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Journal Articles

Design for detecting recycling muon after muon-catalyzed fusion reaction in solid hydrogen isotope target

Okutsu, Kenichi*; Yamashita, Takuma*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.

Fusion Engineering and Design, 170, p.112712_1 - 112712_4, 2021/09

A muonic molecule which consists of two hydrogen isotope nuclei (deuteron (d) or tritium (t)) and a muon decays immediately via nuclear fusion and the muon will be released as a recycling muon, and start to find another hydrogen isotope nucleus. The reaction cycle continues until the muon ends up its lifetime of 2.2 $$mu$$s. Since the muon does not participate in the nuclear reaction, the reaction is so called a muon catalyzed fusion ($$mu$$CF). The recycling muon has a particular kinetic energy (KE) of the muon molecular orbital when the nuclear reaction occurs. Since the KE is based on the unified atom limit where distance between two nuclei is zero. A precise few-body calculation estimating KE distribution (KED) is also in progress, which could be compared with the experimental results. In the present work, we observed recycling muons after $$mu$$CF reaction.

Journal Articles

Time evolution calculation of muon catalysed fusion; Emission of recycling muons from a two-layer hydrogen film

Yamashita, Takuma*; Okutsu, Kenichi*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.

Fusion Engineering and Design, 169, p.112580_1 - 112580_5, 2021/08

A muon ($$mu$$) having 207 times larger mass of electron and the same charge as the electron has been known to catalyze a nuclear fusion between deuteron (d) and triton (t). These two nuclei are bound by $$mu$$ and form a muonic hydrogen molecular ion, dt$$mu$$. Due to the short inter-nuclear distance of dt$$mu$$, the nuclear fusion, d +t$$rightarrow alpha$$ + n + 17.6 MeV, occurs inside the molecule. This reaction is called muon catalyzed fusion ($$mu$$CF). Recently, the interest on $$mu$$CF is renewed from the viewpoint of applications, such as a source of high-resolution muon beam and mono-energetic neutron beam. In this work, we report a time evolution calculation of $$mu$$CF in a two-layered hydrogen isotope target.

Journal Articles

Fuel debris' air cooling analysis using a lattice Boltzmann method

Onodera, Naoyuki; Idomura, Yasuhiro; Kawamura, Takuma; Uesawa, Shinichiro; Yamashita, Susumu; Yoshida, Hiroyuki

Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 6 Pages, 2019/05

A dry method is one of practical methods for decommissioning the TEPCO's Fukushima Daiichi Nuclear Power Station. Japan Atomic Energy Agency (JAEA) has been evaluating the air cooling performance by using the JUPITER code. However, the JUPITER code requires a large computational cost to capture debris' structures. To accelerate such CFD analyses, we use the CityLBM code, which is based on the lattice Boltzmann method (LBM) and is highly optimized for GPUs. The CityLBM code is validated against free convective heat transfer experiments at JAEA, and the similar accuracy as the JUPITER code is confirmed regarding the prediction capability of heat transfer and the resulting temperature distributions. It is also shown that the elapse time of a CityLBM simulation on GPUs is reduced to 1/6 compared with that of the corresponding JUPITER simulation on CPUs with the same number of GPUs and CPUs. The results show that the LBM is promising for accelerating thermal convective simulations.

Journal Articles

Applicability of iron phosphate glass medium for loading NaCl originated from seawater used for cooling the stricken power reactors

Kobayashi, Hidekazu; Amamoto, Ippei; Yokozawa, Takuma; Yamashita, Teruo; Nagai, Takayuki; Kitamura, Naoto*; Takebe, Hiromichi*; Mitamura, Naoki*; Tsuzuki, Tatsuya*

Proceedings of 15th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2013) (CD-ROM), 6 Pages, 2013/09

no abstracts in English

Journal Articles

Behaviour of IPG waste forms bearing BaSO$$_{4}$$ as the dominant sludge constituent generated from the treatment of water used for cooling the stricken power reactors

Amamoto, Ippei; Kobayashi, Hidekazu; Yokozawa, Takuma; Yamashita, Teruo; Nagai, Takayuki; Kitamura, Naoto*; Takebe, Hiromichi*; Mitamura, Naoki*; Tsuzuki, Tatsuya*

