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Journal Articles

Effect of B$$_{4}$$C addition on the solidus and liquidus temperatures, density and surface tension of type 316 austenitic stainless steel in the liquid state

Fukuyama, Hiroyuki*; Higashi, Hideo*; Yamano, Hidemasa

Journal of Nuclear Materials, 554, p.153100_1 - 153100_11, 2021/10

 Times Cited Count:0 Percentile:0.01(Materials Science, Multidisciplinary)

The effects of B$$_{4}$$C addition on the solidus and liquidus temperatures of type 316 austenitic stainless steel (SS), and on the density and surface tension of molten SS, were experimentally studied. The solidus temperature of SS-x mass% B$$_{4}$$C (from 0 to 10) monotonically decreased from 1666 to 1307 K with B$$_{4}$$C addition. The liquidus temperature had a minimum at around 2.5 mass% B$$_{4}$$C, and increased with further B$$_{4}$$C addition up to 10 mass%. The density and surface tension of molten SS-x mass %B$$_{4}$$C were successfully measured over a wide temperature range (including an undercooling region) via an electromagnetic-levitation technique. The density of each sample decreased linearly with temperature. The density also monotonically decreased with B$$_{4}$$C content. Although the addition of B$$_{4}$$C had no clear effect on the surface tension of SS-x mass %B$$_{4}$$C, sulfur dissolved in SS316L caused a significant decrease in the surface tension.

Journal Articles

Study on eutectic melting behavior of control rod materials in core disruptive accidents of sodium-cooled fast reactors, 1; Project overview and progress until 2019

Yamano, Hidemasa; Takai, Toshihide; Furukawa, Tomohiro; Kikuchi, Shin; Emura, Yuki; Kamiyama, Kenji; Fukuyama, Hiroyuki*; Higashi, Hideo*; Nishi, Tsuyoshi*; Ota, Hiromichi*; et al.

Proceedings of 28th International Conference on Nuclear Engineering; Nuclear Energy the Future Zero Carbon Power (ICONE 28) (Internet), 11 Pages, 2021/08

One of the key issues in a core disruptive accident (CDA) evaluation in sodium-cooled fast reactors is eutectic reactions between boron carbide (B$$_{4}$$C) and stainless steel (SS) as well as its relocation. Such behaviors have never been simulated in CDA numerical analyses in the past, therefore it is necessary to develop a physical model and incorporate the model into the CDA analysis code. This study focuses on B$$_{4}$$C-SS eutectic melting experiments, thermophysical property measurement of the eutectic melt, and physical model development for the eutectic melting reaction. The eutectic experiments involve the visualization experiments, eutectic reaction rate experiments and material analyses. The thermophysical properties are measured in a range from solid to liquid state. The physical model is developed for a CDA computer code based on the measured data of the eutectic reaction rate and the physical properties. This paper describes the project overview and progress of experimental and analytical studies conducted until 2019. Specific results in this paper are the validation of physical model describing B$$_{4}$$C-SS eutectic reaction in the CDA analysis code, SIMMER-III, through the numerical analysis of the B$$_{4}$$C-SS eutectic melting experiments in which a B$$_{4}$$C block was placed in a SS pool.

Journal Articles

Behavior of light elements in iron-silicate-water-sulfur system during early Earth's evolution

Iizuka, Riko*; Goto, Hirotada*; Shito, Chikara*; Fukuyama, Ko*; Mori, Yuichiro*; Hattori, Takanori; Sano, Asami; Funakoshi, Kenichi*; Kagi, Hiroyuki*

Scientific Reports (Internet), 11(1), p.12632_1 - 12632_10, 2021/06

 Times Cited Count:0 Percentile:0.01(Multidisciplinary Sciences)

