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山野 秀将; 江村 優軌; 高井 俊秀; 久保 重信; Quaini, A.*; Fossati, P.*; Delacroix, J.*; Journeau, C.*
Proceedings of International Conference on Nuclear Fuel Cycle (GLOBAL2024) (Internet), 4 Pages, 2024/10
本論文では、炉心混合物質の相互作用に関する反応速度論、二酸化ウラン(UO
)と鉄(Fe)と単価ホウ素(B
C)に対する高温熱物性データ、BCとステンレス鋼(SS)並びにBC-SS共晶物再配置(固化も)に関する実験研究、シビアアクシデントコードにBC-SS共晶物と反応モデルを組み込む。
佐藤 拓未; 永江 勇二; 倉田 正輝; Quaini, A.*; Gu
neau, C.*
CALPHAD; Computer Coupling of Phase Diagrams and Thermochemistry, 79, p.102481_1 - 102481_11, 2022/12
被引用回数：1 パーセンタイル：5.01(Thermodynamics)Investigation of the primary containment vessel inside the Fukushima Daiichi Nuclear Power Station showed that a significant amount of the molten corium reached the bottom of the pedestal region. The molten corium and concrete likely caused a complex interaction called Molten Corium Concrete Interaction. The solidification hysteresis of these ex-vessel debris significantly influences its properties. We performed a thermodynamic analysis using the TAF-ID database to infer the solidification path of U-Zr-Al-Ca-Si-O molten corium, which was chosen for a prototypic system of ex-vessel debris. The solidification path for the CaO-rich sim-corium showed that (i) melting as a single liquid phase above 2430 K, (ii) selective solidification of the oxide-rich corium mainly consisted of fuel materials, and (iii) solidification of the remaining materials as a silicate matrix. In contrast, the solidification path for the SiO-rich corium indicated that (i) formation of liquid miscibility gap above 2200 K between U-rich and Zr-rich oxidic melts, (ii) individual precipitation of solid phases in each liquid phase.
久保 重信; Payot, F.*; 山野 秀将; Bertrand, F.*; Bachrata, A.*; Saas, L.*; Journeau, C.*; Gosse, S.*; Quaini, A.*; 柴田 明裕*; et al.
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Sustainable Clean Energy for the Future (FR22) (Internet), 8 Pages, 2022/04
The paper presents major outcomes of the France-Japan ASTRID collaboration and the work program from 2020 to 2024 in the field of severe accident study. In the ASTRID collaboration, severe accident sequences were summarized based on the various safety analyses for the important accident phases, which contributed to strengthen the confidence in the ASTRID severe accident progression for a robust safety demonstration and identification of R&D programs of common interest. Collaborative analysis has been conducted to evaluate ASTRID mitigation device efficiency for mitigation of power excursions, material relocation, debris bed and molten pool behavior on the core catcher. The methodology for mechanical consequence assessment was also developed. In order to support the reactor studies, experimental studies have been planned and conducted regarding the reaction of core material mixtures, in-pile experiments for the fuel pin failure and material relocation through a steel duct structure, and out-of-pile experiments for the fuel coolant interaction (FCI) in the sodium pool. Severe accident analysis tool SIMMER-V with new simulation capabilities and SEASON platform have also been developed. Based on these successful achievements, several tasks to study the large fields of the severe accident domain, which include development of severe accident analysis methodologies and synthesis of SA sequences and consequences, thermodynamics, kinetic and thermo-physical studies of core material mixture, development and validation of SIMMER-V, experimental programs on the molten core material relocation and FCI. After defining the technical contents and implementation plans, the five years study programs have been started.
Quaini, A.*; Goss, S.*; Payot, F.*; Suteau, C.*; Delacroix, J.*; Saas, L.*; Gubernatis, P.*; Martin-Lopez, E.*; 山野 秀将; 高井 俊秀; et al.
