Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 38

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Development of a formulation to predict molten core spreading in an LWR severe accident

Sahboun, N. F.; Matsumoto, Toshinori; Iwasawa, Yuzuru; Wang, Z.; Sugiyama, Tomoyuki

Annals of Nuclear Energy, 195, p.110145_1 - 110145_12, 2024/01

 Times Cited Count:1 Percentile:41.04(Nuclear Science & Technology)

Journal Articles

Compact moving particle semi-implicit method for incompressible free-surface flow

Wang, Z.; Matsumoto, Toshinori; Duan, G.*; Matsunaga, Takuya*

Computer Methods in Applied Mechanics and Engineering, 414, p.116168_1 - 116168_49, 2023/09

 Times Cited Count:5 Percentile:82.90(Engineering, Multidisciplinary)

Journal Articles

Improvement of JASMINE code for ex-vessel molten core coolability in BWR

Matsumoto, Toshinori; Kawabe, Ryuhei*; Iwasawa, Yuzuru; Sugiyama, Tomoyuki; Maruyama, Yu

Annals of Nuclear Energy, 178, p.109348_1 - 109348_13, 2022/12

 Times Cited Count:1 Percentile:19.69(Nuclear Science & Technology)

The Japan Atomic Energy Agency extended the applicability of their fuel-coolant interaction analysis code JASMINE to simulate the relevant phenomena of molten core in a severe accident. In order to evaluate the total coolability, it is necessary to know the mass fraction of particle, agglomerated and cake debris and the final geometry at the cavity bottom. An agglomeration model that considers the fusion of hot particles on the cavity floor was implemented in the JASMINE code. Another improvement is introduction of the melt spreading model based on the shallow water equation with consideration of crust formation at the melt surface. For optimization of adjusting parameters, we referred data from the agglomeration experiment DEFOR-A and the under-water spreading experiment PULiMS conducted by KTH in Sweden. The JASMINE analyses reproduced the most of the experimental results well with the common parameter set, suggesting that the primary phenomena are appropriately modelled.

Journal Articles

Melt impingement on a flat spreading surface under wet condition

Sahboun, N. F.; Matsumoto, Toshinori; Iwasawa, Yuzuru; Sugiyama, Tomoyuki

Proceedings of Asian Symposium on Risk Assessment and Management 2021 (ASRAM 2021) (Internet), 15 Pages, 2021/10

Journal Articles

Development of evaluation framework for ex-vessel core coolability

Matsumoto, Toshinori; Iwasawa, Yuzuru; Sugiyama, Tomoyuki

Proceedings of Reactor core and Containment Cooling Systems, Long-term management and reliability (RCCS 2021) (Internet), 8 Pages, 2021/10

A methodological framework is being developed in JAEA for evaluating debris coolability at ex-vessel during the severe accident (SA) of BWR under the wet cavity strategy. The probability of ex-vessel debris coolability under the wet cavity strategy is analyzed to demonstrate the evaluation approach. Probabilistic distribution of the melt conditions ejected from the RPV was obtained as the result of the iterative analyses with MELCOR code. Five uncertainty parameters relating with the core degradation and transfer process were chosen. Parameter sets were generated by Latin hypercube sampling (LHS). JASMINE code plays the physical model to predict the mass fraction of agglomerated debris and melt pool spreading on the floor. Fifty-nine input parameter set for JASMINE code were generated by LHS again using the probabilistic distribution of melt condition determined from the results of MELCOR analyses. The depth of the water pool was set as 0.5, 1.0 and 2.0 m. The accumulated debris height was compared with the criterion to judge the debris coolability. As the result, the success probability of debris cooling was obtained through the sequence of calculations.

