Refine your search:     
Report No.
 - 
Search Results: Records 1-10 displayed on this page of 10
  • 1

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Research and development on high burnup HTGR fuels in JAEA

Ueta, Shohei; Mizuta, Naoki; Sasaki, Koei; Sakaba, Nariaki; Ohashi, Hirofumi; Yan, X. L.

Mechanical Engineering Journal (Internet), 7(3), p.19-00571_1 - 19-00571_12, 2020/06

JAEA has been progressing to design HTGR fuels for not only small-type practical HTGRs but also VHTR proposed in GIF which can be utilized for various purposes with high-temperature heat at 750 to 950 $$^{circ}$$C. To increase economy of these HTGRs, JAEA has been upgrading the design method for the HTGR fuel, which can maintain their integrities at the burnup of three to four times higher than that of the conventional HTTR fuel. Design principles and specifications of various concepts of the high burnup HTGR fuels designed by JAEA are reported. As the latest results on post-irradiation examinations of the high burnup HTGR fuel progressing in a framework of international collaboration with Kazakhstan, irradiation shrinkage rate of the fuel compact as a function of fast neutron fluence was obtained at around 100 GWd/t. Furthermore, the future R&Ds needed for the high burnup HTGR fuel are described based on these experimental results.

Journal Articles

Research and development on high burnup HTGR fuels in JAEA

Ueta, Shohei; Mizuta, Naoki; Sasaki, Koei; Sakaba, Nariaki; Ohashi, Hirofumi; Yan, X. L.

Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 8 Pages, 2019/05

JAEA has been progressing to design HTGR fuels for not only small-type practical HTGRs but also VHTR proposed in GIF which can be utilized for various purposes with high-temperature heat at 750 to 950 $$^{circ}$$C. To increase economy of these HTGRs, JAEA has been upgrading the design method for the HTGR fuel, which can maintain their integrities at the burnup of three to four times higher than that of the conventional HTTR fuel. Design principles and specifications of various concepts of the high burnup HTGR fuels designed by JAEA are reported. As the latest results on post-irradiation examinations of the high burnup HTGR fuel progressing in a framework of international collaboration with Kazakhstan, irradiation shrinkage rate of the fuel compact as a function of fast neutron fluence was obtained at around 100 GWd/thm. Furthermore, the future R&Ds needed for the high burnup HTGR fuel are described based on these experimental results.

Journal Articles

Demonstration of under sodium viewer in Monju

Aizawa, Kosuke; Sasaki, Koei; Chikazawa, Yoshitaka; Fukuie, Masaru*; Jimbo, Noboru*

Nuclear Technology, 204(1), p.74 - 82, 2018/10

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

Development of inspection technique in opaque liquid metal coolant is one of the important issues to ensure the safety of Liquid Metal Fast Breeder Reactor (LMFBR). Performance tests of an Under Sodium Viewer (USV), which was developed to detect an obstacle in the reactor vessel (RV) of LMFBR Monju, have been carried out. The ultrasonic sensors and reflectors are located across the core inside of the Monju's RV. The USV can detect an obstacle existing in between the core top and the Upper Core Structure (UCS) bottom by identifying differences of echo signals. This report describes the USV performance tests. In the tests, the reference echo signals under various conditions were accumulated and the signal to noise ratio successfully exceeded the target value. Measured signals clearly differed from with and without an obstacle. These experimental results show the performance of the USV for detecting an obstacle in the specified place.

Journal Articles

Conceptual plant system design study of an experimental HTGR upgraded from HTTR

Ohashi, Hirofumi; Goto, Minoru; Ueta, Shohei; Sato, Hiroyuki; Fukaya, Yuji; Kasahara, Seiji; Sasaki, Koei; Mizuta, Naoki; Yan, X.; Aoki, Takeshi*

Proceedings of 9th International Topical Meeting on High Temperature Reactor Technology (HTR 2018) (USB Flash Drive), 6 Pages, 2018/10

Conceptual design study of an experimental HTGR is performed to upgrade the plant system from Japanese High Temperature engineering Test Reactor (HTTR) to a commercial HTGR. Safety systems of HTTR are upgraded to demonstrate the commercial HTGR concept, such as a passive reactor cavity cooling system, a confinement, etc. An intermediate heat exchanger (IHX) is replaced by a steam generator (SG) for a process heat supply to demonstrate the technology for a commercial use. This paper describes the conceptual design study results of the plant system of the experimental HTGR.

Journal Articles

Cs-Te corrosion depth dependence on distribution of chromium carbide precipitation in high chromium steel

Sasaki, Koei; Fujimura, Ryota*; Tanigaki, Takanori; Matsubara, Masanori*; Fukumoto, Kenichi*; Uno, Masayoshi*

Journal of Nuclear Science and Technology, 54(2), p.139 - 146, 2017/02

AA2016-0211.pdf:2.83MB

 Times Cited Count:3 Percentile:50.46(Nuclear Science & Technology)

In an attempt to investigate Cs-Te corrosion depth dependence on distribution of chromium carbide precipitation in high chromium steel, Cs-Te corrosion out-pile tests of two 9Cr steels with different distributions of chromium carbide were carried out at 975K for 100h and their corrosion depths were compared. The corrosion is obviously more advanced in a specimen which has grain boundary carbide than in the one that does not. A considerable reason of the result is that the carbide distributed at grain boundaries promoted the corrosion reaction and the corrosion extended along the grain boundary. This is the first case in which the Cs-Te corrosion depth dependence on distribution of chromium carbide precipitation in Fe-Cr steel is clarified experimentally.

