Probabilistic risk assessment method development for high temperature gas-cooled reactors, 1; Project overviews

Sato, Hiroyuki; Nishida, Akemi; Ohashi, Hirofumi; Muramatsu, Ken*; Muta, Hitoshi*; Itoi, Tatsuya*; Takada, Tsuyoshi*; Hida, Takenori*; Tanabe, Masayuki*; Yamamoto, Tsuyoshi*; et al.

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 7 Pages, 2017/04

JAEA, in conjunction with Tokyo City University, The University of Tokyo and JGC Corporation, have started development of a PRA method considering the safety and design features of HTGR. The primary objective of the project is to develop a seismic PRA method which enables to provide a reasonably complete identification of accident scenario including a loss of safety function in passive system, structure and components. In addition, we aim to develop a basis for guidance to implement the PRA. This paper provides the overview of the activities including development of a system analysis method for multiple failures, a component failure data using the operation and maintenance experience in the HTTR, seismic fragility evaluation method, and mechanistic source term evaluation method considering failures in core graphite components and reactor building.

Full-coherent free electron laser seeded by 13th- and 15th-order harmonics of near-infrared femtosecond laser pulses

Sato, Takahiro*; Iwasaki, Atsushi*; Owada, Shigeki*; Yamanouchi, Kaoru*; Takahashi, Eiji*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; Togashi, Tadashi*; Fukami, Kenji*; et al.

Journal of Physics B; Atomic, Molecular and Optical Physics, 46(16), p.164006_1 - 164006_6, 2013/08

https://doi.org/10.1088/0953-4075/46/16/164006

By introducing 13th- (61.7 nm) and 15th-order harmonics (53.4 nm) of femtosecond laser pulses at 800 nm into an undulator of SCSS (SPring-8 Compact SASE Source) test accelerator at RIKEN, these harmonic pulses were amplified by a factor of more than 10 with a high contrast ratio through the interaction between accelerated electron bunches and the harmonic pulses. From numerical simulations of the amplification processes of high-order harmonic pulses in the undulator, optimum conditions of the electron bunch duration interacting with the high-order harmonic pulses were investigated for generating full-coherent and intense pulses in the extreme ultraviolet wavelength region.

Effect of heat treatment on TEM microstructures of Zirconium carbide coating layer in fuel particle for advanced high temperature gas cooled reactor

Aihara, Jun; Ueta, Shohei; Yasuda, Atsushi*; Takeuchi, Hitoshi*; Mozumi, Yasuhiro*; Sawa, Kazuhiro; Motohashi, Yoshinobu*

Materials Transactions, 50(11), p.2631 - 2636, 2009/11

https://doi.org/10.2320/matertrans.M2009185

The ZrC coating layer has been fabricated using the bromide process at JAEA. The coated particles with IPyC layers reported in a previous study were annealed at around 1800C for 1h, under which compact sintering will be done in a practical process, in order to study effects of the heat treatment (annealing) on their microstructure evolution. Then the microstructures of the ZrC layers in the cases (batches) of C/Zr = 1.11 and 1.35 were characterized by means of TEM and STEM. Certain changes in the shape and size of voids or free carbons region caused by the heat treatment were found in the cases of both batches. After the heat treatment, the voids or free carbons region have shown a clod like feature with diameters of 50 to 100 nm. The grain growth of ZrC was also observed in both cases: In the ZrC layer with C/Zr = 1.11, the fibrous carbons grew as of to stand from the PyC to ZrC layers on some places in the IPyC/ZrC boundary.

Current status of the control system for J-PARC accelerator complex

Yoshikawa, Hiroshi; Sakaki, Hironao; Sako, Hiroyuki; Takahashi, Hiroki; Shen, G.; Kato, Yuko; Ito, Yuichi; Ikeda, Hiroshi*; Ishiyama, Tatsuya*; Tsuchiya, Hitoshi*; et al.

Proceedings of International Conference on Accelerator and Large Experimental Physics Control Systems (ICALEPCS '07) (CD-ROM), p.62 - 64, 2007/10

J-PARC is a large scale facility of the proton accelerators for the multi-purpose of scientific researches in Japan. This facility consists of three accelerators and three experimental stations. Now, J-PARC is under construction, and LINAC is operated for one year, 3GeV synchrotron has just started the commissioning in this October the 1st. The completion of this facility will be next summer. The control system of accelerators established fundamental performance for the initial commissioning. The most important requirement to the control system of this facility is to minimize the activation of accelerator devices. In this paper, we show that the performances of each layer of this control system have been achieved in the initial stage.

