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JAEA Reports

Tritium removal of heavy water system and helium system in FUGEN

Takiya, Hiroaki; Kadowaki, Haruhiko; Matsushima, Akira; Matsuo, Hidehiko; Ishiyama, Masahiro; Aratani, Kenta; Tezuka, Masashi

JAEA-Technology 2020-001, 76 Pages, 2020/05

JAEA-Technology-2020-001.pdf:6.06MB

Advanced Thermal Reactor (ATR) FUGEN was operated for about 25 years, and now has been proceeding decommissioning after the approval of the decommissioning plan in Feb. 2008. The reactor, heavy water system and helium system are contaminated by tritium because of neutron absorption of heavy water, which is a moderator. Before dismantling these facilities, it is necessary to remove tritium from them for not only reducing the amount of tritium released to surrounding environment and the risk of internal exposure by tritium but also ensuring the workability. In first phase of decommissioning (Heavy Water and Other system Decontamination Period), tritium decontamination of the reactor, heavy water system and helium system started in 2008 and completed in 2018. This report shows the results of tritium decontamination of the reactor, heavy water system and helium system.

Journal Articles

Status of decommissioning of FUGEN Decommissioning Engineering Center

Takiya, Hiroaki; Aratani, Kenta; Awatani, Yuto; Ishiyama, Masahiro; Tezuka, Masashi; Mizui, Hiroyuki

Dekomisshoningu Giho, (59), p.2 - 12, 2019/03

FUGEN Decommissioning Engineering Center received the approval of the decommissioning program in 2008, and we have been progressing the decommissioning. The first phase of decommissioning (Heavy Water and Other system Decontamination Period) finished in May 2018, and FUGEN has entered into the second phase of decommissioning (Reactor Periphery Facilities Dismantling Period). This report outlines the results obtained in the first phase of decommissioning of FUGEN.

Journal Articles

In situ X-ray absorption fine structure studies of amorphous and crystalline polyoxovanadate cluster cathodes for lithium batteries

Wang, H.*; Idobe, Jin*; Matsumura, Daiju; Yoshikawa, Hirofumi*

Journal of Solid State Electrochemistry, 22(7), p.2067 - 2071, 2018/07

 Times Cited Count:10 Percentile:36.89(Electrochemistry)

Journal Articles

Theoretical model analysis of $$(d,xn)$$ reactions on $$^7$$Li at 25, 40, and 102 MeV

Sadamatsu, Hiroki*; Nakayama, Shinsuke; Watanabe, Yukinobu*; Iwamoto, Osamu; Ogata, Kazuyuki*

JAEA-Conf 2017-001, p.135 - 140, 2018/01

In recent years, the demand for intense neutron sources has been increasing in various applications such as nuclear transmutation of high-level radioactive waste and medical radioisotopes production. Deuteron accelerator-based neutron sources are promised as one of the candidates. Therefore, we have developed a code system dedicated for the deuteron-induced reactions, called DEURACS. In the present work, we focus on deuteron-induced neutron production from $$^7$$Li target. The calculated double differential cross sections for $$(d,xn)$$ reactions at incident energies of 25, 40, and 102 MeV are compared with the measured ones, and the applicability of DEURACS is discussed.

JAEA Reports

Verification of alternative dew point hygrometer for CV-LRT in Monju

Ichikawa, Shoichi; Chiba, Yusuke; Ono, Fumiyasu; Hatori, Masakazu; Kobayashi, Takanori; Uekura, Ryoichi; Hashiri, Nobuo*; Inuzuka, Taisuke*; Kitano, Hiroshi*; Abe, Hisashi*

