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Journal Articles

Study on eutectic melting behavior of control rod materials in core disruptive accidents of sodium-cooled fast reactors; Project overview and progress until JFY2022

Yamano, Hidemasa; Takai, Toshihide; Emura, Yuki; Fukuyama, Hiroyuki*; Nishi, Tsuyoshi*; Morita, Koji*; Nakamura, Kinya*; Pellegrini, M.*

Nihon Kikai Gakkai 2023-Nendo Nenji Taikai Koen Rombunshu (Internet), 5 Pages, 2023/09

A research project has been conducting thermophysical property measurement of a eutectic melt, eutectic melting reaction and relocation experiments, eutectic reaction mechanism investigation, and physical model development on the eutectic melting reaction for reactor application analysis in order to simulate the eutectic melting reaction and relocation behavior of boron carbide as a control rod material and stainless steel during a core disruptive accident in an advanced sodium-cooled fast reactor designed in Japan. This paper describes the project overview and progress until JFY2022.

Journal Articles

Raman spectroscopy of eutectic melting between boride granule and stainless steel for sodium-cooled fast reactors

Fukai, Hirofumi*; Furuya, Masahiro*; Yamano, Hidemasa

Nuclear Engineering and Technology, 55(3), p.902 - 907, 2023/03

 Times Cited Count:1 Percentile:0.01(Nuclear Science & Technology)

This paper addresses reaction products and their distribution of the eutectic melting/solidifying reaction of boron carbide (B$$_{4}$$C) and stainless-steel (SS). The influence of the existence of carbon on the B$$_{4}$$C-SS eutectic reaction was investigated by comparing the iron boride (FeB)-SS reaction by Raman spectroscopy with Multivariate Curve Resolution (MCR) analysis. The scanning electron microscopy with dispersive X-ray spectrometer was also used to investigate the elemental information of the pure metals such as Cr, Ni, and Fe. In the B$$_{4}$$C-SS samples, a new layer was formed between B$$_{4}$$C/SS interface, and the layer was confirmed that the formed layer corresponded to amorphous carbon (graphite) or FeB or Fe$$_{2}$$B. In contrast, a new layer was not clearly formed between FeB and SS interface in the FeB-SS samples.

Journal Articles

Experimental study on reaction behavior between control rod material and molten stainless steel for core disruptive accidents of sodium-cooled fast reactors

Emura, Yuki; Kamiyama, Kenji; Yamano, Hidemasa

Dai-26-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (Internet), 4 Pages, 2022/07

no abstracts in English

JAEA Reports

Development of high temperature LBE corrosion test loop "OLLOCHI"

Saito, Shigeru; Wan, T.*; Okubo, Nariaki; Kita, Satoshi*; Obayashi, Hironari; Sasa, Toshinobu

JAEA-Technology 2021-034, 94 Pages, 2022/03

JAEA-Technology-2021-034.pdf:5.91MB

Lead-bismuth eutectic alloy (LBE) is a major candidate for a spallation target material and core coolant of an accelerator driven system (ADS) which has been developed in the Japan Atomic Energy Agency (JAEA) to transmute high-level radioactive wastes. A proton irradiation facility to build a material irradiation database for future ADS development is under considering in the J-PARC. To realize both the ADS and the above-mentioned facility, there are many issues on operational safety of LBE to be solved. Especially, corrosion data for the major materials such as T91 (Modified 9Cr-1Mo steel) and SS316L at the temperature range between 400 and 550 $$^{circ}$$C under the conditions of flowing LBE with a controlled oxygen are not sufficient to design the ADS and the facility. JAEA developed a new large-scale corrosion test loop named "OLLOCHI (Oxygen-controlled LBE LOop for Corrosion tests in HIgh-temperature)" aiming to perform the compatibility tests between the LBE and the steels, as well as to develop the LBE operation technology. OLLOCHI has a function to automatically control the oxygen concentration in LBE. The maximum temperature at the regions of high-temperature and low-temperature of the OLLOCHI are 550 $$^{circ}$$C and 450 $$^{circ}$$C respectively to cover the ADS designed condition. As a result of 2,000 hours operation, it was demonstrated that the OLLOCHI showed the designed performance. In this report, outline of the OLLOCHI, details of the components, results of characteristic tests, and the future experimental plan are described.

