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JAEA Reports

Manufacture of substitutive assemblies for MONJU reactor decommissioning

Sakakibara, Hiroshi; Aoki, Nobuhiro; Muto, Masahiro; Otabe, Jun; Takahashi, Kenji*; Fujita, Naoyuki*; Hiyama, Kazuhiko*; Suzuki, Hirokazu*; Kamogawa, Toshiyuki*; Yokosuka, Toru*; et al.

JAEA-Technology 2020-020, 73 Pages, 2021/03

JAEA-Technology-2020-020.pdf:8.26MB

The decommissioning is currently in progress at the prototype fast breeder reactor Monju. Fuel assemblies will be taken out of its core for the first step of the great task. Fuel assemblies stand on their own spike plugged into a socket on the core support plate and support with adjacent assemblies through their housing pads each other, resulting in steady core structure. For this reason, some substitutive assemblies are necessary for the purpose of discharging the fuel assemblies of the core. Monju side commissioned, therefore, Plutonium Fuel Development Center to manufacture the substitutive assemblies and the Center accepted it. This report gives descriptions of design, manufacture, and shipment in regard to the substitutive assemblies.

Journal Articles

Origin of magnetovolume effect in a cobaltite

Miao, P.*; Tan, Z.*; Lee, S. H.*; Ishikawa, Yoshihisa*; Torii, Shuki*; Yonemura, Masao*; Koda, Akihiro*; Komatsu, Kazuki*; Machida, Shinichi*; Sano, Asami; et al.

Physical Review B, 103(9), p.094302_1 - 094302_18, 2021/03

 Times Cited Count:2 Percentile:17.84(Materials Science, Multidisciplinary)

The layered perovskite PrBaCo$$_{2}$$O$$_{5.5}$$ demonstrates a strong negative thermal expansion (NTE) which holds potential for being fabricated into composites with zero thermal expansion. The NTE was found to be intimately associated with the spontaneous magnetic ordering, known as magneto-volume effect (MVE). Here we report with compelling evidences that the continuous-like MVE in PrBaCo$$_{2}$$O$$_{5.5}$$ is intrinsically of discontinuous character, originating from an magnetoelectric transition from an antiferromagnetic insulating large-volume (AFILV) phase to a ferromagnetic less-insulating small-volume (FLISV) phase. Furthermore, the magnetoelectric effect (ME) shows high sensitivity to multiple external stimuli such as temperature, carrier doping, hydrostatic pressure, magnetic field etc. In contrast to the well-known ME such as colossal magnetoresistance and multi-ferroic effect which involve symmetry breaking of crystal structure, the ME in the cobaltite is purely isostructural. Our discovery provides a new path way to realizing the ME as well as the NTE, which may find applications in new techniques.

Journal Articles

Quantum paramagnet near spin-state transition

Tomiyasu, Keisuke*; Ito, Naoko*; Okazaki, Ryuji*; Takahashi, Yuki*; Onodera, Mitsugi*; Iwasa, Kazuaki*; Nojima, Tsutomu*; Aoyama, Takuya*; Ogushi, Kenya*; Ishikawa, Yoshihisa*; et al.

Advanced Quantum Technologies (Internet), 1(3), p.1800057_1 - 1800057_7, 2018/12

Spin-state transition, also known as spin crossover, plays a key role in diverse systems. In theory, the boundary range between the low- and high-spin states is expected to enrich the transition and give rise to unusual physical states. However, no compound that realizes a nearly degenerate critical range as the ground state without requiring special external conditions has yet been experimentally identified. This study reports that the Sc substitution in LaCoO3 destabilizes its nonmagnetic low-spin state and generates an anomalous paramagnetic state accompanied by the enhancement of transport gap and magneto-lattice-expansion as well as the contraction of Co-O distance with the increase of electron site transfer. These phenomena are not well described by the mixture of conventional low- and high-spin states, but by their quantum superposition occurring on the verge of a spin-state transition.