The Earth's core consist of Fe-Ni alloy with some light elements (H, C, O, Si, S etc.). Hydrogen (H) is the most abundant element in the universe and one of the promising candidates. In this study, we have investigated the effects of sulfur(S) on hydrogenation of iron-hydrous silicate system containing saturated water in the ideal composition of the primitive Earth. We observed a series of phase transitions of Fe, dehydration of the hydrous mineral, and formation of olivine and enstatite with increasing temperature. The FeS formed as the coexisting phase of Fe under high-pressure and temperature condition, but its unit cell volume did not increase, suggesting that FeS is hardly hydrogenated. Recovered samples exhibited that H and S can be incorporated into solid Fe, which lowers the melting temperature as Fe(H$$_{x}$$)-FeS system. No detection of other light elements (C, O, Si) in solid Fe suggests that they dissolve into molten iron hydride and/or FeS in the later process of Earth's core-mantle differentiation.

Journal Articles

Study on eutectic melting behavior of control rod materials in core disruptive accidents of sodium-cooled fast reactors, 1; Project overview and progress until 2018

Yamano, Hidemasa; Takai, Toshihide; Furukawa, Tomohiro; Kikuchi, Shin; Emura, Yuki; Kamiyama, Kenji; Fukuyama, Hiroyuki*; Higashi, Hideo*; Nishi, Tsuyoshi*; Ota, Hiromichi*; et al.

Proceedings of 2020 International Conference on Nuclear Engineering (ICONE 2020) (Internet), 10 Pages, 2020/08

One of the key issues in a core disruptive accident (CDA) evaluation in sodium-cooled fast reactors is eutectic reactions between boron carbide (B$$_{4}$$C) and stainless steel (SS) as well as its relocation. Such behaviors have never been simulated in CDA numerical analyses in the past, therefore it is necessary to develop a physical model and incorporate the model into the CDA analysis code. This study focuses on B$$_{4}$$C-SS eutectic melting experiments, thermophysical property measurement of the eutectic melt, and physical model development for the eutectic melting reaction. The eutectic experiments involve the visualization experiments, eutectic reaction rate experiments and material analyses. The thermophysical properties are measured in a range from solid to liquid state. The physical model is developed for a severe accident computer code based on the measured data of the eutectic reaction rate and the physical properties. This paper describes the project overview and progress of experimental and analytical studies conducted until 2018. Specific results in this paper are boron concentration distributions of solidified B$$_{4}$$C-SS eutectic sample in the eutectic melting experiments, which would be used for the validation of the eutectic physical model implemented into the computer code.

Journal Articles

Thermophysical properties of molten stainless steel containing 5mass%B$$_{4}$$C

Fukuyama, Hiroyuki*; Higashi, Hideo*; Yamano, Hidemasa

Nuclear Technology, 205(9), p.1154 - 1163, 2019/09

 Times Cited Count:13 Percentile:96.03(Nuclear Science & Technology)

An electromagnetic-levitation technique performed in a static magnetic field was used to measure the density, surface tension, normal spectral emissivity, heat capacity, and thermal conductivity of molten 316L stainless steel (SS316L) and SS316L that contained 5mass%B$$_{4}$$C. The addition of 5mass%B$$_{4}$$C to SS316L yielded reductions of 111 K, 6%, 19%, and 6% in the liquidus temperature, density, normal spectral emissivity, and thermal conductivity at the liquidus temperature of SS316L, respectively. The heat capacity increased by 5% with this addition. Although the 5mass%B$$_{4}$$C addition had no clear effect on the surface tension, sulfur dissolved in the SS316L resulted in a significant decrease in the surface tension.

Journal Articles

Study on eutectic melting behavior of control rod materials in core disruptive accidents of sodium-cooled fast reactors, 1; Project overview

Yamano, Hidemasa; Takai, Toshihide; Furukawa, Tomohiro; Kikuchi, Shin; Emura, Yuki; Kamiyama, Kenji; Fukuyama, Hiroyuki*; Higashi, Hideo*; Nishi, Tsuyoshi*; Ota, Hiromichi*; et al.