Journal Articles

Flow measurement in high temperature liquid metal by using electro-magnet probe

Ariyoshi, Gen; Obayashi, Hironari; Saito, Shigeru; Sasa, Toshinobu

Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 10 Pages, 2022/03

To clarify the flow characteristics of heavy liquid-metal (HLM) is important to achieve the construction of nuclear transmutation facility that utilizes HLM as a spallation target and coolant. At present, lead-bismuth eutectic (LBE) spallation target plans to be installed in Japan proton accelerator research complex (J-PARC). LBE is also selected as one of the candidate media of a spallation target and a coolant for innovative nuclear systems such as accelerator-driven system (ADS) and LBE-cooled fast reactor, due to its adequate physical/chemical properties. The characteristics of LBE flowing inside the target are usually clarified with computational fluid dynamics analysis since the measurement techniques for the HLM flow are not well established, especially for high temperature region over 450$$^{circ}$$C that is delivered from ADS's criteria. Therefore, the objective of this study is to develop measurement method for flow characteristics in the high temperature LBE. A miniature electro-magnet is introduced to electro-magnetic probe to overcome the limitation caused by a curie temperature of permanent magnet. To evaluate performance of the new probe, experimental apparatus equipping annular rotating vessel were also manufactured. The new probe was applied to high temperature LBE up to 480$$^{circ}$$C. As a result, proportional induced voltage to the rotation speed of LBE were clearly observed, where excitation currents of the miniature electro-magnet were 0.2 A or 1 A. In this paper, configuration and performance of the newly developed electro-magnet probe to the high temperature LBE will be presented.

Journal Articles

Status of LBE study and experimental plan at JAEA

Saito, Shigeru; Wan, T.*; Okubo, Nariaki; Obayashi, Hironari; Watanabe, Nao; Ohdaira, Naoya*; Kinoshita, Hidetaka; Yamaki, Kenichi*; Kita, Satoshi*; Yoshimoto, Hidemitsu*; et al.

JPS Conference Proceedings (Internet), 33, p.011041_1 - 011041_6, 2021/03

An Accelerator Driven System (ADS) for waste transmutation investigated in JAEA employs lead-bismuth eutectic (LBE) as a neutron production target material and coolant. The neutrons are to be produced via the spallation with 1.5 GeV proton beam injection. As materials irradiation data are important for ADS development, JAEA plans to construct an irradiation facility with LBE neutron production target in J-PARC. There are many technical issues on LBE for practical use. In JAEA, various R&Ds are being carried out. Concerning corrosion study, conditioning operation and functional tests of OLLOCHI started. Oxygen concentration control technology has also developing. In the large scale LBE loop experiment, the operation for steady state and transient experiments was performed by using IMMORTAL. In the area of instrument, development of ultrasonic flow meter and freeze seal valve are progressing as a key technology for the LBE loop system. Investigation of behavior of impurities in LBE, which is important for design of the irradiation facility, started. In this paper, the status of the LBE studies and experimental plan will be presented.

Journal Articles

Characterization of mechanical strain induced by lead-bismuth eutectic (LBE) freezing in stainless steel cup

Ohdaira, Naoya*; Saito, Shigeru

Heliyon (Internet), 6(2), p.e03429_1 - e03429_8, 2020/02

 Times Cited Count:4 Percentile:39.14(Multidisciplinary Sciences)

Lead-bismuth eutectic (LBE) is a candidate liquid metal coolant for a fast reactor, especially accelerator driven system (ADS). Freeze sealed valve is a candidate design to be possible to add passive safety to the reactor. On the other hand, since LBE is known that it causes expansion after its solidification, quantitative evaluation of the stress to the pipe produced by the LBE expansion should be considered. Many researchers produced related data for the expansion, however, evaluations of the strain by LBE expansion was barely reported. Therefore, the strain measurement using a stainless steel cup and the stress evaluation was performed together with visual observation using an optical microscopy. The results indicated keeping above room temperature (RT) was a significantly effective way to reduce the strain to the pipe.

