Distance for fragmentation of a simulated molten-core material discharged into a sodium pool

Matsuba, Ken-ichi; Isozaki, Mikio; Kamiyama, Kenji; Tobita, Yoshiharu

doi:10.1080/00223131.2015.1113897

Cited by 24 publications

(15 citation statements)

References 6 publications

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“…Instead, a scoping study of the fundamental process is an effective approach to understanding the actual situation. To date, there have been many experimental efforts under various conditions that have been aimed at clarifying the melt-coolant interaction, including UO2 into sodium (Magallon et al, 1992;Schins and Gunnerson, 1986), molten oxide into sodium (Kaiser et al, 1998;Matsuba et al, 2015;Schins and Gunnerson, 1986), molten metal into sodium (Kaiser et al, 1998;Matsuba et al, 2016a;Nishimura et al, 2010;Schins and Gunnerson, 1986), corium into water (Huhtiniemi and Magallon, 2001;Magallon, 2006;Magallon and Huhtiniemi, 2001;Spencer et al, 1994), molten oxide into water (Kaiser et al, 2001;Karbojian et al, 2009;Kudinov et al, 2013;Manickam et al, 2014Manickam et al, , 2016Moriyama et al, 2005) and molten metal into water (Abe et al, 2006;Bang et al, 2003;Bang and Kim, 2014;Bürger et al, 1995;Cho et al, 1991;Dinh et al, 1999;Iwasawa et al, 2015bIwasawa et al, , 2015cKondo et al, 1995;Mathai et al, 2015;Matsuo et al, 2008;Pillai et al, 2016;Spencer et al, 1986;Wei et al, 2016). The aim of all these experiments and tests was not limited to understanding a CDA in an SFR; a severe accident in a light-water reactor was also included as a possible scenario.…”

Section: Introductionmentioning

confidence: 99%

“…22 in Suzuki et al (2014a)]. Recently, Matsuba et al carried out experiments involving molten aluminum (Al) into sodium (Matsuba et al, 2016a) and molten alumina (Al2O3) into sodium (Matsuba et al, 2016b). Although the debris that settled onto the bottom Manuscript for Nuclear Engineering and Design of the test section could be collected after the experiments, it was difficult to visualize and observe the jet breakup process in detail.…”

Section: Introductionmentioning

confidence: 99%

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Flow transition criteria of a liquid jet into a liquid pool

Saito

Abe

Koyama

2017

Nuclear Engineering and Design

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To better understand the fundamental interactions between melt jet and coolant during a coredisruptive accident at a sodium-cooled fast reactor, the jet breakup and droplet formation in immiscible liquid-liquid systems were studied experimentally. Experiments using two different pairs of test fluids were carried out at isothermal conditions. The observed jet breakup behavior was classified into characteristic regimes based on the classical Ohnesorge classification in liquid-gas systems. The variation in breakup length obtained in the present liquid-liquid system was similar to that in a liquidgas system. The droplet size distribution in each breakup regime was analyzed using image processing and droplet formation via pinch-off, satellite formation, and entrainment was observed. The measured droplet size was compared with those available from melt jet experiments. Based on the observation and analysis results, the breakup regimes were organized on a dimensionless operating diagram, with the derived correlations representing the criteria for regime boundaries of a liquid-liquid system. Finally, the experimental data were extrapolated to the expected conditions of a sodium-cooled fast reactor. From this, it was implied that most of the hydrodynamic conditions during an accident would be close to the atomization regime, in which entrainment is the dominant process for droplet formation. Nomenclature d droplet diameter Dj0 nozzle diameter

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Flow transition criteria of a liquid jet into a liquid pool

Saito

Abe

Koyama

2017

Nuclear Engineering and Design

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“…ナトリウム冷却高速炉では，仮に炉心損傷事故(CDA)が起きたとしても溶融燃料を原子炉容器内に格納する炉容器内事象終息が達成できるように設計対策を検討している．次世代ループ型高速炉では，再臨界回避方策 (Tobita et al, 2008) が導入され，CDA シナリオは，大まかに「起因過程」，「早期流出過程」，「再配置過程」，「除熱過程」で構成される．「再配置過程」では評価手法開発 (Tobita et al, 2016) が進められてきたものの開発課題が残されており，現在，様々な研究 (Matsuba et al, 2016) が進められている．特に，中性子吸収材である炭化ホウ素 (B4C)が炉心内に混入することは反応度低減効果が大きく，「再配置過程」において再臨界ポテンシャルを更に低減するのに欠かせない重要な現象であり，将来の研究課題として摘出された (Suzuki et al, 2014)． B4C の融点は 2500 °C 程度であるが，ステンレス鋼(SS)と接触することで共晶溶融反応を起こすことが知られている (Nagase et al, 1997)．Fe-B 系では約 1200 °C が共晶点 (Massalski, 1990) であり，Fe-B-C 系でも同程度の温度で共晶により液相化する (Sudo et al, 2015) Post-test observation in Test 2014-1. The B4C block was frozen after the separation from the original position.…”

