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Kosaka, Wataru; Uchibori, Akihiro; Okano, Yasushi; Yanagisawa, Hideki*
Proceedings of 20th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-20) (Internet), p.1150 - 1163, 2023/08
The leakage of pressurized water from a steam generator (SG) and the progress after that are a key issue in the safety assessment or design of a SG in sodium-cooled fast reactor. The analysis code LEAP-III can evaluate a rate of water leakage during the long-term event progress, i.e., from the self-wastage initiated by an occurrence of a microscopic crack in a tube wall to the water leak detection and water/water-vapor blowdown. Since LEAP-III consists of semi-empirical formulae and one-dimensional equations of conservation, it has an advantage in short computation time. Thus, LEAP-III can facilitate the exploration of various new SG designs in the development of innovative reactors. However, there are several problems, such as an excessive conservative result in some case and the need for numerous experiments or preliminary analyses to determine tuning parameters of models in LEAP-III. Hence, we have developed a Lagrangian particle method code, which is characterized by a simpler computational principle and faster calculation. In this study, we have improved the existing particle pair search method for interparticle interaction in this code and developed an alternative model without the pair search. Through the trial analysis simulating in a tube bundle system, it was confirmed that new models reduced the computation time. In addition, it was shown that representative temperatures of the heat-transfer tubes evaluated by this particle method code, which is used to predict the tube failure in LEAP-III, were good agreement with that by SERAPHIM, which is a detailed mechanistic analysis method code.
Kosaka, Wataru; Uchibori, Akihiro; Takata, Takashi; Yanagisawa, Hideki*; Watanabe, Akira*; Jang, S.*
Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 11 Pages, 2022/03
For the safety assessment of a steam generator (SG) in a sodium-cooled fast reactor, the analysis code LEAP-III can evaluate the water leak rate during the long-term event progress including the tube failure propagation triggered by an occurrence of a small water leak in a failed heat transfer tube in SG. The LEAP-III has the advantage in completing the calculation with low computational cost since it consists of semi-empirical formulae and one-dimensional equations of conservation. However, an evaluation model of temperature distribution by the reacting jet provides wider high temperature region than the experimental data. As a result, LEAP-III shows excessive conservativeness in some case. A Lagrangian particle method code based on engineering approaches has been developed in order to improve this model to get more realistic temperature distribution. In this method, the jet behavior and chemical reaction are simulated using Newton's equation of motion with several engineering approximations instead of solving multi-dimension multiphase thermal hydraulic equations with sodium-water reaction. In this study, interparticle interaction force model was added, and also the chemical reaction and gas-liquid heat transfer evaluation models were improved. We conducted a test analysis, and compared the results by this particle method with the ones by SERAPHIM, that is a mechanistic analysis code for multi-dimensional multiphase flow considering compressibility and sodium-water reaction. Through this test analysis, it confirmed that this particle method has the basic capability to get a realistic temperature distribution with low computational cost, and also to predict tube failure occurrence by coupled with LEAP-III.
Kosaka, Wataru; Uchibori, Akihiro; Yanagisawa, Hideki*; Takata, Takashi; Jang, S.*
Nihon Kikai Gakkai Rombunshu (Internet), 88(905), p.21-00310_1 - 21-00310_9, 2022/01
If a pressurized water/water-vapor leaks from a heat transfer tube in a steam generator (SG) in a sodium-cooled fast reactor (SFR), sodium-water reaction forms high-velocity, high-temperature, and corrosive jet. It would damage the other tubes and might propagate the tube failure in the SG. Thus, it is important to evaluate the effect of the tube failure propagation for safety assessment of SFR. The computational code LEAP-III can evaluate water leak rate during the tube failure propagation with short calculation time, since it consists of empirical formulae and one-dimensional equations of conservation. One of the empirical models, temperature distribution evaluation model, evaluates the temperature distribution in SG as circular arc isolines determined by experiments and preliminary analyses instead of complicated real distribution. In order to improve this model to get more realistic temperature distribution, we have developed the Lagrangian particle method based on engineering approaches. In this study, we have focused on evaluating gas flow in a tube bundle system, and constructed new models for the gas-particles behavior around a tube to evaluate void fraction distribution near the tube. Through the test analysis simulating one target tube system, we confirmed the capability of the models and next topic to improve the models.
Sr in cattle bone and tooth samples by inductively coupled plasma mass spectrometryKoarai, Kazuma; Matsueda, Makoto; Aoki, Jo; Yanagisawa, Kayo*; Terashima, Motoki; Fujiwara, Kenso; Kino, Yasushi*; Oka, Toshitaka; Takahashi, Atsushi*; Suzuki, Toshihiko*; et al.
