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Journal Articles

Thermophysical properties of austenitic stainless steel containing boron carbide in a solid state

Takai, Toshihide; Furukawa, Tomohiro; Yamano, Hidemasa

Mechanical Engineering Journal (Internet), 8(4), p.20-00540_1 - 20-00540_11, 2021/08

In a core disruptive accident scenario, boron carbide, which is used as a control rod material, may melt below the melting temperature of stainless steel owing to the eutectic reaction with them. The eutectic mixture produced is assumed to extensively relocate in the degraded core, and this behavior plays an important role in significantly reducing the neutronic reactivity. However, these behaviors have never been simulated in previous severe accident analysis. To contribute to the improvement of the core disruptive accident analysis code, the thermophysical properties of the eutectic mixture in the solid state were measured, and regression equations that show the temperature (and boron carbide concentration) dependence are created.

Journal Articles

Advanced concepts in TRISO fuel

Minato, Kazuo; Ogawa, Toru

Comprehensive Nuclear Materials, 2nd Edition, Vol.5, p.334 - 360, 2020/08

TRISO coated particle fuel has been developed for the high temperature gas-cooled reactors, which consists of microspherical fuel kernel and coating layers of pyrolytic carbon and silicon carbide. To improve the high temperature stability, the resistance to the chemical attack by fission products and the retention of fission products of the TRISO coated particle fuels, several types of advanced fuels were proposed and tested. Coated particle fuels for fast reactors were also proposed and tested. In this paper, fuel designs, fabrications, characterization techniques and fuel performance of these advanced coated particle fuels are systematically described. This is the updated version of the paper having the same title in Comprehensive Nuclear Materials published in 2012.

Journal Articles

Journal Articles

Study on plutonium burner high temperature gas-cooled reactor in Japan; Introduction scenario, reactor safety and fabrication tests of the 3S-TRISO fuel

Ueta, Shohei; Mizuta, Naoki; Fukaya, Yuji; Goto, Minoru; Tachibana, Yukio; Honda, Masaki*; Saiki, Yohei*; Takahashi, Masashi*; Ohira, Koichi*; Nakano, Masaaki*; et al.

Nuclear Engineering and Design, 357, p.110419_1 - 110419_10, 2020/02

 Times Cited Count:1 Percentile:39.17(Nuclear Science & Technology)

The concept of a plutonium (Pu) burner HTGR is proposed to incarnate highly-effective Pu utilization by its inherent safety features. The security and safety fuel (3S-TRISO fuel) employs the coated fuel particle with a fuel kernel made of plutonium dioxide (PuO$$_{2}$$) and yttria stabilized zirconia (YSZ) as an inert matrix. This paper presents feasibility study of Pu burner HTGR and R&D on the 3S-TRISO fuel.

Journal Articles

Thermophysical properties of stainless steel containing 5 mass%B$$_{4}$$C in the solid phase

Takai, Toshihide; Furukawa, Tomohiro; Yamano, Hidemasa

Nuclear Technology, 205(9), p.1164 - 1174, 2019/09

 Times Cited Count:3 Percentile:57.07(Nuclear Science & Technology)

Journal Articles

Study on eutectic melting behavior of control rod materials in core disruptive accidents of sodium-cooled fast reactor, 2; Effect of B$$_{4}$$C addition on thermophysical properties of austenitic stainless steel in a solid state

Takai, Toshihide; Furukawa, Tomohiro; Yamano, Hidemasa

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.847 - 852, 2019/09

Journal Articles

Oxidation of silicon carbide in steam studied by laser heating

Pham, V. H.; Nagae, Yuji; Kurata, Masaki; Furumoto, Kenichiro*; Sato, Hisaki*; Ishibashi, Ryo*; Yamashita, Shinichiro

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.670 - 674, 2019/09

Journal Articles

Development of security and safety fuel for Pu-burner HTGR; Test and characterization for ZrC coating

Ueta, Shohei; Aihara, Jun; Goto, Minoru; Tachibana, Yukio; Okamoto, Koji*

Mechanical Engineering Journal (Internet), 5(5), p.18-00084_1 - 18-00084_9, 2018/10

To develop the security and safety fuel (3S-TRISO fuel) for Pu-burner high temperature gas-cooled reactor (HTGR), R&D on zirconium carbide (ZrC) directly coated on yttria stabilized zirconia (YSZ) has been started in the Japanese fiscal year 2015. As results of the direct coating test of ZrC on the dummy YSZ particle, ZrC layers with 18 - 21 microns of thicknesses have been obtained with 0.1 kg of particle loading weight. No deterioration of YSZ exposed by source gases of ZrC bromide process was observed by Scanning Transmission Electron Microscope (STEM).