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Sustainable Clean Energy for the Future (FR22) (Internet), 10 Pages, 2022/04
CEAと原子力機構は、現在の実施体制の下で新しいサブタスク、炉心混合物質における相互作用の動力学、炉心混合物質の物性、UO-Fe-BC系の高温熱力学データ、BC-SS速度論およびBC-SS共晶材料の再配置(凍結)に関する実験的研究、SIMMERコードシステムのBC/SS共晶および動力学モデル、混合物の液相化速度をモデル化するための方法論を定義した。この論文は、以前の実施協定の下での日仏協力で得られた主要な研究開発結果と、現在の協定の下での実験的および分析的ロードマップについて説明する。
Journeau, C.*; Bechta, S.*; Komlev, A.*; 倉田 正輝; 多木 寛; 松本 俊慶; Mohamad, A. B.; Barrachin, M.*; Quaini, A.*; Bottomley, D.*; et al.
no journal, ,
The OECD project TCOFF-2 (Thermodynamic Chemistry of Fission Products - Part 2) is an extension of the original project that was part of the near-term projects intended to support the Fukushima Daiichi decommissioning efforts. This second part continues to be mainly financed by Japanese Ministry (MEXT) with JAEA-CLADS support. TCOFF2 started in August 2022 and includes certain new material requirements compared to the first TCOFF project. These are increased emphasis on accident tolerant fuels (ATFs), certain actinides and fission products related to volatility/leachability but also certain combinations of the ceramic oxide systems important for MCCI behaviour. Following a PIRT review of phenomena in TCOFF 1, there was in TCOFF2 a Task 1 to prioritise current needs, particularly for relevance to severe accident phenomena and alternative materials (ATFs). This included a re-evaluation and ranking of the thermodynamic systems to make a Systems Identification and Ranking Table (SIRT) for the improvement of the thermodynamic database foreseen in TCOFF2. The further systems for evaluation were then proposed by the partners according to their particular requirements; this resulted in over 150 thermodynamic systems. In the mid-year meeting (June 2023) discussions were made to rationalise these into the most important 20 systems. The rationale for the reduction of systems to this limit will be explained in the talk, both those systems that were omitted as well as those finally included. These systems will then be used as a priority list of work for the experimental call to members that will be launched by the TCOFF-2 project towards the end of the year 2023 with the intention to initiate the first projects soon afterwards.
Journeau, C.*; Bechta, S.*; Komlev, A.*; 倉田 正輝; 多木 寛; 松本 俊慶; Mohamad, A. B.; Barrachin, M.*; Quaini, A.*; Guneau, C.*; et al.
no journal, ,
Within the second phase of the OECD/NEA project on Thermodynamic Characterisation of Fuel Debris and Fission Products Based on Scenario Analysis of Severe Accident Progression (TCOFF-2), a Systems Identification and Ranking Table (SIRT), has been derived from the usual PIRT and adapted to chemical thermodynamics and material science. Firstly, a draft list of systems of interests has been distributed to TCOFF-2 partners. After review, a final list of 154 systems has been considered. Then system ranking has been carried out. Two series of figures of merit have been considered: importance for safety including the contribution to severe accident phenomena and to fission product behaviour and source term as well as needs for further R&D, based on the lack of existing data and the needs to improve relevant existing thermodynamic databases (mostly NUCLEA and TAF-ID). Each participating organization provided ranking of the systems for these Figure of Merits. Relevance to safety has been organized in 10 columns: Classical LWR / High BU, High enrichment fuel/ Fukushima Daiichi, TMI2, Chornobyl/Near-term ATF cladding (Cr-coated Zry)/ Near-term ATF cladding (FeCrAl) /Long-term ATF cladding (SiC) /Advanced fuels (UN, U-Si) /Advanced Modular Reactors / Post-Accident Leaching). Received rankings have then been agglomerated and averaged. A dedicated finalization meeting has been held in June 2023 in which the systems having the highest relevance and the largest needs for improvement have been considered. It must be noted that some systems for which there is a rather good knowledge, like (U,O, Zr) have not been selected, nor systems in which thermodynamic results are very hard to attain due to kinetics effect such as (U,H,O). After some system grouping, consensus have been reached on a list of 20 systems (13 linked to current or near-term fuels and 7 linked to longer-term fuels) having the highest priority.