Journal of Analytical Atomic Spectrometry, 36(8), p.1678 - 1682, 2021/08
Times Cited Count：5 Percentile：54.36(Chemistry, Analytical)Rapid analysis of Sr in bone and tooth samples of cattle were achieved by an inductively coupled plasma mass spectrometry (ICP-MS) coupled with mass shift and solid phase extraction techniques. Limit of detection (LOD) in the ICP-MS measurement of 0.1 g samples was lower than that of the radioactivity measurement. Analytical time of the ICP-MS method was reduced from 20 days to 11 hours, compared with the radiometric method. Therefore, the ICP-MS method can be rapid and useful procedure of Sr in small bone and tooth samples derived from terrestrial animals.
Kosaka, Wataru; Uchibori, Akihiro; Yanagisawa, Hideki*; Takata, Takashi; Jang, S.*
Proceedings of 28th International Conference on Nuclear Engineering (ICONE 28) (Internet), 6 Pages, 2021/08
For safety assessment or design of a steam generator (SG) of a sodium-cooled fast reactor, it is important to evaluate the effects of a multiphase flow involving sodium-water reaction. If pressurized water/water-vapor leaks from a tube, it forms a corrosive, high-temperature, and high-velocity jet, and may cause failure of the adjacent tubes. The occurrence of tube failure on many tubes will lead to failure of the boundary between the primary and secondary cooling loops. The numerical analysis code, LEAP-III, has been developed to evaluate water leak rate considering the effects of the above-mentioned phenomena with short computational time. In some cases, however, the current LEAP-III provides excessive conservativeness due to its temperature distribution evaluation model. In order to reduce this excess, we have developed a new Lagrange particle method with several engineering approaches. We also performed test analyses which simulate time development of the vapor jet with chemical reaction in a SG. The results of the developed method were compared with ones of the multi-dimensional multiphase thermal hydraulic analysis code, SERAPHIM which considers compressibility and chemical reaction. Through the test analyses, the basic capability of the developed method was confirmed.
Kosaka, Wataru; Uchibori, Akihiro; Yanagisawa, Hideki*; Takata, Takashi; Jang, S.*
Dai-25-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (Internet), 4 Pages, 2021/07
If a pressurized water/water-vapor leaks from a heat transfer tube in a steam generator (SG) in a sodium-cooled fast reactor (SFR), sodium-water reaction forms high-velocity, high-temperature, and corrosive jet. It would damage the other tubes and might propagate the tube failure in the SG. Thus, it is important to evaluate the effect of the tube failure propagation for safety assessment of SFR. The computational code LEAP-III can evaluate water leak rate during the tube failure propagation with short calculation time, since it consists of empirical formulae and one-dimensional equations of conservation. One of the empirical models, temperature distribution evaluation model, evaluates the temperature distribution in SG as circular arc isolines determined by experiments and preliminary analyses instead of complicated real distribution. In order to improve this model to get more realistic temperature distribution, we have developed the Lagrangian particle method based on engineering approaches. In this study, we have focused on evaluating gas flow in a tube bundle system, and constructed new models for the gas-particles behavior around a tube to evaluate void fraction distribution near the tube. Through the test analysis simulating one target tube system, we confirmed the capability of the models and next topic to improve the models.
Onoe, Hironori; Kosaka, Hiroshi*; Matsuoka, Toshiyuki; Komatsu, Tetsuya; Takeuchi, Ryuji; Iwatsuki, Teruki; Yasue, Kenichi
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 26(1), p.3 - 14, 2019/06
In this study, it is focused on topographic changes due to uplift and denudation, also climate perturbations, a method which is able to assess the long-term variability of groundwater flow conditions using the coefficient variation based on some steady-state groundwater flow simulation results was developed. Spatial distribution of long residence time area which is not much influenced due to long-term topographic change and recharge rate change during the past one million years was able to estimate through the case study of the Tono area, Central Japan. By applying this evaluation method, it is possible to identify the local area that has low variability of groundwater flow conditions due to topographic changes and climate perturbations from the regional area quantitatively and spatially.
Onoe, Hironori; Kosaka, Hiroshi*; Takeuchi, Ryuji; Saegusa, Hiromitsu
JAEA-Research 2015-008, 146 Pages, 2015/08
JAEA-Research-2015-008.pdf:76.46MB
Mizunami Underground Research Laboratory (MIU) Project is being carried out by Japan Atomic Energy Agency (JAEA) in the Cretaceous Toki granite in the Tono area, central Japan. The MIU Project has three overlapping phases: Surface-based Investigation (Phase I), Construction (Phase II) and Operation (Phase III). In this study, calibration of hydrogeological model and groundwater flow simulation using the data obtained by the Phase I and Phase II were carried out in order to develop the methodology for construction and update of hydrogeological model on Site Scale. As a result, hydrogeological model on Site Scale, which is able to simulate comprehensively the obtained data regarding groundwater pressure distribution before excavation of the MIU facilities, hydraulic responses and inflow volume during excavation of the MIU facilities, was constructed.