Journal Articles

Study on Pu-burner high temperature gas-cooled reactor in Japan; Test and characterization for ZrC coating

Ueta, Shohei; Aihara, Jun; Mizuta, Naoki; Goto, Minoru; Fukaya, Yuji; Tachibana, Yukio; Okamoto, Koji*

Proceedings of 9th International Topical Meeting on High Temperature Reactor Technology (HTR 2018) (USB Flash Drive), 7 Pages, 2018/10

The security and safety fuel (3S-TRISO fuel) employs the coated fuel particle with a fuel kernel made of plutonium dioxide (PuO$$_{2}$$) and yttria stabilized zirconia (YSZ) as an inert matrix. Especially, a zirconium carbide (ZrC) coating is one of key technologies of the 3S-TRISO, which performs as an oxygen getter to reduce the fuel failure due to internal pressure during the irradiation. R&Ds on ZrC coating directly on the dummy CeO$$_{2}$$-YSZ kernel have been carried in the Japanese fiscal year 2017. As results of ZrC coating tests by the bromide chemical vapor deposition process, stoichiometric ZrC coatings with 3 - 18 microns of thicknesses were obtained with 0.1 kg of particle loading weight.

Journal Articles

Thermophysical properties of stainless steel containing 5mass%-B$$_{4}$$C in the solid phase

Takai, Toshihide; Furukawa, Tomohiro; Yamano, Hidemasa

Proceedings of 2018 International Congress on Advances in Nuclear Power Plants (ICAPP 2018) (CD-ROM), p.1007 - 1013, 2018/04

Journal Articles

Technical basis of accident tolerant fuel updated under a Japanese R&D project

Yamashita, Shinichiro; Nagase, Fumihisa; Kurata, Masaki; Nozawa, Takashi; Watanabe, Seiichi*; Kirimura, Kazuki*; Kakiuchi, Kazuo*; Kondo, Takao*; Sakamoto, Kan*; Kusagaya, Kazuyuki*; et al.

Proceedings of 2017 Water Reactor Fuel Performance Meeting (WRFPM 2017) (USB Flash Drive), 10 Pages, 2017/09

In Japan, the research and development (R&D) project on accident tolerant fuel and other components (ATFs) of light water reactors (LWRs) has been initiated in 2015 for establishing technical basis of ATFs. The Japan Atomic Energy Agency (JAEA) has coordinated and carried out this ATF R&D project in cooperation with power plant providers, fuel venders and universities for making the best use of the experiences, knowledges in commercial uses of zirconium-base alloys (Zircaloy) in LWRs. ATF candidate materials under consideration in the project are FeCrAl steel strengthened by dispersion of fine oxide particles(FeCrAl-ODS) and silicon carbide (SiC) composite, and are expecting to endure severe accident conditions in the reactor core for a longer period of time than the Zircaloy while maintaining or improving fuel performance during normal operations. In this paper, the progresses of the R&D project are reported.

Journal Articles

Examination of $$^{131}$$I and $$^{137}$$Cs releases during late phase of Fukushima Daiichi NPP accident by using $$^{131}$$I/$$^{137}$$Cs ratio of source terms evaluated reversely by WSPEEDI code with environmental monitoring data

Hidaka, Akihide; Yokoyama, Hiroya

Journal of Nuclear Science and Technology, 54(8), p.819 - 829, 2017/08

AA2016-0500.pdf:0.44MB

 Times Cited Count:9 Percentile:75.2(Nuclear Science & Technology)

To clarify what happened during the Fukushima accident, the phenomena within RPV and the discussion of ties with the environmental monitoring are very important. However, the previous study has not necessarily advanced until the present that passed almost six years from the accident. The present study investigated $$^{131}$$I and $$^{137}$$Cs release behaviors during the late phase of the accident based on $$^{131}$$I/$$^{137}$$Cs ratio of the source terms that were recently evaluated backward by WSPEEDI code based on environmental monitoring data. The $$^{131}$$I release from the contaminated water in the basement of 1F2 and 1F3 reactor buildings was evaluated to be about 10% of $$^{131}$$I source term. The increase in $$^{137}$$Cs release from March 21 to 23 and from March 30 to 31 could be explained by the release of CsBO$$_{2}$$ which is formed as a result of chemical reactions of Cs with B$$_{4}$$C due to re-ascension of the core temperature caused by slight shortage of the core cooling water.