JAEA-Research 2016-021, 32 Pages, 2017/02

JAEA-Research-2016-021.pdf:5.0MB

In order to reduce the influence on a plant schedule of the MONJU by the maintenance of dew point hygrometers, The JAEA examined a capacitance type dew point hygrometer as an alternative dew point hygrometer for a lithium-chloride type dew point hygrometer which had been used at the CV-LRT in the MONJU. As a result of comparing a capacitance type dew point hygrometer with a lithium-chloride type dew point hygrometer at the CV-LRT (Atmosphere: nitrogen, Testing time: 24 hours), there weren't significant difference between a capacitance type dew point hygrometer and a lithium-chloride type dew point hygrometer. As a result of comparing a capacitance dew point hygrometer with a high-mirror-surface type dew point hygrometer for long term verification (Atmosphere: air, Testing time: 24 months), the JAEA confirmed that a capacitance type dew point hygrometer satisfied the instrument specification ($$pm$$2.04$$^{circ}$$C) required by the JEAC4203-2008.

Journal Articles

Additional information to report on site tour of the Fukushima Daiichi Nuclear Power Station

Suto, Toshiyuki

Genshiryoku, hoshasen Bukaiho (Internet), (19), P. 15, 2016/12

The Tritiated Water Task Force under METI's Committee on Countermeasures for Contaminated Water Treatment for Fukushima Daiichi Nuclear Power Plant (1F) reported that the option of post-dilution offshore release could dispose the tritiated water at a smallest cost in the shortest amount of time. The amount of tritium in the contaminated water at 1F was compared with ones released from nuclear power plants and reprocessing plants as some help for grasping its level of magnitude.

Journal Articles

Report on site tour of the Fukushima Nuclear Power Station

Suto, Toshiyuki

Gijutsushi, 28(11), p.8 - 11, 2016/11

Five years have passed since the accident of the Fukushima Daiichi Nuclear Power Station. The Nuclear and Radiation section of the Institute of Professional Engineers hosted a site tour of the plant to make themselves sure what is going on in it and to disseminate information about it. The conditions of landscape during traveling between the gathering place and the plant, each reactor, contaminated water treatment, site, and work environment improvement will be reported.

Journal Articles

Nitrogen hot trap design and manufactures for lithium test loop in IFMIF/EVEDA project

Wakai, Eiichi; Watanabe, Kazuyoshi*; Ito, Yuzuru*; Suzuki, Akihiro*; Terai, Takayuki*; Yagi, Juro*; Kondo, Hiroo; Kanemura, Takuji; Furukawa, Tomohiro; Hirakawa, Yasushi; et al.

Plasma and Fusion Research (Internet), 11, p.2405112_1 - 2405112_4, 2016/11

BB2015-1982.pdf:2.03MB

Journal Articles

Study on pretreatment methods using a rapid combustion apparatus for the analyses of Organically Bound Tritium (OBT) in environmental samples

Manabe, Sachi; Matsubara, Natsumi; Saegusa, Jun; Takeishi, Minoru

KEK Proceedings 2016-8, p.281 - 285, 2016/10

no abstracts in English

Journal Articles

R-matrix analysis for the $$^8$$Be system and features in the p+$$^7$$Li reaction over resonance region

Kunieda, Satoshi

EPJ Web of Conferences, 122, p.08003_1 - 08003_13, 2016/06

The p+$$^7$$Li reaction is highly relevant to accelerator applications and fundamental physics. Therefore, those reaction cross-sections should be quantitatively known over the relevant energy range. However, in-depth theoretical/evaluation works have not necessarily been reported despite a number of experimental data which have been measured over the years. In this work, a multi-channel R-matrix analysis is carried out for $$^8$$Be system to know explicit natures in p+$$^7$$Li reaction over the resonance region. Present analysis reveals contribution from each $$J^{pi}$$ to the cross-sections and impact from direct process.

