Development of a new crust model for analyzing VULCANO VBS-U3 mcci experiment with MPS method

Yamada, Takeshi*; Li, X.; Yamashita, Takuya; Yamaji, Akifumi*

Proceedings of 31st International Conference on Nuclear Engineering (ICONE31) (Internet), 10 Pages, 2024/11

https://doi.org/10.1115/ICONE31-134499

In this study, a new crust model is being developed to analyze MCCI, which involves continuous concrete ablation with presence of the crust layer between the corium and the concrete walls, which may gradually move with the slow concrete wall ablation process over long time. The new crust model must enable accumulation of physical displacement of the crust particle over long time (i.e., enable physical creeping) while preventing accumulation of numerical displacement of the crust particles over long time (i.e., preventing numerical creeping), Hence, in the new crust model, the PS has been effectively disabled for the crust particles. Qualitative validity of such numerical modeling was confirmed through some trial analyses of VULCANO-VBS test using a set of tentative calculation conditions and parameters, which should be carefully revised for future quantitative discussions including validation of the analysis results with experimental results.

Estimation of the in-depth debris status of Fukushima Unit-2 and Unit-3 with Multi-physics modeling (Contract research); FY2021 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Waseda University*

JAEA-Review 2022-054, 150 Pages, 2023/02

JAEA-Review-2022-054.pdf:7.26MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2021. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (hereafter referred to "1F"). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2019, this report summarizes the research results of the "Estimation of the in-depth debris status of Fukushima Unit-2 and Unit-3 with multi-physics modeling" conducted from FY2019 to FY2021. Since the final year of this proposal was FY2021, the results for three fiscal years were summarized. Continuous update on understanding of the damaged 1F reactors is important for safe and efficient decommissioning of the reactors. This study aimed to estimate the in-depth debris status of the damaged 1F Unit-2 and Unit-3 through multi-physics modeling, which comprises of MPS method, simulated molten debris relocation experiment and high-temperature melt property data acquisition in the three-year project from FY2019.

Estimation of the in-depth debris status of Fukushima Unit-2 and Unit-3 with Multi-physics modeling (Contract research); FY2020 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Waseda University*

JAEA-Review 2021-034, 107 Pages, 2021/12

JAEA-Review-2021-034.pdf:6.08MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2020. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station (1F), Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2019, this report summarizes the research results of the "Estimation of the in-depth debris status of Fukushima Unit-2 and Unit-3 with multi-physics modeling" conducted in FY2020. Continuous update on understanding of the damaged 1F reactors is important for safe and efficient decommissioning of the reactors. This study aims to estimate the in-depth debris status of the damaged 1F Unit-2 and Unit-3 through multi-physics modeling, which comprises of MPS method, simulated molten debris relocation experiment and high-temperature melt property data acquisition in the three-year project from FY2019.

Chapter 18, Moving particle semi-implicit method

Wang, Z.; Duan, G.*; Koshizuka, Seiichi*; Yamaji, Akifumi*

Nuclear Power Plant Design and Analysis Codes, p.439 - 461, 2021/00

https://doi.org/10.1016/B978-0-12-818190-4.00018-8

Study on loss-of-cooling and loss-of-coolant accidents in spent fuel pool; Confirmation of fuel temperature calculation function with oxidation reaction in the SAMPSON code

Suzuki, Hiroaki*; Morita, Yoshihiro*; Naito, Masanori*; Nemoto, Yoshiyuki; Kaji, Yoshiyuki

Mechanical Engineering Journal (Internet), 7(3), p.19-00450_1 - 19-00450_17, 2020/06

https://doi.org/10.1299/mej.19-00450

In this study, the SAMPSON code was modified to evaluate severe accidents in a spent fuel pool (SFP). Air oxidation models based on oxidation data obtained on the Zircaroy-4 cladding (ANL model) and the Zircaroy-2 cladding (JAEA model) were included in the modified SAMPSON code. Experiments done by Sandia National Laboratory using simulated fuel assemblies equivalent to those of an actual BWR plant were analyzed by the modified SAMPSON code to confirm the functions for analysis of the severe SFP accidents. The rapid fuel rod temperature rise due to the Zr air oxidation reaction could be reasonably evaluated by the SAMPSON analysis. The SFP accident analyses were conducted with different initial water levels which were no water, water level at bottom of active fuel, and water level at half of active fuel. The present analysis showed that the earliest temperature rise of the fuel rod surface occurred when there was no water in the SFP and natural circulation of air became possible.

Development status of data acquisition system for IFMIF/EVEDA accelerator

Usami, Hiroki; Takahashi, Hiroki; Komukai, Satoshi*

Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.760 - 763, 2015/09

http://www.pasj.jp/web_publish/pasj2015/proceedings/PDF/WEP1/WEP101.pdf

EU and JAEA are advancing development of Linear IFMIF Prototype Accelerator (LIPAc) control system jointly, but JAEA keeps developing central control system (CCS) mainly. Data transfer during an equipment control system of CCS and EU is performed through EPICS. JAEA is using PostgreSQL as 1 of development elements in CCS and is advancing development of the system to record the whole EPICS data of LIPAc (the data acquisition system). On the other hand, a data acquisition is performed using BEAUTY (Best Ever Archive Toolset, yet) in an element test of equipment at Europe. Therefore "1 client refers to collected data by more than one server machine" with "compatibility securement of data with BEAUTY" in case of development of the data acquisition system of CCS, and, it's necessary to consider "To do a data acquisition and backup work at the same time". For the moment, former 2 are in progress. And a demonstration of the data acquisition system is being performed simultaneously with commissioning in injector. The data acquisition system is collecting data of injector other ones, and the data reference by a monitor with CSS (Control System Studio) is also possible. We will report on the current state of the development of the data acquisition system by making reference to a result of the test by injector commissioning.

SCDAP/RELAP5 analysis of station blackout with pump seal LOCA in Surry plant

Hidaka, Akihide; Soda, Kunihisa; Sugimoto, Jun

Journal of Nuclear Science and Technology, 32(6), p.527 - 538, 1995/06

https://doi.org/10.3327/jnst.32.527

no abstracts in English

Numerical evaluation of general n-dimensional integrals by the repeated use of Newton-Cotes formulas

Nihira, Takeshi*; Iwata, Tadao

JAERI-M 92-099, 28 Pages, 1992/07

JAERI-M-92-099.pdf:0.64MB

no abstracts in English

Rotational test of ceramic reactor for vacuum pump

Abe, Tetsuya; Murakami, Yoshio; Takazawa, Kunio*;

Shinku, 31(5), p.334 - 337, 1988/00

https://doi.org/10.3131/jvsj.31.334

no abstracts in English

Heat Loss and Fluid Leakage Tests of the ROSA-III Facility

; Tasaka, Kanji;

JAERI-M 9834, 42 Pages, 1981/12

JAERI-M-9834.pdf:0.92MB

no abstracts in English