Journal Articles

Performance of a remotely located muon radiography system to identify the inner structure of a nuclear plant

Fujii, Hirofumi*; Hara, Kazuhiko*; Hashimoto, Shugo*; Ito, Fumiaki*; Kakuno, Hidekazu*; Kim, S.*; Kochiyama, Mami; Nagamine, Kanetada*; Suzuki, Atsuto*; Takada, Yoshihisa*; et al.

Progress of Theoretical and Experimental Physics (Internet), 2013(7), p.073C01_1 - 073C01_20, 2013/07

 Times Cited Count:26 Percentile:76.73(Physics, Multidisciplinary)

Journal Articles

Hydrogen concentration behavior in the IHTS of Monju

Ito, Kazuhiro; Tanabe, Hiromi; Kaneko, Yoshihisa; Kagota, Eiichi; Takahashi, Yasuo

Proceedings of 2013 International Congress on Advances in Nuclear Power Plants (ICAPP 2013) (USB Flash Drive), 10 Pages, 2013/04

The Monju is equipped with two types of hydrogen-meters to detect water leakage in steam generators. Since they are so highly-sensitive as to detect minor water leak from a steam generator tube, they sometimes detect hydrogen concentration increases at plant operational condition changes such as start-up without any water leak. No water leak was experienced during one year operation of the Startup Test up to 40% in 1995, although hydrogen concentration sometimes increased at plant operational condition changes. The H behavior of Monju IHTS during the previous Startup Test was examined and the following knowledge was obtained: The in-sodium H behaves in parallel with the IHTS sodium temperature. In-cover-gas H behavior is more complicated and sensitive to plant operational condition changes such as plant load changes than the in-sodium one. Both types of H-meters underwent a certain degree of zero level drift during one year operation.

Journal Articles

SR-PES and STM observation of metastable chemisorption state of oxygen on Si(110)-16$$times$$2 surface

Yamamoto, Yoshihisa*; Togashi, Hideaki*; Kato, Atsushi*; Takahashi, Yuya*; Konno, Atsushi*; Teraoka, Yuden; Yoshigoe, Akitaka; Asaoka, Hidehito; Suemitsu, Maki*

Applied Surface Science, 254(19), p.6232 - 6234, 2008/07

 Times Cited Count:4 Percentile:21.85(Chemistry, Physical)

The room temperature adsorbed state of oxygen molecules on Si(110)-16$$times$$2 surface and the structural change after a mild annealing has been investigated by synchrotron radiation photoemission spectroscopy. As a result, despite the very small dosage of oxygen, Si$$^{2+}$$ and Si$$^{3+}$$ components already appear in addition to Si$$^{1+}$$. This is likely to be caused by a selective adsorption of O$$_{2}$$ molecules into the vicinity of already oxidized sites. After annealing, we found that binding energy of Si$$^{2+}$$ and Si$$^{3+}$$ increase and approach to their corresponding peak positions of a thermally-grown oxide, and this increase indicates relaxation of the Si-O bond length and Si-O-Si bond angle of metastable oxygen atoms.

Journal Articles

XPS and STM studies on initial oxidation of Si(110)-16$$times$$2

Suemitsu, Maki*; Togashi, Hideaki*; Kato, Atsushi*; Takahashi, Yuya*; Konno, Atsushi*; Yamamoto, Yoshihisa*; Teraoka, Yuden; Yoshigoe, Akitaka; Asaoka, Hidehito

Materials Research Society Symposium Proceedings, Vol.996, p.19 - 25, 2007/00

From its high hole mobility, as well as its inevitable usage as an active layer in multi-gated FETs, Si(110) surface is expected to play a crucial role in the next generation CMOS devices. We have investigated the initial oxidation of Si(110) surface by using SR-XPS and STM. Reflecting its atomistic structure of the 16$$times$$2 reconstruction, initial oxidation of Si(110) surface shows a unique behavior which is not observed on other surfaces like (111) and (001).