Journal Articles

Performance test of under sodium viewer in Monju

Aizawa, Kosuke; Togashi, Yoshinori; Sasaki, Koei; Chikazawa, Yoshitaka; Fukuie, Masaru*; Jimbo, Noboru*

Proceedings of 2015 International Congress on Advances in Nuclear Power Plants (ICAPP 2015) (CD-ROM), p.808 - 816, 2015/05

Inspection technique in opaque liquid metal coolant is one of the important issues for the safety warranty of Liquid Metal Fast Breeder Reactor (LMFBR) core. A performance test of Under Sodium Viewer (USV) which was developed to detect obstacles in reactor vessel of LMFBR Monju was carried out. The ultrasonic sensors and reflectors are located across the core inside the Monju reactor vessel. The USV detects the obstacle between the core top and the bottom of Upper Core Structure (UCS) by differences of echo signals. This reports showed the USV performance test in Monju before power operation. In the test, the basic echo signals in various conditions were accumulated and signal to noise ratio met with the design value. Measured signals with and without obstacles showed difference clearly. Those experimental results showed that basic performance of the USV to detect an obstacle between the core and UCS.

Oral presentation

The Chemical stability of Al$$_{2}$$O$$_{3}$$ FCCI barrier on oxide fuel pin of sodium fast reactor

Sasaki, Koei

no journal, , 

(Introduction) Candidate materials of fuel cladding for Gen-IV sodium fast reactor require to develop resistance to fuel cladding chemical interaction (FCCI) for future enhancement of burn-ups ($$sim$$20at.%). In this work, we propose a preventive technique of FCCI in oxide fuel pins by Al$$_{2}$$O$$_{3}$$ film coating on fuel cladding inner surface as a FCCI barrier. It has been reported that fission product (FP) corrosions including Cesium, Cesium-Tellurium and Iodine corrosion, play an important role in FCCI behavior based on in-pile and out-pile test results. The Al$$_{2}$$O$$_{3}$$ film coating on the cladding material surface is able to work as FCCI barrier to protect the corrosive FP elements due to the high chemical stability. (Experiment) In this work, a thin Al$$_{2}$$O$$_{3}$$ film was experimentally formed on a Fe-12Cr-5Al ternary alloy during heat treatment in controlled atmosphere $$Delta$$G$$_{rm O2}$$ = -870$$sim$$-550 kJ/mol at 1173 K for 30 hours. A transmission electron microscope (TEM) image and energy dispersive X-ray (EDX) mapping images of the formed Al$$_{2}$$O$$_{3}$$ film are shown in Fig.1. Examinations of Cesium, Cesium-Tellurium and Iodine corrosion were performed on the Al$$_{2}$$O$$_{3}$$ film in order to evaluate its chemical stability. *Cesium/Cesium-Tellurium corrosion test. The Al$$_{2}$$O$$_{3}$$ coated specimen was immersed in Cesium or Cesium-Tellurium mixture in analumina crucible and was heated at 923 K for 10 or 100 hours in controlled atmosphere $$Delta$$G$$_{rm O2}$$ = -420 kJ/mol. *Iodine corrosion test Iodine corrosion test was briefly carried out at 923 K for 10 or 100 hours in an enclosed quartstube containing the specimen and pure iodine chips. (Result) Scanning electron microscope observations and EDX analyses of the specimens after the corrosion tests showed that the corrosions of each corrosive FP element were prevented by the Al$$_{2}$$O$$_{3}$$ coating on the specimens.

Oral presentation

R&D results on ZrC-TRISO CFP in JAEA

Sasaki, Koei

no journal, , 

The information exchange meeting with KAERI is held once a year for the purpose of information exchange based on public information and this meeting was held from 5/20 to 5/21 at National Jeju University in Korea. Sasaki reported research and development results of ZrC coated fuel in JAEA.

Oral presentation

Design of high burnup fuel for HTGR

Sasaki, Koei

no journal, , 

"Design of high burnup fuel for HTGR" was instructed for "3rd Seminar on Development of HTGR Technology for Cogeneration and Heat Applications" as a part of "Implementing Agreement between the Japan Atomic Energy Agency and National Centre for Nuclear Research in the Republic of Poland for cooperation in research and development in the field of high temperature gas-cooled reactor technologies".

Oral presentation

Development of a Cs getter contained coated fuel particle layer for high temperature gas cooled reactor

Sasaki, Koei

no journal, , 

We are developing a fuel coating material with a Cs capture function in anticipation of reducing the exposure dose of HTGR plants, improving safety in the event of a primary reactor accident, making the plant more compact and reducing construction costs due to the reduction of shielding wall thickness. Bi and Sb were selected as Cs getter materials. Their simulated Cs trap compounds were formed in the carbon structure and high temperature stability at 1500$$^{circ}$$C was evaluated. Although Bi was precipitated in carbon, the formation of Cs compounds could not be seen. Sb formed a Cs compound (Cs$$_{3}$$Sb, etc.) in carbon structure and showed stability at 1500$$^{circ}$$C. Therefore, it was found that Sb has a Cs trap function.

10 (Records 1-10 displayed on this page)
  • 1