Journal Articles

The Analysis for Ex-Vessel debris coolability of BWR

Matsumoto, Toshinori; Iwasawa, Yuzuru; Ajima, Kohei*; Sugiyama, Tomoyuki

Proceedings of Asian Symposium on Risk Assessment and Management 2020 (ASRAM 2020) (Internet), 10 Pages, 2020/11

The probability of ex-vessel debris coolability under the wet cavity strategy is analyzed. The first step is the uncertainty analyses by severe accident analysis code MELCOR to obtain the melt condition. Five uncertain parameters which are relating with the core degradation and transfer process were chosen. Input parameter sets were generated by LHS. The analyses were conducted and the conditions of the melt were obtained. The second step is the analyses for the behavior of melt under the water by JASMINE code. The probabilistic distribution of parameters are determined from the results of MELCOR analyses. Fifty-nine parameter sets were generated by LHS. The depth of water pool is set to be 0.5, 1.0 and 2.0 m. Debris height were compared with the criterion to judge the debris coolability. As the result, the success probability of debris cooling was obtained through the sequence of calculations. The technical difficulties of this evaluation method are also discussed.

Journal Articles

Experimental and analytical investigation of formation and cooling phenomena in high temperature debris bed

Hotta, Akitoshi*; Akiba, Miyuki*; Morita, Akinobu*; Konovalenko, A.*; Vilanueva, W.*; Bechta, S.*; Komlev, A.*; Thakre, S.*; Hoseyni, S. M.*; Sk$"o$ld, P.*; et al.

Journal of Nuclear Science and Technology, 57(4), p.353 - 369, 2020/04

 Times Cited Count:14 Percentile:68.28(Nuclear Science & Technology)

Journal Articles

CFD analysis of hydrogen flame acceleration with burning velocity models

Motegi, Kosuke; Trianti, N.; Matsumoto, Toshinori; Sugiyama, Tomoyuki; Maruyama, Yu

Proceedings of 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-18) (USB Flash Drive), p.4324 - 4335, 2019/08

Journal Articles

Fluid dynamic analysis on hydrogen deflagration in vertical flow channel with annular obstacles

Matsumoto, Toshinori; Sato, Masatoshi; Sugiyama, Tomoyuki; Maruyama, Yu

Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 6 Pages, 2017/07

Journal Articles

Thermofluid dynamic analysis for THAI tests with passive hydrogen recombiner

Sato, Masatoshi; Matsumoto, Toshinori; Sugiyama, Tomoyuki; Maruyama, Yu

Proceedings of 8th European Review Meeting on Severe Accident Research (ERMSAR 2017) (Internet), 12 Pages, 2017/05

Journal Articles

Analysis with CFD code for THAI test on thermal-hydraulics during PAR activation

Sato, Masatoshi; Matsumoto, Toshinori; Sugiyama, Tomoyuki; Maruyama, Yu

Proceedings of 10th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-10) (USB Flash Drive), 10 Pages, 2016/11

Journal Articles

Improvement of ex-vessel molten core behavior models for the JASMINE code

Matsumoto, Toshinori; Kawabe, Ryuhei; Sugiyama, Tomoyuki; Maruyama, Yu

Proceedings of 10th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-10) (USB Flash Drive), 9 Pages, 2016/11

During severe accident at nuclear power stations, molten core material jet could be discharged from the reactor pressure vessel into the water pool formed at the pedestal or cavity in the containment vessel. To improve the JASMINE code, The method for determining particle diameters which follow the Rosin-Rammler distribution was implemented. The jet breakup experiments, DEFOR-A conducted by KTH (Royal Institute of Technology, Sweden) were analyzed with the code. The influence of the experimental conditions, such as water subcooling, melt jet diameter and superheat were discussed. A crust layer formation model was also implemented in the code. The analyses using the model were carried out for the melt spreading experiments, PULiMS conducted by KTH. The spreading area was overestimated. Further improvement of the melt spreading model were discussed to close the gaps by introducing additional models such as heat conduction in the substrate materials, void formed inside the melt and so on.

Journal Articles

Analysis for progression of accident at Fukushima Dai-ichi Nuclear Power Station with THALES2 code

Matsumoto, Toshinori; Ishikawa, Jun; Maruyama, Yu

Proceedings of 16th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-16) (USB Flash Drive), p.4033 - 4043, 2015/08

Journal Articles

Estimation of heat transfer coefficient and flow characteristics on heat transfer tube in sodium-water reaction

Matsumoto, Toshinori*; Takata, Takashi*; Yamaguchi, Akira*; Kurihara, Akikazu; Ohshima, Hiroyuki

Journal of Nuclear Science and Technology, 48(3), p.315 - 321, 2011/03

 Times Cited Count:1 Percentile:10.53(Nuclear Science & Technology)

In the steam generator of a sodium-cooled fast reactor, when the tube fails, water leaks into the sodium stream and sodium-water reaction is initiated. In the present study, a numerical analysis has been carried out to determine the heat transfer coefficient from temperature data obtained in a sodium-water reaction experiment. By updating the heat transfer coefficient, an inverse problem of heat transfer has been solved in the analysis based on the result of the SWAT-1R experiment. It is found that the heat transfer coefficient fluctuates largely during the reaction. The heat transfer coefficient is affected by the flow characteristics. Hence, we characterize the flow pattern near the heat transfer tube at typical periods in the phenomenon progression.

