has been confirmed that the temperature of cooled components were saturated and no evidence of damage were found. An innovative antenna having wide range of beam steering capability with linearly-moving-mirror concept has been designed for long pulse. Beam profile and mechanical strength analyses shows the feasibility of the antenna.

Journal Articles

Long pulse/high power ECRF system development in JT-60U

Moriyama, Shinichi; Kobayashi, Takayuki; Isayama, Akihiko; Terakado, Masayuki; Sawahata, Masayuki; Suzuki, Sadaaki; Yokokura, Kenji; Shimono, Mitsugu; Hasegawa, Koichi; Hiranai, Shinichi; et al.

Proceedings of 22nd IAEA Fusion Energy Conference (FEC 2008) (CD-ROM), 8 Pages, 2008/10

In the gyrotron development in JT-60U ECRF system, output power of 1.5 MW for 1 s has been achieved at 110 GHz. It is the world highest power oscillation $$>$$ 1 s. In addition to the carefully designed cavity and collector in view of thermal stress, an RF shield for the adjustment bellows, and a low-dielectric-loss DC break enabled this achievement. Power modulation technique by anode voltage control was improved to obtain high modulation frequency and 5 kHz has been achieved for NTM stabilizing experiments. Long pulse demonstration of 0.4 MW, 30 s injection to the plasma has been achieved with real time control of anode/cathode-heater. It has been confirmed that the temperature of cooled components were saturated and no evidence of damage were found. An innovative antenna having wide range of beam steering capability with linearly-moving-mirror concept has been designed for long pulse. Beam profile and mechanical strength analyses shows the feasibility of the antenna.

Journal Articles

Achievement of 1.5 MW, 1 s oscillation by the JT-60U gyrotron

Kobayashi, Takayuki; Moriyama, Shinichi; Seki, Masami; Sawahata, Masayuki; Terakado, Masayuki; Fujii, Tsuneyuki

Plasma and Fusion Research (Internet), 3, p.014_1 - 014_3, 2008/03

Gyrotrons are used for electron cyclotron heating (ECH) / current drive (ECCD) as high power millimeter wave sources in high performance plasma experiments. Pulse length from 0.1 to several seconds with high power is required in present tokamak experiments, such as JT-60U. However, 0.1 s oscillation had only been achieved in the power level of 1.5 MW. In JAEA, high power and long pulse oscillation experiments by using the latest JT-60U gyrotron have been tried to achieve power level of 1.5 MW and pulse length over 1 s. As a result, 1.5 MW/1 s oscillation has been successfully achieved by the fine optimization of operation parameters. In this paper, the first results of the oscillation experiment of 1.5 MW for 1 s and future plans of gyrotron improvements are described.

Journal Articles

Research and development of nuclear fusion

Ushigusa, Kenkichi; Seki, Masahiro; Ninomiya, Hiromasa; Norimatsu, Takayoshi*; Kamada, Yutaka; Mori, Masahiro; Okuno, Kiyoshi; Shibanuma, Kiyoshi; Inoue, Takashi; Sakamoto, Keishi; et al.

Genshiryoku Handobukku, p.906 - 1029, 2007/11

no abstracts in English

JAEA Reports

Behavior on O/M ratio for Am containing MOX fuel

Sato, Isamu; Seki, Takayuki*; Ishi, Yohei; Mondo, Kenji; Yoshimochi, Hiroshi; Tanaka, Kenya

JAEA-Research 2007-013, 63 Pages, 2007/03

JAEA-Research-2007-013.pdf:4.89MB

In air atmosphere, the weight of Am-MOX fuel relatively rapidly increased, which change rate strongly depended on the initial O/M ratio. The lower initial O/M ratio is, the higher the rate is. However, for the other MOX fuel containing little Am, the equivalent behavior have been observed, which indicated that not only Am but also the property of law material powder affected the behavior. The X-ray diffraction pattern change as time goes by was observed, which was a evidence that the O/M ratio change might arise from crystallographic one. The rate of O/M ratio change is a function of water vapor pressure in the atmosphere. If the water vapor pressure would is set to be quite low (ex. $$<$$ 1ppm), the O/M ratio change could effectively been avoided. On a model basis of Am(III) and U(V) existence, we could explain the O/M ratio dependence of the lattice parameter of Am-MOX fuel near O/M ratio, 2.00 better.