Proceedings of 15th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2013) (CD-ROM), 8 Pages, 2013/09

The great amount of water used for cooling the stricken power reactors at Fukushima Dai-ichi has resulted in accumulation of "remaining water". As the remaining water is subsequently contaminated by FPs, etc., it is necessary to decontaminate it in order to reduce the volume of liquid radioactive waste and to reuse it again for cooling the reactors. Various techniques are being applied to remove FP, etc. and to make stable waste forms. One of the methods using the iron phosphate glass as a medium is being developed to stabilize the strontium-bearing sludge whose main component is BaSO$$_{4}$$. From the results hitherto, the iron phosphate glass is regarded as a potential medium for the target sludge.

Oral presentation

Radiation protection feature and research at Tokai reprocessing plant

Momose, Takumaro; Endo, Kuniaki; Ito, Yasuhisa; Yamashita, Tomoyuki; Namiki, Atsushi; Sanada, Yukihisa; Akiyama, Kiyomitsu; Takeishi, Minoru; Tago, Itaru; Furuta, Sadaaki

no journal, , 

The first reprocessing pilot plant in Japan (Tokai Reprocessing Plant; TRP) has been operated since 1977 at Nuclear Fuel Cycle Engineering Laboratories, JAEA. General radiation protection in TRP is performed with continuous monitoring and sampling methods. The continuous monitors measuring $$gamma$$-ray, neutron, particulate alpha and beta nuclides in the air are installed in the radiation controlled area as a central monitoring system to prevent from unnecessary exposure. Air and water effluents from the TRP are also monitored by continuous monitors or sampling methods to comply with regulations. In addition to this, environmental monitoring has been carried out to assess influences on public and environment by the plant operation. A feature of radiation protection and its recent relevant researches at TRP will be introduced in this presentation.

Oral presentation

Radiation management under circumstances of ventilation stop at the reprocessing plant; The Effect of radon progenies on airborne monitoring

Iijima, Nobuo; Sanada, Yukihisa; Yamashita, Tomoyuki; Momose, Takumaro

no journal, , 

no abstracts in English

Oral presentation

Radiation management under circumstances of ventilation stop at the reprocessing plant; The Effect of radon progenies on airborne monitoring

Hokama, Tomonori; Iijima, Nobuo; Sanada, Yukihisa; Yamashita, Tomoyuki; Momose, Takumaro

no journal, , 

no abstracts in English

Oral presentation

Development of smear measuring method by liquid scintillation counter

Nakamura, Keisuke; Iijima, Nobuo; Yamashita, Tomoyuki; Shiba, Kozo; Momose, Takumaro

no journal, , 

no abstracts in English

Oral presentation

Radiological reference lebel at Tokai Reprocessing Plant under the influence by accident of Fukushima Daiichi Nuclear Power Plant

Hokama, Tomonori; Sanada, Yukihisa; Yamashita, Tomoyuki; Shiba, Kozo; Momose, Takumaro

no journal, , 

Fukushima Daiichi Nuclear Power Plant released radioactive isotope accompany the Great Eastern Japan Earthquake. The radioactive isotope came at Tokai Reprocessing Plant, and their influence cannot be disregarded. Radiological control in reprocessing plant divided degree of influence into 3 situation, so we carried out radiological control depends on each situation.

Oral presentation

Behavior of cesium in the soil by heating

Yokozawa, Takuma; Kobayashi, Hidekazu; Yamashita, Teruo; Nagai, Takayuki; Tokizawa, Takayuki; Naganuma, Masaki; Aoki, Katsumi

no journal, , 

no abstracts in English

Oral presentation

Applicability of vitrification to the secondary waste produced by treatment of the contaminated water; Study on vitrification to the spent zeolite

Kobayashi, Hidekazu; Yokozawa, Takuma; Yamashita, Teruo; Nagai, Takayuki; Amamoto, Ippei; Ayame, Yasuo

no journal, , 

no abstracts in English

Oral presentation

Fundamental study on immobilization of sludge generated from treatment of remaining water used for cooling of the stricken power reactors