Journal Articles

Development of security and safety fuel for Pu-burner HTGR, 5; Test and characterization for ZrC coating

Ueta, Shohei; Aihara, Jun; Goto, Minoru; Tachibana, Yukio; Okamoto, Koji*

Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 4 Pages, 2017/07

To develop the security and safety fuel (3S-TRISO fuel) for Pu-burner high temperature gas-cooled reactor (HTGR), R&D on zirconium carbide (ZrC) directly coated on yttria stabilized zirconia (YSZ) has been started in the Japanese fiscal year 2015. As results of the direct coating test of ZrC on the dummy YSZ particle, ZrC layers with 18 - 21 microns of thicknesses have been obtained with 0.1 kg of particle loading weight. No deterioration of YSZ exposed by source gases of ZrC bromide process was observed by Scanning Transmission Electron Microscope (STEM).

Journal Articles

Basic visualization experiments on eutectic reaction between boron carbide and stainless steel under sodium-cooled fast reactor conditions

Yamano, Hidemasa; Suzuki, Toru; Kamiyama, Kenji; Kudo, Isamu*

Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Next Generation Nuclear Systems for Sustainable Development (FR-17) (USB Flash Drive), 11 Pages, 2017/06

This paper describes basic visualization experiments on eutectic reaction and relocation of boron carbide (B$$_{4}$$C) and stainless steel (SS) under a high temperature condition exceeding 1500$$^{circ}$$C as well as the importance of such behaviors in molten core during a core disruptive accident in a Generation-IV sodium-cooled fast reactor (750 MWe class) designed in Japan. At first, a reactivity history was calculated using an exact perturbation calculation tool taking into account expected behaviors. This calculation indicated the importance of a relocation behavior of the B$$_{4}$$C-SS eutectic because its behavior has a large uncertainty in the reactivity history. To clarify this behavior, basic experiments were carried out by visualizing the reaction of a B$$_{4}$$C pellet contacted with molten SS in a high temperature-heating furnace. The experiments have shown the eutectic reaction visualization as well as freezing and relocation of the B$$_{4}$$C-SS eutectic in upper part of the solidified test piece due to the density separation.

JAEA Reports

Boron release kinetics from mixed melts of boron carbide, stainless steel and Zircaloy; A Literature review on the behavior of control rod materials under severe accidents

Di Lemma, F. G.; Miwa, Shuhei; Osaka, Masahiko

JAEA-Review 2016-007, 27 Pages, 2016/03

JAEA-Review-2016-007.pdf:1.88MB

During a nuclear power plant Severe Accident, complex boron melts can be formed, due to interaction of the control rods with the cladding materials. These can affect ultimately the source term assessment. This review will describe the results of previous studies on boron carbide/stainless steel/Zircaloy (B$$_{4}$$C/SS/Zry) melts, which will finally provide guidance for the needs of future experiments. This review showed that models for the behavior of complex B$$_{4}$$C/SS/Zry melts are limited, and unsuccessful in simulating core degradation, thus the improvement of the database for B$$_{4}$$C/SS/Zry melts is needed. Our experimental plan aims in providing thermodynamics and kinetics models for such melts, with the final aim of improving boron modelling in SA codes analysis and of understanding its effect on fission products behavior.

Journal Articles

Activation and control of visible single defects in 4H-, 6H-, and 3C-SiC by oxidation

Lohrmann, A.*; Castelletto, S.*; Klein, J. R.*; Oshima, Takeshi; Bosi, M.*; Negri, M.*; Lau, D. W. M.*; Gibson, B. C.*; Prawer, S.*; McCallum, J. C.*; et al.

Applied Physics Letters, 108(2), p.021107_1 - 021107_4, 2016/01

 Times Cited Count:26 Percentile:81.53(Physics, Applied)

Journal Articles

Swelling of radiation-cured polymer precursor powder for silicon carbide by pyrolysis

Takeyama, Akinori; Idesaki, Akira; Sugimoto, Masaki; Yoshikawa, Masahito

Journal of Asian Ceramic Societies (Internet), 3(4), p.402 - 406, 2015/12

Journal Articles

Defect engineering in silicon carbide; Single photon sources, quantum sensors and RF emitters

Kraus, H.; Simin, D.*; Fuchs, F.*; Onoda, Shinobu; Makino, Takahiro; Dyakonov, V.*; Oshima, Takeshi

Proceedings of 11th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-11) (Internet), p.176 - 179, 2015/11

Journal Articles

A Development of super radiation-hardened power electronics using silicon carbide semiconductors; Toward MGy-class radiation resistivity

Hijikata, Yasuto*; Mitomo, Satoshi*; Matsuda, Takuma*; Murata, Koichi*; Yokoseki, Takashi*; Makino, Takahiro; Takeyama, Akinori; Onoda, Shinobu; Okubo, Shuichi*; Tanaka, Yuki*; et al.

Proceedings of 11th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-11) (Internet), p.130 - 133, 2015/11

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