The Experts below are selected from a list of 192 Experts worldwide ranked by ideXlab platform
Isao Aoki - One of the best experts on this subject based on the ideXlab platform.
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Plasma shutdown system for fusion Experimental Reactors
Fusion Technology, 1997Co-Authors: Takashi Okazaki, Yasushi Seki, Takuro Honda, Tomoaki Kunugi, Isao AokiAbstract:The concept for a plasma shutdown system has been studied for fusion Experimental Reactors. An impurity pellet injection system is proposed as the plasma shutdown system. The density limit disruption is employed by using impurity pellet injection. The pellet size and its injection velocity are obtained with an evaluation model of the tearing mode and a model of pellet ablation. The main functions of the impurity pellet injection system are checked by the trial manufacturer. The concept for this plasma shutdown system is extended to the International Thermonuclear Experimental Reactor (ITER).
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Dust removal system for fusion Experimental Reactors
Proceedings of 16th International Symposium on Fusion Engineering, 1995Co-Authors: M. Onozuka, Y. Ueda, K. Takahashi, Y. Seki, S. Ueda, Isao AokiAbstract:Development of a dust removal system using static electricity has been conducted. It is envisioned that the system can collect and transport dust under vacuum. In the system, the dust is charged by dielectric polarization and floated by an electrostatic attraction force that is generated by the DC electric field. The dust is then transported by the electric curtain formed by the three-phase AC electric field. Experimental investigation has been conducted to examine the characteristics of the system. Current research results indicate that the dust removal system using static electricity can be used for fusion Experimental Reactors.
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Concept of plasma shutdown system for fusion Experimental Reactors
17th IEEE NPSS Symposium Fusion Engineering (Cat. No.97CH36131), 1Co-Authors: Takashi Okazaki, Yasushi Seki, Takuro Honda, K. Teruyama, Tomoaki Kunugi, Isao Aoki, R. Yoshino, H. HiratsukaAbstract:The concept for a plasma shutdown system has been studied for fusion Experimental Reactors. An impurity pellet injection system was proposed as the plasma shutdown system. The density limit disruption is employed by using impurity pellet injection. The main principal functions of the impurity pellet injection system were checked after its trial manufacture.
Yasushi Seki - One of the best experts on this subject based on the ideXlab platform.
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Plasma shutdown system for fusion Experimental Reactors
Fusion Technology, 1997Co-Authors: Takashi Okazaki, Yasushi Seki, Takuro Honda, Tomoaki Kunugi, Isao AokiAbstract:The concept for a plasma shutdown system has been studied for fusion Experimental Reactors. An impurity pellet injection system is proposed as the plasma shutdown system. The density limit disruption is employed by using impurity pellet injection. The pellet size and its injection velocity are obtained with an evaluation model of the tearing mode and a model of pellet ablation. The main functions of the impurity pellet injection system are checked by the trial manufacturer. The concept for this plasma shutdown system is extended to the International Thermonuclear Experimental Reactor (ITER).
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Shielding Analysis for Toroidal Field Coils Around Exhaust Duct in Fusion Experimental Reactors
Fusion Technology, 1996Co-Authors: S. Sato, Hideyuki Takatsu, Koichi Maki, Yasushi SekiAbstract:Shielding analyses for toroidal field coils (TFCs) around the exhaust duct in a nuclear fusion Experimental reactor have been performed by two-dimensional discrete ordinate method, and their peak nuclear responses were evaluated. From the results, it was found that the duct wall of about 410 mm thickness was required in case of no shield structure behind the divertor in order to satisfy the radiation limits of TFCs. Taking overestimation due to the analysis model simulating the exhaust duct with a toroidally continuous opening into account, nuclear responses may possibly be lower than the radiation limits by 300 mm thick duct wall. By providing a 480 mm thick shield with 140 mm wide slits behind the divertor, nuclear responses were reduced to about 1/20, and they were equal to or lower than the radiation limits for 200 mm thick duct wall. Also, taking overestimation, nuclear responses may possibly be more than six times lower than the radiation limits for 200 mm thick duct wall. 5 refs., 7 figs., 4 tabs.