Amamoto, Ippei; Kobayashi, Hidekazu; Yokozawa, Takuma; Yamashita, Teruo; Nagai, Takayuki; Suzuki, Yoshikazu*; Takebe, Hiromichi*; Mitamura, Naoki*; Tsuzuki, Tatsuya*

no journal, , 

The great amount of water used for cooling the stricken reactors at Fukushima Dai-ichi Nuclear Power Plant following the earthquake and tsunami of 11 March 2011 had resulted in accumulation of "remaining water" in some buildings. From public announcements, it seems likely the decontamination process of La Hague reprocessing plant would be employed as one of the treatment processes for the remaining water contaminated by FPs such as Cs, Sr, etc.. Based on literature study, Cs would precipitate with ferrocyanide compound as well as Sr with BaSO$$_{4}$$ by applying the above-mentioned process. In this study, BaSO$$_{4}$$ as the simulated sludge was loaded into the iron phosphate glass (IPG) medium under different melting temperature. Based on the results, the performance of IPG containing BaO (decomposed from BaSO$$_{4}$$) improved with increase loading of BaO up to 48 mol% at lower melting temperature.

Oral presentation

Applicability of vitrification method for waste generated from treatment of contaminated water, 3; Preliminary experiment on vitrification of the sludge

Amamoto, Ippei; Yokozawa, Takuma; Yamashita, Teruo; Nagai, Takayuki; Nakamura, Hirotaka*; Takebe, Hiromichi*; Mitamura, Naoki*; Tsuzuki, Tatsuya*; Kobayashi, Hidekazu

no journal, , 

no abstracts in English

Oral presentation

Investigation of coagulated glass included noble metal compounds by Raman spectroscopy

Nagai, Takayuki; Oyama, Koichi; Kobayashi, Hidekazu; Morikawa, Yo; Yokozawa, Takuma; Nakajima, Masayoshi; Yamashita, Teruo; Amamoto, Ippei

no journal, , 

no abstracts in English

Oral presentation

Applicability of vitrification method for waste generated from treatment of contaminated water, 2; Outline of sludge vitrification and selection of glass medium

Amamoto, Ippei; Kobayashi, Hidekazu; Yokozawa, Takuma; Yamashita, Teruo; Nagai, Takayuki; Suzuki, Yoshikazu*; Takebe, Hiromichi*; Mitamura, Naoki*; Tsuzuki, Tatsuya*

no journal, , 

no abstracts in English

Oral presentation

Applicability of vitrification method for waste generated from treatment of contaminated water, 1; Preliminary experiment on vitrification of the spent zeolite

Yokozawa, Takuma; Kobayashi, Hidekazu; Yamashita, Teruo; Nagai, Takayuki; Amamoto, Ippei

no journal, , 

no abstracts in English

Oral presentation

Applicability of vitrification to the secondary waste generated from treatment of the contaminated water

Kobayashi, Hidekazu; Yokozawa, Takuma; Yamashita, Teruo; Nagai, Takayuki; Amamoto, Ippei

no journal, , 

no abstracts in English

Oral presentation

Applicability of vitrification method for waste generated from treatment of contaminated water, 5; Fundamental experiment on vitrification of NaCl by the IPG medium

Kobayashi, Hidekazu; Amamoto, Ippei; Yokozawa, Takuma; Yamashita, Teruo; Nagai, Takayuki; Kitamura, Naoto*; Takebe, Hiromichi*; Mitamura, Naoki*; Tsuzuki, Tatsuya*

no journal, , 

no abstracts in English

Oral presentation

Applicability of vitrification method for waste generated from treatment of contaminated water, 4; Fundamental experiment on vitrification of BaSO$$_{4}$$ by the IPG medium

Amamoto, Ippei; Kobayashi, Hidekazu; Yokozawa, Takuma; Yamashita, Teruo; Nagai, Takayuki; Kitamura, Naoto*; Takebe, Hiromichi*; Mitamura, Naoki*; Tsuzuki, Tatsuya*

no journal, , 

no abstracts in English

39 (Records 1-20 displayed on this page)