Journal Articles

Tritium decontamination of contaminated system with tritiated heavy water by drying treatment

Kadowaki, Haruhiko; Matsushima, Akira; Nakajima, Yoshiaki

Proceedings of 24th International Conference on Nuclear Engineering (ICONE-24) (DVD-ROM), 6 Pages, 2016/06

Advanced thermal reactor "FUGEN" is a heavy water-moderated boiling light water-cooled pressure tube-type reactor. Because tritium had been generated in the heavy water during the reactor operation, the heavy water system and helium system were contaminated by tritium. The chemical form of the tritium was water molecule in FUGEN. Air-through drying and vacuum drying were applied to the system drying, and it was demonstrated that both methods were effective for drying treatment of heavy water in system. Helium system, low-contamination and non inclusion, could finish the vacuum drying rapidly. However, Heavy water purification system needed long period for drying treatment. The result showed that it needed long period to dry up if the objects include the adsorbent of water such as alumina pellet, resin and silica gel. But it can be accelerated by replacement absorbed heavy water to light water from the result of drying treatment of the rotary type dehumidifier.

Journal Articles

Chemical reaction of lithium with room temperature atmosphere of various humidities

Furukawa, Tomohiro; Hirakawa, Yasushi; Kondo, Hiroo; Kanemura, Takuji; Wakai, Eiichi

Fusion Engineering and Design, 98-99, p.2138 - 2141, 2015/10

BB2014-0426.pdf:0.49MB

 Times Cited Count:5 Percentile:45.16(Nuclear Science & Technology)

In the International Fusion Materials Irradiation Facility (IFMIF), a back plate of the target assembly will be exchanged during the in-service period. During the works, the lithium components will react chemically with the surrounding atmosphere. In this research, the chemical reaction of lithium in air, oxygen and nitrogen containing variable humidity at room temperature has been investigated to estimate the chemical reaction during the exchange works.

Journal Articles

Hydrophobic platinum honeycomb catalyst to be used for tritium oxidation reactors

Iwai, Yasunori; Kubo, Hitoshi*; Oshima, Yusuke*; Noguchi, Hiroshi*; Edao, Yuki; Taniuchi, Junichi*

Fusion Science and Technology, 68(3), p.596 - 600, 2015/10

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

We have newly developed the hydrophobic platinum honeycomb catalysts applicable to tritium oxidation reactor since the honeycomb-shape catalyst can decrease the pressure drop. Two types of hydrophobic honeycomb catalyst have been test-manufactured. One is the hydrophobic platinum catalyst on a metal honeycomb. The other is the hydrophobic platinum catalyst on a ceramic honeycomb made of silicon carbide. The fine platinum particles around a few nanometers significantly improve the catalytic activity for the oxidation tritium at a tracer concentration. The hydrogen concentration in the gaseous feed slightly affects the overall reaction rate constant for hydrogen oxidation. Due to the competitive adsorption of hydrogen and water molecules on platinum surface, the overall reaction rate constant has the bottom value. The hydrogen concentration for the bottom value is 100 ppm under the dry feed gas. We have experimentally confirmed the activity of these honeycomb catalysts is as good as that of pellet-shape hydrophobic catalyst. The results support the hydrophobic honeycomb catalysts are applicable to tritium oxidation reactor.

Journal Articles

Catalyst technology of Tanaka Kikinzoku Kogyo

Kubo, Hitoshi*; Oshima, Yusuke*; Iwai, Yasunori

JETI, 63(10), p.33 - 36, 2015/09

Tanaka Kikinzoku Kogyo provides a broad range of precious metals products and technologies. Tanaka Kikinzoku Kogyo and Japan Atomic Energy Agency have jointly developed a new method of manufacturing catalysts involving hydrophobic processing with an inorganic substance base. As a result, previous technological issues were able to be solved with the development of a catalyst that exhibited no performance degradation in response to radiation application of 530 kGy, a standard for radiation resistance, and maintenance of thermal stability at over 600$$^{circ}$$C, which is much higher than the 70$$^{circ}$$C temperature that is normally used. The application of this catalyst to the liquid phase catalytic exchange process is expected to overcome significant technological hurdles with regards to improving the reliability and efficiency of systems for collecting tritium from tritiated water. It is also anticipated that the hydrophobic platinum catalyst manufacturing technology used for this catalyst could be applied to a wide range of fields other than nuclear fusion research. It was verified that if applied to a hydro oxidation catalyst, hydrogen could be efficiently oxidized, even at room temperature. This catalyst can also contribute to improving safety at non-nuclear plants that use hydrogen in general by solving the aforementioned vulnerability issue.