Thermo- and pH-sensitive gel membranes based on poly-(acryloyl--proline methyl ester)--poly(acrylic acid) for selective permeation of metal ions

Hasegawa, Shin; Ohashi, Hitoshi; Maekawa, Yasunari; Katakai, Ryoichi*; Yoshida, Masaru

Radiation Physics and Chemistry, 72(5), p.595 - 600, 2005/04

https://doi.org/10.1016/j.radphyschem.2004.03.016

Thermo- and pH-responsive gel membranes were synthesized by -ray grafting of pH-responsive poly (acrylic acid) (AAc) onto thermo-responsive polymer gel of acryloyl--proline methyl ester (A-ProOMe). The gel membranes of poly (A-ProOMe) with 15 mol% graft chains of AAc exhibited both thermo- and pH-responses. Under the condition (pH 6.0, 30C) in which the thermo-sensitive unit shrinks and the pH-sensitive unit swells, the selective permeation of Li ion over Co and Ni ions can be achieved.

None

Masahiro, Motohashi,; Tadashi, Kyue,; Kiyonori, Ishii,; Ichinosawa, Hitoshi; Inanobe, Kazuhide*

Saikuru Kiko Giho, (22), 114- Pages, 2004/00

https://rdreview.jaea.go.jp/gihou/pdf2/n22-19.pdf

None

None

Masahiro, Motohashi,; Tadashi, Kyue,; Imamoto, Nobuo; Ichinosawa, Hitoshi; Inanobe, Kazuhide*

Saikuru Kiko Giho, (24), p.82 - 83, 2004/00

https://rdreview.jaea.go.jp/gihou/pdf2/n24-13.pdf

The general-condition report of LWTF is carried to "JNC Technical Review No.24 2004.9"

None

Motohashi, Masahiro; Kyue; Ishii; Ichinosawa, Hitoshi

Saikuru Kiko Giho, (19), 94- Pages, 2003/00

https://rdreview.jaea.go.jp/gihou/pdf2/n19-17.pdf

None

TEM/STEM observation of ZrC coating layer for advanced high temperature gas cooled reactor fuel, 3

Aihara, Jun; Ueta, Shohei; Yasuda, Atsushi; Takeuchi, Hitoshi; Sawa, Kazuhiro; Motohashi, Yoshinobu*

no journal, , 

We report in this study the microstructural change of the ZrC coating layers with annealing. We already reported the microstructures of as-fabricated ZrC coating layers last year. ZrC coated particles were annealed at about 1800 C for 1 hour to simulate the sintering process of the real HTGR fuel. With annealing, ZrC grains were slightly grown especially near the surface regions and kept their orientation. The free carbons and/or voids cohered at the grain boundaries. The cohered free carbons and/or voids were appeared to form the clods of the free carbon ribbons. In addition, IPyC/ZrC boundary structure changed. Fibrous carbon texture was found at IPyC/ZrC boundary even in the specimen of the batch of which that texture was not observed in the as-fabricated specimen.

Probabilistic risk assessment method development for high temperature gas-cooled reactors, 2; Development of source term evaluation method

Honda, Yuki; Sato, Hiroyuki; Ohashi, Hirofumi; Nishida, Akemi; Muta, Hitoshi*; Muramatsu, Ken*; Itoi, Tatsuya*; Tanabe, Masayuki*

no journal, , 

We have been conducting a source term evaluation method development for high temperature gas-cooled reactors considering structural failures in the major components. We will present the outline of evaluation method and results of transient analysis for unprotected depressurized loss-of-forced cooling accident which may be initiated by Beyond-Design-Basis Earthquake.

Seismic probabilistic risk assessment method development for high temperature gas-cooled reactors

Sato, Hiroyuki; Nishida, Akemi; Ohashi, Hirofumi; Muramatsu, Ken*; Muta, Hitoshi*; Matsuda, Kosuke*; Itoi, Tatsuya*; Takada, Tsuyoshi; Tanabe, Masayuki*; Yamamoto, Tsuyoshi*; et al.

no journal, ,