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Yu Maruyama

Bio: Yu Maruyama is an academic researcher from Japan Atomic Energy Agency. The author has contributed to research in topics: Reactor pressure vessel & Light-water reactor. The author has an hindex of 11, co-authored 57 publications receiving 431 citations. Previous affiliations of Yu Maruyama include Japan Atomic Energy Research Institute.


Papers
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TL;DR: In this paper, the authors identify what should be clarified further about the progression of the accident at Units 1-3 through the review and analysis of information released from Tokyo Electric Power Company and government authorities, in order to contribute to establishing a new framework that pursues continuous improvement toward the highest standards of safety that can reasonably be achieved.
Abstract: An unprecedented earthquake and tsunami struck the Fukushima Dai-ichi Nuclear Power Plants on 11 March 2011. Although extensive efforts have been continuing on investigations into the causes and consequences of the accident, and the Japanese Government has presented a comprehensive report on the accident in the IAEA Ministerial Conference held in June 2011, there is still much to be clarified on what happened during the accident and why. This article aims at identifying what should be clarified further about the progression of the accident at Units 1–3 through the review and analysis of information released from Tokyo Electric Power Company and government authorities. It also discusses the safety issues raised by the accident based on the insights gained, in order to contribute to establishing a new framework that pursues continuous improvement toward the highest standards of safety that can reasonably be achieved.

91 citations

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TL;DR: In this article, a series of experiments to investigate melt-coolant interactions have been performed as part of the ALPHA program at JAERI, where melt simulating a molten core was dropped into a pool of water and volume fractions of the melt, water and steam in the mixing region prior to the occurrence of spontaneous steam explosions were quantified.

53 citations

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TL;DR: The Organisation for Economic Co-operation and Development (OECD)/Nuclear Energy Agency (NEA) Benchmark Study of the Accident at the Fukushima Daiichi Nuclear Power Station (BSAF), which started in...
Abstract: The Organisation for Economic Co-operation and Development (OECD)/Nuclear Energy Agency (NEA) Benchmark Study of the Accident at the Fukushima Daiichi Nuclear Power Station (BSAF), which started in...

34 citations

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TL;DR: The results of four experiments for the ROSA Project are briefly presented with analysis by a best-estimate (BE) code and a computational fluid dynamics (CFD) code to illustrate the capability of the LSTF and codes to simulate the thermal-hydraulic phenomena that may appear during SBLOCAs and transients as mentioned in this paper.

31 citations

Journal ArticleDOI
TL;DR: In this paper, a computer code JASMINE-pre was developed for the prediction of premixing conditions of fuel-coolant interactions and debris bed formation behavior relevant to severe accidents of light water reactors.

22 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, surface modified zirconium (Zr)-based alloys, mainly by fabricating protective coatings, are developed and evaluated as accident-tolerant fuel (ATF) claddings, aiming to improve fuel reliability and safety during normal operations, anticipated operational occurrences, and accident scenarios in water-cooled reactors.
Abstract: Abstract Surface-modified zirconium (Zr)-based alloys, mainly by fabricating protective coatings, are being developed and evaluated as accident-tolerant fuel (ATF) claddings, aiming to improve fuel reliability and safety during normal operations, anticipated operational occurrences, and accident scenarios in water-cooled reactors. In this overview, the performance of Zr alloy claddings under normal and accident conditions is first briefly summarized. In evaluating previous studies, various coating concepts are highlighted based on coating materials, focusing on their performance in autoclave hydrothermal corrosion tests and high-temperature steam oxidation tests. The challenges for the utilization of coatings, including materials selection, deposition technology, and stability under various situations, are discussed to provide some valuable guidance to future research activities.

252 citations

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TL;DR: In this paper, a two-dimensional numerical analysis of jet breakup is performed using the MPS method (Moving Particle Semi-implicit Method) which is a particle method for incompressible flows.
Abstract: A continuous jet changes to droplets where jet breakup occurs. In this study, two-dimensional numerical analysis of jet breakup is performed using the MPS method (Moving Particle Semi-implicit Method) which is a particle method for incompressible flows. The continuous fluid surrounding the jet is neglected. Dependencies of the jet breakup length on the Weber number and the Froude number agree with the experiment. The size distribution of droplets is in agreement with the Nukiyama-Tanasawa distribution that has been widely used as an experimental correlation. Effects of the Weber number and the Froude number on the size distribution are also obtained.

171 citations

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TL;DR: In this paper, three new structural models of montmorillonite with differently distributed Al/Si and Mg/Al substitutions in the tetrahedral and octahedral clay layers are systematically developed and studied by means of MD simulations to quantify the possible effects of such substitutional disorder on the swelling behavior, the interlayer structure, and mobility of aqueous species.
Abstract: Three new structural models of montmorillonite with differently distributed Al/Si and Mg/Al substitutions in the tetrahedral and octahedral clay layers are systematically developed and studied by means of MD simulations to quantify the possible effects of such substitutional disorder on the swelling behavior, the interlayer structure, and mobility of aqueous species. A very wide range of water content, from 0 to 700 mgwater/gclay is explored to derive the swelling properties of Cs–montmorillonite. The determined layer spacing does not differ much depending on the clay model. However, at low water contents up to 1-layer hydrate (∼100 mgwater/gclay) the variation of specific locations of the tetrahedral and octahedral substitutions in the two TOT clay layers slightly but noticeably affects the total hydration energy of the system. Using atom–atom radial distribution functions and the respective atomic coordination numbers we have identified for the three clay models not only the previously observed binding ...

121 citations

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TL;DR: This survey, although extensive cannot include every paper; some selection is necessary, is intended to encompass the English language heat transfer papers published in 2003, including some translations of foreign language papers.

106 citations