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.418 - 427, 2019/09

Eutectic reactions between boron carbide (B$$_{4}$$C) and stainless steel (SS) as well as its relocation are one of the key issues in a core disruptive accident (CDA) evaluation in sodium-cooled fast reactors. Since such behaviors have never been simulated in CDA numerical analyses, it is necessary to develop a physical model and incorporate the model into the CDA analysis code. This study is focusing on B$$_{4}$$C-SS eutectic melting experiments, thermophysical property measurement of the eutectic melt, and physical model development for the eutectic melting reaction. The eutectic experiments involve the visualization experiments, eutectic reaction rate experiments and material analyses. The thermophysical properties are measured in the range from solid to liquid state. The physical model is developed for a severe accident computer code based on the measured data of the eutectic reaction rate and the physical properties. This paper describes the project overview and progress of experimental and analytical studies by 2017. Specific results in this paper is boron concentration distributions of solidified B$$_{4}$$C-SS eutectic sample in the eutectic melting experiments, which would be used for the validation of the eutectic physical model implemented into the computer code.

Journal Articles

Study on eutectic melting behavior of control rod materials in core disruptive accidents of sodium-cooled fast reactors, 3; Effect of B$$_{4}$$C addition on thermophysical properties of austenitic stainless steel in a liquid state

Fukuyama, Hiroyuki*; Higashi, Hideo*; Yamano, Hidemasa

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.853 - 857, 2019/09

Thermophysical properties of molten mixture of 316L stainless steel (SS316L) and control-rod material (B$$_{4}$$C) are necessary for the development of computer simulation codes that describe core degradation mechanisms during severe accidents in nuclear power plants involving sodium-cooled fast reactors. The effect of B$$_{4}$$C addition to SS316L on the solidus and liquidus temperatures were first measured by differential scanning calorimetry. An electromagnetic levitation technique performed in a static magnetic field was used to measure the density, surface tension, normal spectral emissivity, specific heat capacity, and thermal conductivity of molten SS316L and SS316L containing B$$_{4}$$C. The effects of B$$_{4}$$C addition to SS316L on the thermophysical properties were studied up to 10 mass%.

Journal Articles

Thermophysical properties of molten stainless steel containing 5mass%-B$$_{4}$$C

Fukuyama, Hiroyuki*; Higashi, Hideo*; Yamano, Hidemasa

Proceedings of 2018 International Congress on Advances in Nuclear Power Plants (ICAPP 2018) (CD-ROM), p.1014 - 1019, 2018/04

In this study, densities, surface tensions, normal spectral emissivities, heat capacities and thermal conductivities of molten SUS316L and SUS316L containing 5mass%-B$$_{4}$$C were measured by the electromagnetic levitation technique in a static magnetic field.

Journal Articles

High pressure and temperature synthesis of Bi-based perovskite Bi$$_{0.5}$$Na$$_{0.5-x}$$Li$$_x$$)TiO$$_3$$

Fukunaga, Masanori; Yoneda, Yasuhiro; Fukuyama, Ryota*; Saito, Hiroyuki; Ikeda, Naoshi*; Katayama, Yoshinori

Transactions of the Materials Research Society of Japan, 35(1), p.111 - 114, 2010/03

High-pressure synthesis of bismuth based perovskite (Bi$$_{0.5}$$Na$$_{0.5-x}$$Li$$_x$$)TiO$$_3$$ (BNLT) ($$x$$=0.1, 0.15, 0.2, 0.25, 0.4, 0.5) was demonstrated. Single phase BNLTs with perovskite structure were successfully synthesized for $$x$$$$leq$$0.1 by the solid state reaction method. The solid phase reaction occurred in the pressure range of 6-10 GPa, and in the temperature range of 800-1200 $$^{circ}$$C. Two thermal anomalies were observed in single phase perovskite BNLT ($$x$$=0.1) as well as (Bi,Na)TiO$$_3$$. The cusp like anomaly at 210 $$^{circ}$$C was assigned to a rhombohedral-tetragonal structural phase transition. The finished products of $$x$$$$geq$$0.2 included three kinds of impurities, which were affected by the selection of starting materials.