Journal Articles

Study on eutectic melting behavior of control rod materials in core disruptive accidents of sodium-cooled fast reactors, 5; Validation of a multi-phase model for eutectic reaction between molten stainless steel and B$$_{4}$$C

Liu, X.*; Morita, Koji*; Yamano, Hidemasa

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.47 - 51, 2019/09

Investigation of the eutectic reaction in a core disruptive accident of sodium cooled reactor is of importance since reactor criticality will be affected by the change in reactivity after eutectic reaction. In this study, we performed 1st step of validation analysis using a fast reactor safety analysis code, SIMMER-III, with the developed model based on a new series of experiments, where a B$$_{4}$$C pellet was immersed into a molten stainless steel (SS) pool. The simulation results showed the general behavior of eutectic material formation measured in the experiments reasonably. The eutectic reaction consumes solid B$$_{4}$$C and liquid SS, and then the liquid eutectic composition is produced at the early stage of reaction due to the high temperature of molten SS. Movement of the eutectic material in the molten pool leads to the redistribution of boron element. Molten SS pool then freezes to solid SS and movement of eutectic material is stopped by surrounding solid SS. Boron concentration in the pool was measured after molten SS freezes into a solid. Simulation results indicate that boron tends to accumulate in the upper part of the molten pool. This is attributed to the buoyancy force acting on lighter boron in the molten SS pool. A parametric study was also conducted by changing the initial temperature of B$$_{4}$$C pellet and SS to investigate the temperature sensitivity on the eutectic reaction behavior.

Journal Articles

Phenomenology of BWR fuel assembly degradation

Kurata, Masaki; Barrachin, M.*; Haste, T.*; Steinbrueck, M.*

Journal of Nuclear Materials, 500, p.119 - 140, 2018/03

 Times Cited Count:29 Percentile:66.35(Materials Science, Multidisciplinary)

Severe accidents occurred at the Fukushima-Daiichi Nuclear Power Station (FDNPS) required an immediate re-examination of fuel degradation phenomenology. The present paper reviews the updated knowledge on the phenomenology of the fuel degradation, focusing mainly on the BWR fuel assembly degradation at the macroscopic scale and that of the individual interactions at the meso-scale. Oxidation of boron carbide (B$$_{4}$$C) control rods potentially generate far larger amounts of heat and hydrogen under BWR accident conditions. All integral tests with B$$_{4}$$C control rods or control blades have shown early failure, liquefaction, relocation and oxidation of B$$_{4}$$C starting at temperatures around 1250$$^{circ}$$C, well below the significant interaction temperatures of UO$$_{2}$$-Zry. These interactions or reactions potentially influence the progress of fuel degradation in the early phase. The steam-starved conditions, which are being discussed as a likely scenario at the FDNPS accident, highly influence the individual interactions and potentially lead the fuel degradation in non-prototypical directions. The detailed phenomenology of individual interactions and their influence on the transient and on the late phase of the severe accidents are also discussed.

Journal Articles

Surface decoration of stainless steel for LBE flow measurement by ultrasonic techniques

Kikuchi, Kenji; Tezuka, Masao*; Saito, Shigeru; Oigawa, Hiroyuki; Takeda, Yasushi*

Proceedings of 4th International Symposium on Ultrasonic Doppler Method for Fluid Mechanics and Fluid Engineering (ISUD-4), p.107 - 110, 2004/09

When the steel is submerged into LBE, LBE will contact with the steel except for the interface among LBE, gas and metal where the surface energy controls the shape of the free surface in LBE. It is supposed that LBE will transmit ultrasonic wave into LBE through the contacting area. However, the ultrasonic echo was too low to detect from the steel container filled with LBE. The measurement was improved by coating the interface between the steel and LBE with the SnPb solder. After an immersion test the steel surface was covered with thin LBE layer. The thickness of the layer is only 10 to 20 micron m. So it will not disturb the flow pattern where UVP is applied. Sn was not detected by X ray analyses. This is an evidence how the steel was wetted in LBE and how the ultrasonic wave transmitted though the interface of LBE and the steel.