Kosaka, Hiroshi; Saegusa, Hiromitsu; Kurihara, Arata*; Onoe, Hironori
JAEA-Research 2012-012, 100 Pages, 2012/07
JAEA-Research-2012-012.pdf:17.95MB
In this study, groundwater flow and particle tracking simulations using hydrogeological models have been carried out in order to evaluate the relationship between understanding of groundwater flow characteristics and the amount of information that is increased by the progress of investigations. The influences of difference of the method for interpretation of hydrogeology have been also evaluated. As a result, uncertainties of the groundwater flow characteristics were decreased by increasing the amount of information. It was also found that the distribution of large-scale discrete features and the heterogeneity of groundwater flow characteristics affect the groundwater flow characteristics. Furthermore, the method to identify the target of further investigation and to make plan for the investigation were proposed.
Shimo, Michito*; Kumamoto, So*; Kosaka, Hiroshi; Onoe, Hironori; Saegusa, Hiromitsu; Mizuno, Takashi; Oyama, Takuya
JAEA-Research 2012-004, 126 Pages, 2012/04
JAEA-Research-2012-004.pdf:14.3MB
One of the goals of Mizunami Underground Research Laboratory (MIU) Project is to develop technical basis for investigation, analysis and evaluation technologies for understanding deep underground geological environment in various scales. Understanding groundwater flow system is one of the important issues in the project, and to achieve this purpose, technologies for a hydrogeological model and the groundwater flow simulation technique, have to be established. In this study, hydrogeological modeling and groundwater flow simulations have been carried out in order to predict hydraulic and geochemical impacts around the MIU Construction Site and inflow rate into the MIU facilities. As a result of this study, the significant hydrogeological structures could be estimated. The inflow rate into the MIU facilities and hydraulic and geochemical impacts with the MIU facilities construction could be predicted. The effect of pre-grouting to the MIU facilities could be also confirmed.
Kosaka, Hiroshi; Saegusa, Hiromitsu; Yasue, Kenichi; Kusano, Tomohiro; Onoe, Hironori
Proceedings of 19th International Conference on Nuclear Engineering (ICONE-19) (CD-ROM), 9 Pages, 2011/10
The methodology for estimation of the long-term evolution of groundwater flow conditions are being developed using approaches on the basis of deductive and inductive methods in the case of Tono area. Based on the studies using the approach on the basis of deductive method, it has been confirmed that the method combining physical modeling of topographic change and groundwater flow simulations is useful for estimating of changes in groundwater flow conditions in the future due to topographic and climatic perturbations. Existing information for estimation of surface hydrological conditions, which are to be used for assignment of boundary conditions for the groundwater flow simulation, has been gathered from many sources and reviewed based on modern-analogue methods. In the studies using the approach on the basis of inductive method, paleo-hydrogeological studies have been carried out on several spatial and time scales. Through the study on the largest spatial scale, a methodology needed to understand changes of groundwater flow conditions due to long-term topographic change is proposed to efficiently identify the area to be carried out site characterization involving field investigations. And then, information to estimate the paleo-topography and paleo-climate has been obtained from literature surveys and field investigations. Through these studies, it has been confirmed that these two approaches are useful for estimation of the long-term evolution of deep groundwater flow conditions.
Takeuchi, Ryuji; Kosaka, Hiroshi; Sato, Atsuya*; Tomiyama, Shingo*; Kageyama, Soichiro*; Ikeda, Makoto*
JAEA-Research 2011-008, 77 Pages, 2011/06
JAEA-Research-2011-008.pdf:4.76MB
Subsurface water balance observation is a kind of methods in order to estimate a recharge rate. Results of the observation are affected by the various factors such as the scale, the topography, a geological feature, the climate. Therefore, the observation in the regional scale is necessary at many basins. The purpose of this study is to confirm the applicability of the method for the evaluation of runoff volume, which is one of parameters to evaluate the recharge rate by surface water balance observation, by geomorphometry and statistical analyses using digital elevation model (DEM). The runoff index which is the original indicator to evaluate the degree of flow rate on a catchment was calculated by the comparison between the result of geomorphometry and statistics analyses, and the observed data of river flow rate in the monitoring stations. Using this index, the flow rate of the Hiyoshi River was evaluated. The evaluated flow rate was about 60% against the observed flow rate.