Journal Articles

Numerical study on correlation of heat transfer coefficient with void fraction at heat transfer tube surface in sodium water reaction

Matsumoto, Toshinori*; Takata, Takashi*; Yamaguchi, Akira*; Kurihara, Akikazu; Ohshima, Hiroyuki

Proceedings of 13th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-13) (CD-ROM), 10 Pages, 2009/09

When a heat transfer tube fails in steam generator (SG) of sodium-cooled fast reactor (SFR), sodium-water reaction (SWR) would take place. It is significant for estimation of the heat transfer from the fluid to the tube wall during SWR region to evaluate the possibility of the secondary tube failure in case of overheating rupture. In the present study, thermal hydraulics simulation of the fluid around the tube is conducted. The heat transfer coefficient is computed, the correlation diagram between the heat transfer coefficient and the void fraction has been obtained. The void fraction around the heat transfer tube in the SWR has been evaluated.

Journal Articles

Estimation of heat transfer coefficient and flow characteristics on heat transfer tube in sodium water reaction

Matsumoto, Toshinori*; Takata, Takashi*; Yamaguchi, Akira*; Kurihara, Akikazu; Ohshima, Hiroyuki

Proceedings of 6th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-6) (USB Flash Drive), 6 Pages, 2008/11

In a steam generator of sodium-cooled fast reactor, high temperature reacting jet is generated when a heat transfer tube fails and it might cause a secondary fauilure of neighboring tubes due to tube deterioration. Quantification of heat transfer from fluid to the tube is important perspective of safety evaluation. In this study, the heat transfer coefficient on the heat transfer tube under sodium-water reaction phenomena was numerically estimated based on the temperature measured in a sodium experiment using SWAT-1R test facility of JAEA. Furthermore, the floa characteristics on the heat transfer tube was investigated taking into account the variation of the heat transfer coefficient.

Oral presentation

Compact MPS method with high accuracy and computational efficiency

Wang, Z.; Matsumoto, Toshinori

no journal, , 

The moving particle semi-implicit (MPS) method has been widely applied to nuclear severe accident analyses due to its unique meshless framework and Lagrangian nature in capturing moving interfaces or phase change. However, a large effective radius is usually required to ensure stable and precise discretization, increasing the computational cost. This study presents a new meshfree particle method called the compact moving particle semi-implicit (CMPS) method for incompressible free-surface and multiphase flows. In contrast to the existing particle methods, the first-order and second-order derivatives are discretized separately in the CMPS, enhancing the numerical stability significantly. By adopting a small effective radius, the CMPS can remarkably improve accuracy and reduce computational costs.

Oral presentation

System Identification and Ranking Table (SIRT) for chemical thermodynamics of severe accidents

Journeau, C.*; Bechta, S.*; Komlev, A.*; Kurata, Masaki; Ogi, Hiroshi; Matsumoto, Toshinori; Mohamad, A. B.; Barrachin, M.*; Quaini, A.*; Gu$'e$neau, C.*; et al.

no journal, , 

Oral presentation

Study on molten core coolability under precautionary water injection into containment vessel, 4; Improvement of jet breakup model in the JASMINE code

Matsumoto, Toshinori; Kawabe, Ryuhei; Sugiyama, Tomoyuki; Maruyama, Yu

no journal, , 

no abstracts in English

Oral presentation

Improvement of fuel-coolant interaction models for ex-vessel debris coolability evaluation

Matsumoto, Toshinori; Kawabe, Ryuhei; Sugiyama, Tomoyuki; Maruyama, Yu

no journal, , 

38 (Records 1-20 displayed on this page)