Section: 緒言unclassified

Post-test material analysis of eutectic melting reaction of boron carbide and stainless steel

Yamano

Takai

Furukawa

2020

Transactions of the JSME (In Japanese)

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It is necessary to simulate a eutectic melting reaction and relocation behavior of boron carbide (B4C) as a control rod material and stainless steel (SS) during a core disruptive accident in an advanced sodium-cooled fast reactor designed in Japan because the B4C-SS eutectic relocation behavior has a large uncertainty in the reactivity history based on a simple calculation. A physical model simulating the eutectic melting reaction and relocation was developed and implemented into a severe accident simulation code. The developed model must be validated by using test data. To validate the physical model, therefore, the visualization tests of SS-B4C eutectic melting reaction was carried out by contacting SS melts of several kg with a B4C pellet heated up to about 1500 °C. The tests have shown the eutectic reaction visualization as well as freezing and relocation of the B4C-SS eutectic in upper part of the solidified test piece due to the density separation. Post-test material analyses by using X-ray diffraction and transmission electron microscope techniques have indicated that FeB appeared at the B4C-SS contact interface and (Fe,Cr)2B at the top surface of the test piece. Glow discharge optical emission spectrometry has been applied to quantitative analysis of boron concentration distributions. The boron concentration was high at the upper surface and near the original position of the B4C pellet.

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“…Certain experiments have been performed in the past to understand the interaction phenomenology of oxidic (UO 2 ) and/or metallic fuel materials with sodium. Some of the experiments used simulants, such as alumina for UO 2 [11] and aluminium for metallic fuel [12] to study the interaction mechanism, while some used prototypic corium. Due to large differences that exist between alumina and prototypic corium [13], the representativeness of this system is questionable.…”

Section: Review Of the Past Experimentsmentioning

confidence: 99%

Modelling of X-Ray Radioscopy for Phase Topology Estimation During Corium Sodium Interaction

Singh

Cassiaut-Louis

Journeau

et al. 2018

Volume 9: Student Paper Competition

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In case of a severe accident scenario in a Sodium cooled Fast Reactor (SFR) such as the ASTRID demonstrator, the fuel might melt and interact with the coolant i.e. liquid sodium. This molten Fuel Coolant Interaction (FCI) can generate an energetic vapor explosion that can jeopardize the reactor structures. The yield of the vapor explosion is strongly dependent on the local distribution of the fragmented melt with respect to the local vapor fractions. The medium is composed of three phases, i.e. corium, liquid sodium and vapor sodium. Thus, a study of the three phase distribution within the system is a key to understand the extent of the explosion. PLINIUS-2, the future large mass experimental platform of CEA Cadarache will be dedicated to conducting experiments to understand the behavior of prototypic corium in case of severe accidents. In order to study these interactions, a high energy X-ray imaging system is being developed. This system consists of a 15 MeV Linear accelerator producing high energy X-rays with significantly high flux, which are attenuated as it passes through the highly dense test section. The transmitted radiation is detected and re-emitted as visible light by the GADOX screen coupled to the CMOS camera. Using this system to study the interaction between corium and sodium is particularly challenging due to the small corium particulates of the size of the order of 1 mm. The qualification of the foreseen radioscopy system on the visualization of such an interaction requires the development of physical phantoms. This paper presents the preliminary simulations of expected images of corium fragments in sodium, vapor bubbles and vapor film around the fragments. The simulations are carried out using a CEA Cadarache in-house tool MODHERATO, which produces radiographic images in satisfactory agreement with the real time imaging. The simulation of particles is based on the knowledge of interaction phenomenology gained from past experiments and on the statistical analysis of the size of corium particles formed. The models which, according to MODHERATO results, qualify to be detected and resolved, help manufacturing physical phantoms to conduct the experiments.

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Distance for fragmentation of a simulated molten-core material discharged into a sodium pool

Cited by 24 publications

References 6 publications

Flow transition criteria of a liquid jet into a liquid pool

Flow transition criteria of a liquid jet into a liquid pool

Post-test material analysis of eutectic melting reaction of boron carbide and stainless steel

Modelling of X-Ray Radioscopy for Phase Topology Estimation During Corium Sodium Interaction

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