Possible criticality scenario and its mechanism of the Windscale Works criticality accident in 1970 analyzed by computational fluid dynamics and Monte Carlo neutron transport

Fukuda, Kodai

Annals of Nuclear Energy, 208(1), p.110748_1 - 110748_10, 2024/12

https://doi.org/10.1016/j.anucene.2024.110748

Preliminary combustion analyses using OpenFOAM

Thwe Thwe, A.; Terada, Atsuhiko; Hino, Ryutaro

JAEA-Technology 2018-012, 45 Pages, 2019/01

JAEA-Technology-2018-012.pdf:4.34MB

Under long-term storage of nuclear wastes including low- and high-level wastes, hydrogen can be spontaneously generated from corrosion of metal wastes and container wall itself, and from radiolysis of water in the waste. For the sake of hydrogen safety and the risk reduction of environmental contamination, we have started to investigate the behavior and characteristics of hydrogen combustion and explosion in waste vessel. In this report, we performed numerical simulation to investigate the characteristics of methane combustion by applying OpenFOAM. For combustion scenario, FireFoam solver with LES frame was used. As the results, the average temperature increased when the container height and inlet size increased. The simulation of gas diffusion by FireFoam results showed that helium diffused faster than hydrogen and methane. By XiFoame solver, the simulation was performed to obtain flame propagation radius for hydrogen-air premixed flame.

Influence of mesh non-orthogonality on numerical simulation of buoyant jet flows

Ishigaki, Masahiro; Abe, Satoshi; Shibamoto, Yasuteru; Yonomoto, Taisuke

Nuclear Engineering and Design, 314, p.326 - 337, 2017/04

AA2016-0575.pdf:1.57MB

https://doi.org/10.1016/j.nucengdes.2017.02.010

no abstracts in English

Approach to analysis of hydrogen combustion inside of radioactive waste vessels using CFD softwares based on an open source "OpenFOAM"

Thwe Thwe, A.; Terada, Atsuhiko; Hino, Ryutaro

no journal, , 

Since hydrogen is continuously generated and releases inside of high-level radioactive waste vessels, the awareness must be taken on the risk of hydrogen combustion and explosion. In hydrogen safety management, besides the experimental investigations, CFD approaches in predictions of flame propagation phenomena are of important role. As an approach to analysis of hydrogen combustion inside of vessels, we used the open source software, OpenFOAM and performed the simulations for propagation of H-air premixed flame. A new laminar flame speed model deduced from H-air explosion experiments by T. Katsumi et al. [Nagaoka Univ. Tech.] was implemented in the XiFoam solver and reproduced the propagation of H-air flame. Flame radius obtained by simulation agreed with the experimental results within 0.005s. Wrinkle flame formation was observed when the flame propagated outwardly as in experiments.