Journal Articles

Optimization for SEU/SET immunity on 0.15 $$mu$$m fully depleted CMOS/SOI digital logic devices

Makihara, Akiko*; Asai, Hiroaki*; Tsuchiya, Yoshihisa*; Amano, Yukio*; Midorikawa, Masahiko*; Shindo, Hiroyuki*; Kuboyama, Satoshi*; Onoda, Shinobu; Hirao, Toshio; Nakajima, Yasuhito*; et al.

Proceedings of 7th International Workshop on Radiation Effects on Semiconductor Devices for Space Application (RASEDA-7), p.95 - 98, 2006/10

no abstracts in English

Journal Articles

Preparation of acid deficient solutions of uranyl nitrate and thorium nitrate by steam denitration

; Takahashi, Yoshihisa

Journal of Nuclear Science and Technology, 33(2), p.147 - 151, 1996/02

 Times Cited Count:1 Percentile:14.44(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Preparation of high density(Th,U)O$$_{2}$$ pellets by sol-gel microsphere pelletization and 1300$$^{circ}$$C air sintering

; Takahashi, Yoshihisa

Journal of Nuclear Materials, 217, p.127 - 137, 1994/00

 Times Cited Count:14 Percentile:75.32(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Effect of heating atmosphere on densification of sol-gel (Th,U)O$$_{2}$$ microspheres

; Takahashi, Yoshihisa

Journal of Nuclear Materials, 207, p.255 - 265, 1993/00

 Times Cited Count:6 Percentile:55.97(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Sintering behavior of sol-gel (Th,U)O$$_{2}$$ microspheres

; Takahashi, Yoshihisa

Journal of Nuclear Materials, 189, p.134 - 140, 1992/00

 Times Cited Count:3 Percentile:35.32(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Preparation of ThO$$_{2}$$ pellets by sol-gel microsphere pelletization

; Takahashi, Yoshihisa

Journal of Nuclear Materials, 189, p.72 - 78, 1992/00

 Times Cited Count:5 Percentile:48.18(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Improved mercury-pycnometry for measuring accurate volumes of solid materials

; Takahashi, Yoshihisa

Meas. Sci. Technol., 3, p.270 - 274, 1992/00

 Times Cited Count:7 Percentile:68.47(Engineering, Multidisciplinary)

no abstracts in English

Journal Articles

Further study on sintering behavior of sol-gel ThO$$_{2}$$ microspheres

; Takahashi, Yoshihisa

Journal of Nuclear Materials, 182, p.195 - 202, 1991/00

 Times Cited Count:5 Percentile:53.89(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Behavior and removal of impurity sulphate in sol-gel process for ThO$$_{2}$$ and (Th,U)O$$_{2}$$ microsphere fabrication

; Takahashi, Yoshihisa

Journal of Nuclear Science and Technology, 26(10), p.939 - 947, 1989/10

no abstracts in English

Journal Articles

Preparation conditions and gelation behaviors of ThO$$_{2}$$-UO$$_{3}$$ sols for(Th, U)O$$_{2}$$ microsphere fabrication

; Takahashi, Yoshihisa

Journal of Nuclear Science and Technology, 25(11), p.848 - 856, 1988/11

no abstracts in English

Oral presentation

Observation of initial oxidation process on Si(110)-16$$times$$2 by real-time photoemission spectroscopy, 1

Togashi, Hideaki*; Kato, Atsushi*; Yamamoto, Yoshihisa*; Konno, Atsushi*; Narita, Yuzuru*; Suemitsu, Maki*; Teraoka, Yuden; Yoshigoe, Akitaka; Takahashi, Yuya*; Asaoka, Hidehito

no journal, , 

no abstracts in English

Oral presentation

Observation of initial oxidation process on Si(110)-16$$times$$2 by real-time photoemission spectroscopy, 2

Kato, Atsushi*; Togashi, Hideaki*; Yamamoto, Yoshihisa*; Konno, Atsushi*; Narita, Yuzuru*; Suemitsu, Maki*; Teraoka, Yuden; Yoshigoe, Akitaka; Takahashi, Yuya*; Asaoka, Hidehito

no journal, , 

no abstracts in English

31 (Records 1-20 displayed on this page)