Journal Articles

Studies in the PuO$$_{2}$$-ZrO$$_{2}$$ pseudo-binary phase diagram

Albiol, T.*; Serizawa, Hiroyuki; Arai, Yasuo

Journal of Nuclear Science and Technology, 39(Suppl.3), p.834 - 837, 2002/11

no abstracts in English

JAEA Reports

Behavior of radionuclide release from irradiated fuel under severe accident conditions; Results of VEGA-1 test

Hidaka, Akihide; Nakamura, Takehiko; Kudo, Tamotsu; Uetsuka, Hiroshi

JAERI-Research 2001-055, 48 Pages, 2001/12

JAERI-Research-2001-055.pdf:3.9MB

no abstracts in English

Journal Articles

Electrode reaction of the Np$$^{3+}$$/Np couple in LiCl-KCl eutectic melts

Shirai, Osamu; Iizuka, Masatoshi*; Iwai, Takashi; Arai, Yasuo

Journal of Applied Electrochemistry, 31(9), p.1055 - 1060, 2001/09

 Times Cited Count:22 Percentile:47.09(Electrochemistry)

no abstracts in English

Journal Articles

Recovery of Neptunium by electrolysis of NpN in LiCl-KCl eutectic melts

Shirai, Osamu; Iizuka, Masatoshi*; Iwai, Takashi; Suzuki, Yasufumi; Arai, Yasuo

Journal of Nuclear Science and Technology, 37(8), p.676 - 681, 2000/08

no abstracts in English

Journal Articles

Electrolysis of plutonium nitride in LiCl-KCl eutectic melts

Shirai, Osamu; Iwai, Takashi; Shiozawa, Kenichi; Suzuki, Yasufumi; Sakamura, Y.*; Inoue, Tadashi*

Journal of Nuclear Materials, 277(2-3), p.226 - 230, 2000/02

 Times Cited Count:24 Percentile:80.77(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Development of plutonium recovery process by molten salt electrorefining with liquid cadmium cathode

Iizuka, Masatoshi*; Uozumi, Koichi*; Inoue, Tadashi*; Iwai, Takashi; Shirai, Osamu; Arai, Yasuo

Proceedings of 6th International Exchange Meeting on Actinide and Fission Product Partitioning and Transmutation (CD-ROM), p.327 - 341, 2000/00

no abstracts in English

Journal Articles

Studies on pyrochemical reprocessing for metallic and nitride fuels; Behavior of transuranium elements in LiCl-KCl/liquid metal systems

Sakamura, Y.*; Inoue, Tadashi*; Shirai, Osamu; Iwai, Takashi; Arai, Yasuo; Suzuki, Yasufumi

Proc. of the Int. Conf. on Future Nuclear Systems (GLOBAL'99)(CD-ROM), 8 Pages, 1999/00

no abstracts in English

Journal Articles

Oral presentation

Research on physicochemical composition of spallation products in lead-bismuth eutectic in ADS, 1; Estimation of inventories of spallation products

Maekawa, Fujio; Matsuda, Hiroki; Meigo, Shinichiro; Sasa, Toshinobu; Miyahara, Shinya*; Arita, Yuji*; Ohdaira, Naoya*

no journal, , 

To assess physicochemical composition of spallation products in Lead-Bismuth Eutectic (LBE) alloy which was to be used as a spallation neutron target and coolant materials of Accelerator Driven nuclear transmutation Systems (ADS), inventories of spallation products in an LBE loop of J-PARC ADS Target Test Facility (TEF-T) were evaluated.

50 (Records 1-20 displayed on this page)