Kosaka, Hiroshi; Saegusa, Hiromitsu; Onoe, Hironori; Takeuchi, Ryuji
JAEA-Research 2010-037, 42 Pages, 2011/01
JAEA-Research-2010-037.pdf:16.27MB
Mizunami Underground Research Laboratory (MIU) Project is being carried out by Japan Atomic Energy Agency (JAEA) in the Cretaceous Toki granite in the Tono area, central Japan. The MIU project is a broad scientific study of the deep geological environment as a component of the research and development supporting geological disposal of high-level radioactive wastes. One of the main goals of the project is to establish techniques for comprehensive investigation, analysis and assessment of the deep geological environment in fractured crystalline rock. In this study, hydrogeological modeling and groundwater flow simulation taking into consideration the long-term pumping test has been carried out in order to reflect making test specifications of long-term pumping test. The pumping test will be carried out using the borehole, which will be drilled from underground research gallery in fiscal 2010. In this groundwater flow simulation, the sensitive analysis focused on location of pumping interval along the borehole, pumping time and pumping flow rate was conducted to predict the influence of these test specifications on the pressure response in pressure monitoring boreholes. As a result, the different variations of pressure response were indicated by the differences of the location of pumping interval bounded by the fault. In addition, small effect of difference of pumping time (2 weeks or 4 weeks) on pressure response was predicted. The recommendation of test specifications of long-term pumping test was made based on this study.
Takeuchi, Ryuji; Saegusa, Hiromitsu; Oyama, Takuya; Keya, Hiromichi; Sato, Atsuya; Kosaka, Hiroshi; Takeda, Masaki; Daimaru, Shuji; Takeuchi, Shinji
JAEA-Research 2010-018, 133 Pages, 2010/08
JAEA-Research-2010-018.pdf:28.5MB
The Mizunami Underground Laboratory Project is a comprehensive research project investigating the deep underground environment within crystalline rock. The project goals of the project from surface-based investigation phase (Phase I) through to operation phase (Phase III) are: to establish techniques for investigation, analysis and assessment of the deep geological environment, and to develop a range of engineering for deep underground application. Currently, the project is under the construction phase (Phase II). One of the Phase II goals, which is for the project goal, was set to develop and revise models of the geological environment using the investigation results obtained during excavation, and determine and assess changes in the geological environment in response to excavation. This document presents the overview of results of the research and development on "hydrogeology" performed in fiscal year 2008, with regard to the Phase II goal.
White, M. J.*; Guimer
, J.*; Oyama, Takuya; Kosaka, Hiroshi; Robinson, P.*; Saegusa, Hiromitsu
Proceedings of 12th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM '09/DECOM '09) (CD-ROM), 10 Pages, 2009/10
JAEA has been developing modelling techniques to overcome these problems as part of the Mizunami Underground Research Laboratory. An integrated geological and hydrogeological modelling, and visualization system referred to as GEOMASS has been developed, which allows for transient unsaturated groundwater flow modelling in the presence of dynamic underground excavation models. The flow simulator in GEOMASS, FracAffinity, allows for such modelling by the application of sophisticated gridding techniques, allowing for modification of hydraulic conductivity in key zones, and by suitable modification of water retention models. The approaches that have been developed in GEOMASS have been tested through a series of models of increasing complexity, and the testing has demonstrated that there is no significant impact on estimates of regional groundwater flows or local estimates of flow into underground excavations.
Onoe, Hironori; Sasao, Eiji; Saegusa, Hiromitsu; Kosaka, Hiroshi*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 8(1), p.40 - 53, 2009/03
It is important to understand how long-term geological phenomena influence deep hydrogeological and hydrochemical environments, and to predict influence of long-term geological phenomena in the future for the geological disposal of nuclear wastes. In this study, influence of long-term topographic change on deep groundwater flow conditions was numerically assessed using paleohydrogeological approach. Concretely, paleotopography of wide area was estimated in generalities and groundwater flow simulations were carried out in the Tono area. As a result, it was confirmed that the effects of long-term topography change and hydraulic features of faults on groundwater flow conditions. The methodology in order to understand change of groundwater flow conditions due to long-term topographic change efficiently for identification of detail investigation and assessment area is proposed based on the result of this study.
Saegusa, Hiromitsu; Onoe, Hironori; Kinoshita, Hirohisa*; Sasao, Eiji; Kosaka, Hiroshi*; Tokusu, Mitsuhiro*; Yoden, Toshiaki*
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Onoe, Hironori; Saegusa, Hiromitsu; Sasao, Eiji; Kinoshita, Hirohisa*; Kosaka, Hiroshi*
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Keya, Hiromichi; Takeuchi, Ryuji; Toya, Naruhisa; Sato, Atsuya; Saegusa, Hiromitsu; Oyama, Takuya; Kosaka, Hiroshi
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Kosaka, Hiroshi; Saegusa, Hiromitsu; Oyama, Takuya
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