Journal Articles

Development of hydrophobic platinum catalyst for the effective collection of tritium in fusion plants

Iwai, Yasunori; Kubo, Hitoshi*; Oshima, Yusuke*

Isotope News, (736), p.12 - 17, 2015/08

We have successfully developed a new hydrophobic platinum catalyst for collecting tritium at nuclear fusion reactors. Catalysts used to collect tritium are called hydrophobic precious metal catalysts. In Japan, hydrophobic precious metal catalysts manufactured from polymers have been used for heavy water refinement.However, this catalyst has issues related to embrittlement to radiation and thermal stability. These technological issues needed to be solved to allow for its application to nuclear fusion reactors requiring further enrichment from highly-concentrated tritiated water. We developed a new method of manufacturing catalysts involving hydrophobic processing with an inorganic substance base. As a result, previous technological issues were able to be solved with the development of a catalyst that exhibited no performance degradation in response to radiation application of 530kGy, a standard for radiation resistance, and maintenance of thermal stability at over 600$$^{circ}$$C, which is much higher than the 70$$^{circ}$$C temperature that is normally used. The catalyst created with this method was also confirmed to have achieved the world's highest exchange efficiency, equivalent to 1.3 times the previously most powerful efficiency. The application of this catalyst to the liquid phase catalytic exchange process is expected to overcome significant technological hurdles with regards to improving the reliability and efficiency of systems for collecting tritium from tritiated water.

Journal Articles

Successful development of a new catalyst for efficiently collecting tritium; A Breakthrough toward realization of fusion reactors

Iwai, Yasunori; Kubo, Hitoshi*; Oshima, Yusuke*

Kagaku, 70(5), p.35 - 40, 2015/05

We have successfully developed a new hydrophobic platinum catalyst for collecting tritium at nuclear fusion reactors. Catalysts used to collect tritium are called hydrophobic precious metal catalysts. In Japan, hydrophobic precious metal catalysts manufactured from polymers have been used for heavy water refinement. However, this catalyst has issues related to embrittlement to radiation and thermal stability. These technological issues needed to be solved to allow for its application to nuclear fusion reactors requiring further enrichment from highly-concentrated tritiated water. We developed a new method of manufacturing catalysts involving hydrophobic processing with an inorganic substance base. As a result, previous technological issues were able to be solved with the development of a catalyst that exhibited no performance degradation in response to radiation application of 530 kGy, a standard for radiation resistance, and maintenance of thermal stability at over 600$$^{circ}$$C, which is much higher than the 70$$^{circ}$$C temperature that is normally used. The catalyst created with this method was also confirmed to have achieved the world's highest exchange efficiency, equivalent to 1.3 times the previously most powerful efficiency. The application of this catalyst to the liquid phase catalytic exchange process is expected to overcome significant technological hurdles with regards to improving the reliability and efficiency of systems for collecting tritium from tritiated water.

Journal Articles

News from Broader Approach activities, 53

Ishii, Yasutomo; Matsunaga, Go; Okumura, Yoshikazu

Purazuma, Kaku Yugo Gakkai-Shi, 91(2), p.161 - 162, 2015/02

Success of the first beam of injector for IFMIF prototype accelerator, accomplishment of liquid Lithium Target validation test of the IFMIF/EVEDA and the progress of Satellite Tokamak (JT-60SA) were reported. The IFMIF/EVEDA project are performed in International Fusion Energy Research Center at Rokkasho under the BA agreement, installation and adjustment of injector for IFMIF accelerator were completed and the adjustment beam test has started from Nov. 2014. For the engineering validation test, formability of the Lithium Target which become the neutron source, the Lithium Test Loop of real scale was fabricated in Oarai and test has been conducted for 2 years. At the end of Oct. 2014, made an exceeding achievement and successfully concluded. In the construction of JT-60SA at Naka, the design of each part has been performing with the 3D CAD soft CATIA. The update with previous state discloses on JT60-SA HP. To disseminate information to the domestic community a major event in the BA activities.