Oral presentation

Noncontact density measurements of liquid SUS316, Fe and Ni

Watanabe, Makoto*; Higashi, Hideo*; Sasaki, Minako*; Adachi, Masayoshi*; Otsuka, Makoto*; Fukuyama, Hiroyuki*; Nishi, Tsuyoshi; Yamano, Hidemasa

no journal, , 

This reports results of density measurement of molten iron and nickel that are main components of stainless steel 316 of cladding of control rod as part of thermophysical properties studies of molten control rod material in BWR.

Oral presentation

Density measurements of molten SUS316, Fe and Ni using an electromagnetic levitation technique under a static magnetic field

Watanabe, Makoto*; Higashi, Hideo*; Sasaki, Minako*; Adachi, Masayoshi*; Otsuka, Makoto*; Fukuyama, Hiroyuki*; Nishi, Tsuyoshi; Yamano, Hidemasa

no journal, , 

In this study, as a first step, density of the stainless steel 316 (SUS316), pure Fe and Ni were measured. For all samples, the densities are expressed with a linear function of temperature.

Oral presentation

Surface tension measurements of liquid SUS316

Higashi, Hideo*; Fukuyama, Hiroyuki*; Nishi, Tsuyoshi*; Yamano, Hidemasa

no journal, , 

Thermophysical properties of control rod and cladding materials are necessary to simulate the mechanism of degradation which may occur at the early stage of severe accident. In this study, surface tension of SUS316 as the cladding material was measured in molten state.

Oral presentation

Measurements of normal spectral emissivity, heat capacity and thermal conductivity of liquid SUS316

Higashi, Hideo*; Fukuyama, Hiroyuki*; Nishi, Tsuyoshi*; Yamano, Hidemasa

no journal, , 

Thermophysical properties of molten stainless steel (SUS316) are necessary to understand a core degradation mechanism in severe accidents of nuclear reactors. In this study, the normal spectral emissivity, heat capacity and thermal conductivity of liquid SUS316 were measured using an electromagnetic levitation technique in a dc magnetic field. The normal spectral emissivity has a negative wavelength dependence, and a negligible temperature dependence. The heat capacity and thermal conductivity of liquid SUS316 were measured using the noncontact laser modulation calorimetry. The heat capacity presents a constant value at a temperature range from 1661 to 1778 K. The thermal conductivity has a positive temperature dependence.

Oral presentation

Density and surface tension measurements of liquid SUS316 - 10mass%B$$_{4}$$C

Higashi, Hideo*; Fukuyama, Hiroyuki*; Yamano, Hidemasa

no journal, , 

Thermophysical properties of control rod and cladding materials are necessary to simulate the mechanism of degradation which may occur at the early stage of severe accident. In this study, density and surface tension of melt which was a mixture of SUS316 as the cladding material and 10 mass-% B$$_{4}$$C as as the control rod material were measured using an electromagnetic levitation facility.

Oral presentation

Study on Eutectic Melting Behavior of Control Rod Materials in Core Disruptive Accidents of Sodium-Cooled Fast Reactors, 1; Project Overview

Yamano, Hidemasa; Takai, Toshihide; Furukawa, Tomohiro; Emura, Yuki; Kurata, Masaki; Higashi, Hideo*; Fukuyama, Hiroyuki*; Nishi, Tsuyoshi*; Ota, Hiromichi*; Liu, X.*; et al.

no journal, , 

A research project has been started for thermophysical property evaluation of eutectic melt composed of B$$_{4}$$C as control rod material and stainless steel (SS), eutectic reaction experiments, material analysis, physical modelling of eutectic reaction and reactor application analyses in order to simulate the B$$_{4}$$C-SS eutectic melting and relocation behaviors in core disruptive accident of sodium-cooled fast reactor. This paper reports the project overview and the first year (JFY 2016) outcomes.

