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Journal Articles

First freezing experiments with a molten mixture of boron carbide and stainless steel in core disruptive accidents of sodium-cooled fast reactors

Emura, Yuki; Matsuba, Kenichi; Kikuchi, Shin; Yamano, Hidemasa

Proceedings of 13th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS13) (Internet), 8 Pages, 2024/11

Journal Articles

Thinning behavior of solid boron carbide immersed in molten stainless steel for core disruptive accident of sodium-cooled fast reactor

Emura, Yuki; Takai, Toshihide; Kikuchi, Shin; Kamiyama, Kenji; Yamano, Hidemasa; Yokoyama, Hiroki*; Sakamoto, Kan*

Journal of Nuclear Science and Technology, 61(7), p.911 - 920, 2024/07

 Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)

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

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:11 Percentile:71.09(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

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

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:13 Percentile:73.88(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

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

Fast spectrum control rod materials

Nagata, Takako; Maeda, Koji

Comprehensive Nuclear Materials, Vol.3, p.509 - 534, 2012/00

This article is a review of fast reactor control rod materials and is part of the Elsevier Comprehensive Nuclear Materials Series. Control rods have three primary functions; reactivity compensation during the operating cycle, start-and-stop control for normal operation, and rapid shutdown during abnormal conditions. As an absorber material, boron carbide (B$$_{4}$$C) is mainly used in fast reactor systems, such as the Japanese experimental reactor JOYO. The current core configuration of JOYO is Mark-3 (MK-3). The control rods are inserted automatically when abnormal conditions occur. In both the MK-2 and MK-3 cores, all control rods have the same structure and functions. Every control rod assembly has seven control rod elements, and B$$_{4}$$C pellets are used as absorbers. The boron in B$$_{4}$$C includes $$^{10}$$B and $$^{11}$$B. Control rods function as safety (shutdown) rods, regulating rods, rapid shutdown rods, additional shutdown rods, absorber pins, worth of controlled rods, vertical travel of control rods, rod-drop time, and features of the drive mechanism.

Journal Articles

Diagnostics of pulsed plasma in laser ablation of boron compounds

Oba, Hironori; Saeki, Morihisa; Yokoyama, Atsushi

Proceedings of Plasma Science Symposium 2005/22nd Symposium on Plasma Processing (PSS-2005/SPP-22), p.331 - 332, 2005/01

A plasma produced by a XeCl laser ablation of boron compound was investigated using ion probes and a quadrupole mass spectrometer. Although the ablated neutral boron atoms had a natural abundance ratio, the isotope ratio of singly ionized boron atoms having a greatly different from the natural abundance ratio was observed. The observed isotope ratio of boron ions was different from the natural abundance.

Journal Articles

Sputtering experiments on B$$_{4}$$C doped CFC under high particle flux with low energy

Nakamura, Kazuyuki; Dairaku, Masayuki; Akiba, Masato; Okumura, Yoshikazu

Journal of Nuclear Materials, 241-243, p.1142 - 1146, 1997/00

 Times Cited Count:9 Percentile:59.37(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

New composite composed of boron carbide and carbon fiber with high thermal conductivity for first wall

; Saido, Masahiro; Nakamura, Kazuyuki; Akiba, Masato; ; Goto, Yoshitaka*; ; ; Yamaki, Takahiro*; ; et al.

Journal of Nuclear Materials, 233-237(PT.A), p.781 - 786, 1996/00

 Times Cited Count:13 Percentile:71.95(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Delayed neutron emission measurements from fast fission of U-235 and NP-237

W.S.Charlton*; T.A.Parish*; S.Raman*; Shinohara, Nobuo; Ando, Masaki

PHYSOR 96: Int. Conf. on the Physics of Reactors, 3, p.F11 - F20, 1996/00

no abstracts in English

Journal Articles

Thermodynamic analysis of behavior of HTGR fuel and fission products under accidental air or water ingress conditions

Minato, Kazuo; Fukuda, Kosaku

IAEA-TECDOC-784, 0, p.86 - 91, 1995/01

no abstracts in English

Journal Articles

Optimization method of rod-type burnable poisons for nuclear designs of HTGRs

Yamashita, Kiyonobu

Journal of Nuclear Science and Technology, 31(9), p.979 - 985, 1994/09

 Times Cited Count:6 Percentile:51.78(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Compatibility of Heat Resistant Alloys With Boron Carbide,2

; ; ; ;

JAERI-M 82-196, 29 Pages, 1982/12

JAERI-M-82-196.pdf:2.41MB

no abstracts in English

JAEA Reports

Compatibility of Heat Resistant Alloys with Boron Carbide

;

JAERI-M 9185, 20 Pages, 1980/11

JAERI-M-9185.pdf:3.77MB

no abstracts in English

23 (Records 1-20 displayed on this page)