CFD analysis on stratification dissolution and breakup of the air-helium gas mixture by natural convection in a large-scale enclosed vessel

Hamdani, A.; Abe, Satoshi; Ishigaki, Masahiro; Shibamoto, Yasuteru; Yonomoto, Taisuke

Progress in Nuclear Energy, 153, p.104415_1 - 104415_16, 2022/11

https://doi.org/10.1016/j.pnucene.2022.104415

Experimental investigation of natural convection and gas mixing behaviors driven by outer surface cooling with and without density stratification consisting of an air-helium gas mixture in a large-scale enclosed vessel

Abe, Satoshi; Hamdani, A.; Ishigaki, Masahiro*; Shibamoto, Yasuteru

Annals of Nuclear Energy, 166, p.108791_1 - 108791_18, 2022/02

https://doi.org/10.1016/j.anucene.2021.108791

Development of remote sensing technique using radiation resistant optical fibers under high-radiation environment

Ito, Chikara; Naito, Hiroyuki; Ishikawa, Takashi; Ito, Keisuke; Wakaida, Ikuo

JPS Conference Proceedings (Internet), 24, p.011038_1 - 011038_6, 2019/01

https://doi.org/10.7566/JPSCP.24.011038

A high-radiation resistant optical fiber has been developed in order to investigate the interiors of the reactor pressure vessels and the primary containment vessels at the Fukushima Daiichi Nuclear Power Station. The tentative dose rate in the reactor pressure vessels is assumed to be up to 1 kGy/h. We developed a radiation resistant optical fiber consisting of a 1000 ppm hydroxyl doped pure silica core and 4 % fluorine doped pure silica cladding. We attempted to apply the optical fiber to remote imaging technique by means of fiberscope. The number of core image fibers was increased from 2000 to 22000 for practical use. The transmissive rate of infrared images was not affected after irradiation of 1 MGy. No change in the spatial resolution of the view scope by means of image fiber was noted between pre- and post-irradiation. We confirmed the applicability of the probing system, which consists of a view scope using radiation-resistant optical fibers.

Stratification breakup by a diffuse buoyant jet; The MISTRA HM1-1 and 1-1bis experiments and their CFD analysis

Abe, Satoshi; Studer, E.*; Ishigaki, Masahiro; Shibamoto, Yasuteru; Yonomoto, Taisuke

Nuclear Engineering and Design, 331, p.162 - 175, 2018/05

https://doi.org/10.1016/j.nucengdes.2018.01.050

Verification of alternative dew point hygrometer for CV-LRT in MONJU; Short- and long-term verification for capacitance-type dew point hygrometer (Translated document)

Ichikawa, Shoichi; Chiba, Yusuke; Ono, Fumiyasu; Hatori, Masakazu; Kobayashi, Takanori; Uekura, Ryoichi; Hashiri, Nobuo*; Inuzuka, Taisuke*; Kitano, Hiroshi*; Abe, Hisashi*

JAEA-Research 2017-001, 40 Pages, 2017/03

JAEA-Research-2017-001.pdf:5.19MB

In order to reduce the influence on a plant schedule of the MONJU by the maintenance of dew point hygrometers, The JAEA examined a capacitance type dew point hygrometer as an alternative dew point hygrometer for a lithium-chloride type dew point hygrometer which had been used at the CV-LRT in the MONJU. As a result of comparing a capacitance type dew point hygrometer with a lithium-chloride type dew point hygrometer at the CV-LRT (Atmosphere: nitrogen, Testing time: 24 hours), there weren't significant difference between a capacitance type dew point hygrometer and a lithium-chloride type dew point hygrometer. As a result of comparing a capacitance dew point hygrometer with a high-mirror-surface type dew point hygrometer for long term verification (Atmosphere: air, Testing time: 24 months), the JAEA confirmed that a capacitance type dew point hygrometer satisfied the instrument specification (2.04C) required by the JEAC4203-2008.

Thermal-hydraulic safety research on nuclear containment vessel at JAEA

Shibamoto, Yasuteru; Yonomoto, Taisuke; Hotta, Akitoshi*

Nihon Genshiryoku Gakkai-Shi ATOMO, 58(9), p.553 - 557, 2016/09

no abstracts in English

A Study on improvement of RANS analysis for erosion of density stratified layer of multicomponent gas by buoyant jet in a containment vessel

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

Journal of Energy and Power Engineering, 9(7), p.599 - 607, 2015/07

https://doi.org/10.17265/1934-8975/2015.07.001

The analysis on a density stratification layer consisting of multiple gases in the reactor containment vessel is important for the safety assessment of sever accidents. The Japan Atomic Energy Agency (JAEA) has started the project on the containment thermal hydraulics. We carried out Computational Fluid Dynamics (CFD) analyses in order to investigate the erosion of the density stratification layer by a vertical buoyant jet under this project. We used the Reynolds averaged numerical simulation (RANS) and Large eddy simulation (LES) models to analyze the erosion of a density stratification layer by a vertical buoyant jet in a small vessel which represents a containment vessel. This numerical study calculates the turbulent mixing of a two-component (air and helium) gas mixture. The turbulence models used for the RANS analyses are two types of k- models. The first model is the low Reynolds number k- model developed by Launder and Sharma. The second model is modified from the first model in order to accurately consider the turbulent production and damping in a stratification layer. The results indicated while the erosion rate calculated by the low-Re k- model was much faster than that of the LES model, the modified k- model could calculate the erosion rate similar to the LES result.

Performance tests of reactor containment structures of the HTTR

Iigaki, Kazuhiko; Sakaba, Nariaki; Kawaji, Satoshi; Iyoku, Tatsuo

Transactions of 16th International Conference on Structural Mechanics in Reactor Technology (SMiRT-16) (CD-ROM), 7 Pages, 2001/08

no abstracts in English

Dynamic response of a containment surrounding extreme pressure source due to steam explosion

*; *; Maruyama, Yu; Yamano, N.; Sugimoto, Jun

Transactions of 13th International Conference on Structural Mechanics in Reactor Technology (SMiRT-13), 4, p.359 - 370, 1995/00

no abstracts in English

Experimental study of aerosol reentrainment from flashing pool in ALPHA program

Kudo, Tamotsu; Yamano, N.; Moriyama, Kiyofumi; Maruyama, Yu; Sugimoto, Jun

3rd Int. Conf. on Containment Design and Operation,Conf. Proc., Vol. 1, 0, 10 Pages, 1994/00

no abstracts in English