Oral presentation

Study on eutectic melting behavior of control rod materials in core disruptive accidents of sodium-cooled fast reactors, 4; Emissivity, heat capacity and thermal conductivity of 5mass%B$$_{4}$$C-SS eutectic molten material

Higashi, Hideo*; Fukuyama, Hiroyuki*; Yamano, Hidemasa

no journal, , 

To develop thermophysical property model to simulate eutectic reaction behavior of B$$_{4}$$C as control rod material and stainless steel (SS) in core disruptive accident of sodium-cooled fast reactor, this paper reports measurement results of density and surface tension of 5mass%B$$_{4}$$C-SS melt by droplet oscillation method and laser imaging density measurement method with very high temperature physical property measurement system (PROSPECT).

Oral presentation

Study on eutectic melting behavior of control rod materials in core disruptive accidents of sodium-cooled fast reactors, 3; Density and surface tension of 5mass%B$$_{4}$$C-SS eutectic molten material

Fukuyama, Hiroyuki*; Higashi, Hideo*; Yamano, Hidemasa

no journal, , 

To develop thermos-physical property model to simulate eutectic reaction behavior of B$$_{4}$$C as control rod material and stainless steel (SS) in core disruptive accident of sodium-cooled fast reactor, this paper reports measurement results of density and surface tension of 5mass%B$$_{4}$$C-SS melt by droplet oscillation method and laser imaging density measurement method with very high temperature physical property measurement system (PROSPECT).

Oral presentation

Thermophysical property measurement of B$$_{4}$$C-containing stainless steel melt

Fukuyama, Hiroyuki*; Higashi, Hideo*; Yamano, Hidemasa

no journal, , 

To develop thermos-physical property model to simulate eutectic reaction behavior of B$$_{4}$$C as control rod material and stainless steel (SS) in core disruptive accident of sodium-cooled fast reactor, this paper reports measurement results of thermophysical properties of B$$_{4}$$C-SS melt with very high temperature physical property measurement system (PROSPECT).

Oral presentation

Thermophysical property measurements of molten stainless steel containing 10mas%B$$_{4}$$C by electromagnetic levitation technique

Fukuyama, Hiroyuki*; Higashi, Hideo*; Yamano, Hidemasa

no journal, , 

In this study, densities, surface tensions, normal spectral emissivities, heat capacities and thermal conductivities of molten SUS316L and SUS316L containing 10mass%B$$_{4}$$C were measured by the electromagnetic levitation technique in a static magnetic field.

Oral presentation

Study on eutectic melting behavior of control rod materials in core disruptive accidents of sodium-cooled fast reactors; Project overview and progress by JFY2017

Yamano, Hidemasa; Takai, Toshihide; Furukawa, Tomohiro; Saito, Junichi; Kikuchi, Shin; Emura, Yuki; Higashi, Hideo*; Fukuyama, Hiroyuki*; Nishi, Tsuyoshi*; Ota, Hiromichi*; et al.

no journal, , 

It is necessary to simulate a eutectic melting reaction and relocation behavior of boron carbide (B$$_{4}$$C) as a control rod material and stainless steel (SS) during a core disruptive accident in an advanced sodium-cooled fast reactor designed in Japan. On that account, a new project has been started to conduct eutectic melting experiments, thermophysical property measurement of the eutectic melt, and physical model development for the eutectic melting reaction. The eutectic experiments involve the visualization experiments, eutectic reaction rate experiments and material analyses. The thermophysical properties are measured in the range of liquid and solid states. The physical model is developed for a severe accident computer code based on the measured data of the eutectic reaction rate and the physical properties. This paper describes the project overview and progress by JFY2017.

32 (Records 1-20 displayed on this page)