Journal Articles

Status of development of Lithium Target Facility in IFMIF/EVEDA project

Wakai, Eiichi; Kondo, Hiroo; Kanemura, Takuji; Hirakawa, Yasushi; Furukawa, Tomohiro; Hoashi, Eiji*; Fukada, Satoshi*; Suzuki, Akihiro*; Yagi, Juro*; Tsuji, Yoshiyuki*; et al.

Proceedings of Plasma Conference 2014 (PLASMA 2014) (CD-ROM), 2 Pages, 2014/11

In the IFMIF/EVEDA (International Fusion Materials Irradiation Facility/ Engineering Validation and Engineering Design Activity), the validation tests of the EVEDA lithium test loop with the world's highest flow rate of 3000 L/min was succeeded in generating a 100 mm-wide and 25 mm-thick free-surface lithium flow steadily under the IFMIF operation condition of a high-speed of 15 m/s at 250$$^{circ}$$C in a vacuum of 10 $$^{-3}$$ Pa. Some excellent results of the recent engineering validations including lithium purification, lithium safety, and remote handling technique were obtained, and the engineering design of lithium facility was also evaluated. These results will advance greatly the development of an accelerator-based neutron source to simulate the fusion reactor materials irradiation environment as an important key technology for the development of fusion reactor materials.

Journal Articles

Evaluation of residual tritium in stainless steel irradiated at SINQ target 3

Kikuchi, Kenji; Nakamura, Hirofumi; Tsujimoto, Kazufumi; Kobayashi, Kazuhiro; Yokoyama, Sumi; Saito, Shigeru; Yamanishi, Toshihiko

Journal of Nuclear Materials, 356(1-3), p.157 - 161, 2006/09

 Times Cited Count:5 Percentile:60.37(Materials Science, Multidisciplinary)

A high-energy proton of 580MeV at SINQ target generates almost all constituents through spallation process with hydrogen and helium gases. For the SINQ target hydrogen and helium are generated to hundreds appm H and tens appm He, respectively. However, tritium gas production has not been yet reported. Evaluation of tritium gas generation in the specimens of target 3 was done by calculation. Results were compared with gamma spectrum measurement. Residual tritium measurement was carried by the thermal desorption method. It is found that a release of tritium began over 250$$^{circ}$$C and material included 4 MBq/g. The ratio of residual tritium to generated one is estimated to be less than 20%.

Journal Articles

Operation scenarios and requirements for fuel processing in future fusion reactor facilities; Hydrogen isotope separation as a key process for fuel recycle and safety

Ohira, Shigeru; Yamanishi, Toshihiko; Hayashi, Takumi

Journal of Nuclear Science and Technology, 43(4), p.354 - 360, 2006/04

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

In this paper, expected operation scenarios for ITER and future fusion reactors from a viewpoint of an integrated isotope processing in a future D-T fusion rector are provided with comparisons of requirements for system design attributed to the operation scenarios, safety requirements, etc. Most of the basic requirements for fuel process of a D-T fusion reactor facility common are the same, but the design requirements coming from the individual operation scenarios of ITER and future demo reactors will differ. The system design requirements of the tritium plant taking care of various operations of ITER and a demo reactor are examined and compared. Due to the increase of tritium concentration in the coolant of a demo reactor by tritium permeation in the structural material of the in-vessel components operated at a temperature higher than that of ITER detritiation of coolant will be getting more important. Some important key parameters related to hydrogen isotope processing in future fusion reactors will be discussed.

797 (Records 1-20 displayed on this page)