Journal Articles

Fabrication technology for MOX fuel containing AmO$$_{2}$$ by an in-cell remote process

Yoshimochi, Hiroshi; Ishi, Yohei; Seki, Takayuki*; Mondo, Kenji; Sekine, Shinichi*; Koyama, Shinichi

Saikuru Kiko Giho, (28), p.9 - 20, 2005/09

An in-cell remote fabrication technique has been developed for MOX fuel pellets containing 3 and 5% americium (Am-MOX) at the Alpha-gamma Facility (AGF) in O-arai Engineering Center. A series of fuel pellet and the pin fabrication apparatuses were systematically installed in hot cell to make fabrication flow easier. After cold run and some modifications, they were remotely controlled from a panel in the operation room outside the hot cell as much as possible. From a preliminary UO2 pellet test and consequently plutonium pellet fabrication run, actual range of ball milling time, pressing and sintering condition were focused for Am-MOX pellet fabrication. As the next step, moisturized atmosphere was found out to remove the heterogeneity structure of 5% Am-MOX pellet. Finally, we established an optimized fabrication condition of 5% Am-MOX pellet sintered at 1700$$^{circ}$$C for 3h in an atmosphere of 5% H2-95% Ar with total moisture of 2000 ppm. Moreover it is important that the atmosphere has to be changed to dry gas at 800$$^{circ}$$C during cool down.

JAEA Reports

Effect of Oxygen Potential on the Sintering behavior of MOX fuel containing Am

Miwa, Shuhei; Osaka, Masahiko; Yoshimochi, Hiroshi; Tanaka, Kenya; Seki, Takayuki*; Sekine, Shinichi*

JNC-TN9400 2005-023, 43 Pages, 2005/04

JNC-TN9400-2005-023.pdf:3.56MB

The effect of oxygen potential on the sintering behavior of MOX fuel containing Am (Am-MOX) was investigated. Green pellets of Am-MOX were prepared by a conventional powder metallurgical technique. For Am-MOX fuel pellets sintered at various oxygen potential conditions, density measurement, microstructural observation and elements analyses by EPMA were performed High density pellets having good structure were obtained due to oxygen potential change of sintering atmosphere from high oxygen potential to low oxygen potential at 800$$^{circ}$$C in the cooling process.For the pellets sintered at -520 kJ/mol, -390 kJ/mol and -340 kJ/mol, the sintered density increases with increase of oxygen potential up to -390 kJ/mol (threshold oxygen potential), then decreases above the threshold oxygen potential. This tendency is similar to that observed in the (U,Gd)O$$_{2 }$$ system. The differences of sintering behavior for Am-MOX pellets which were observed by changing the oxygen potential were attributable to the difference of pore structure, which was supposed to be caused by the valence state of Am in the oxides. On the other hands, the grain size of Am-MOX pellet sintered at -520 kJ/mol was almost the same as that at -390 kJ/mol. Homogeneous distribution of U, Pu and Am was obtained at pellets sintered both -520 and -390 kJ/mol in these sintering conditions. For the pellets sintered at 1500$$^{circ}$$C , 1600$$^{circ}$$C , 1700$$^{circ}$$C , the high dense pellets are obtained, therefore This results shows the the possibility of fabrication of good fuel pellets at lower temperature than 1700$$^{circ}$$C

JAEA Reports

Phase relation of (U,Pu,Am)O$$_{2-x}$$

Osaka, Masahiko; Miwa, Shuhei; Mondo, Kenji; Ozaki, Yoko; Ishi, Yohei; Yoshimochi, Hiroshi; Seki, Takayuki*; Sekine, Shinichi*; Ishida, Takashi*; Tanaka, Kenya

JNC-TN9400 2005-002, 40 Pages, 2005/03

JNC-TN9400-2005-002.pdf:2.43MB

An experimental investigation for the phase relation of (U,Pu,Am)O$$_{2-x}$$ was performed with XRD, ceramography and DTA. Although lattice parameter tended to increase with increases of Am content and O/M ratio, its slope differed from that of (U,Pu)O$$_{2-x}$$. A drastic structural change was observed around O/M=1.98. Besides, many DTA peaks, which could never be seen in the case of (U,Pu)O$$_{2-x}$$, were observed above O/M=1.98.These results were interpreted with a hypothesis that all Am were trivalent and equivalent amount of U became pentavalent. The dependence of lattice parameter on Am content could be expressed well by using a model with ionic radii of each element. Also the structural change around O/M=1.98 could be explained as caused by valence states of each element. It was concluded from these interpretation that all Am in (U,Pu,Am)O$$_{2-x}$$ were likely to exist as trivalent state.

Journal Articles

Investigation of causality in the H-L transition on the JFT-2M tokamak

*; *; *; *; *; *; *; Oikawa, Toshihiro; *; *; et al.

Fusion Energy 1996, p.885 - 890, 1997/05

no abstracts in English

Oral presentation

Fundamental properties of low-decontaminated Fuels, 5; Oxygen potentials of (Pu$$_{0.91}$$Am$$_{0.09}$$)O$$_{2-x}$$

Osaka, Masahiko; Mondo, Kenji; Ishi, Yohei; Tanaka, Kenya; Seki, Takayuki*; Kurosaki, Ken*; Uno, Masayoshi*; Yamanaka, Shinsuke*

no journal, , 

Oxygen potential of (Pu$$_{0.91}$$Am$$_{0.09}$$)O$$_{2-x}$$ were measured by thermogravimetry using H$$_{2}$$O/H$$_{2}$$ gas equiribrium, as a fundamental part of investigation on phase relation for low-decontaminated fuel.

53 (Records 1-20 displayed on this page)