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Primary research and development needs for fusion Experimental Reactors: Perspectives
Fusion Engineering and Design, 1991Co-Authors: Kiyoshi Shibanuma, Hideyuki Takatsu, Eisuke Tada, Yasushi Seki, Yoshihiro Ohara, Shinzaburo Matsuda, Hiroshi Tsuji, Haruyuki Kimura, Shun-ichi Tanaka, Hiroshi YoshidaAbstract:Abstract The time has come for fusion Experimental reactor programmes (ITER/FER) to enter the engineering design phase, where the large scale models which are capable of extrapolation to the construction of Reactors will be developed as the core of the main activities. A brief review of the present status of the required R&D for Experimental Reactors, and the technological realization perspectives, are described.
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Concept of plasma shutdown system for fusion Experimental Reactors
17th IEEE NPSS Symposium Fusion Engineering (Cat. No.97CH36131), 1Co-Authors: Takashi Okazaki, Yasushi Seki, Takuro Honda, K. Teruyama, Tomoaki Kunugi, Isao Aoki, R. Yoshino, H. HiratsukaAbstract:The concept for a plasma shutdown system has been studied for fusion Experimental Reactors. An impurity pellet injection system was proposed as the plasma shutdown system. The density limit disruption is employed by using impurity pellet injection. The main principal functions of the impurity pellet injection system were checked after its trial manufacture.
C. Bernaudat - One of the best experts on this subject based on the ideXlab platform.
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Simulation of reactivity-initiated accident transients on UO2 -M5® fuel rods with ALCYONE V1.4 fuel performance code
Nuclear Engineering and Technology, 2018Co-Authors: I. Guenot-delahaie, J. Sercombe, T. Helfer, P. Goldbronn, E. Federici, A. Parrot, C. Delafoy, T Le Jolu, C. BernaudatAbstract:The ALCYONE multidimensional fuel performance code codeveloped by the CEA, EDF, and AREVA NP within the PLEIADES software environment models the behavior of fuel rods during irradiation in commercial pressurized water Reactors (PWRs), power ramps in Experimental Reactors, or accidental conditions such as loss of coolant accidents or reactivity-initiated accidents (RIAs). As regards the latter case of transient in particular, ALCYONE is intended to predictively simulate the response of a fuel rod by taking account of mechanisms in a way that models the physics as closely as possible, encompassing all possible stages of the transient as well as various fuel/cladding material types and irradiation conditions of interest. On the way to complying with these objectives, ALCYONE development and validation shall include tests on PWR-UO 2 fuel rods with advanced claddings such as M5® under " low pressureelow temperature " or " high pressureehigh temperature " water coolant conditions. This article first presents ALCYONE V1.4 RIA-related features and modeling. It especially focuses on recent developments dedicated on the one hand to nonsteady water heat and mass transport and on the other hand to the modeling of grain boundary cracking-induced fission gas release and swelling. This article then compares some simulations of RIA transients performed on UO 2-M5® fuel rods in flowing sodium or stagnant water coolant conditions to the relevant Experimental results gained from tests performed in either the French CABRI or the Japanese NSRR nuclear transient reactor facilities. It shows in particular to what extent ALCYONEdstarting from base irradiation conditions it itself computesdis currently able to handle both the first stage of the transient, namely the pellet-cladding mechanical interaction phase, and the second stage of the transient, should a boiling crisis occur. Areas of improvement are finally discussed with a view to simulating and analyzing further tests to be performed under prototypical PWR conditions within the CABRI International Program. M5® is a trademark or a registered trademark of AREVA NP in the USA or other countries.
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simulation of ria transients on uo2-m5 fuel rodswith alcyone v1.4 fuel performance code
2017Co-Authors: I. Guenot-delahaie, J. Sercombe, T. Helfer, P. Goldbronn, E. Federici, T. Lejolu, A. Parrot, C. Delafoy, C. BernaudatAbstract:The ALCYONE multidimensional fuel performance code co-developed by the CEA, EDF and AREVA NPwithin the PLEIADES software environment models the behavior of fuel rods during irradiation incommercial Pressurized Water Reactors (PWRs), power ramps in Experimental Reactors or accidentalconditions such as Loss Of Coolant Accidents (LOCAs) or Reactivity-Initiated Accidents (RIAs). Asregards the latter case of transient in particular, ALCYONE is intended to predictively simulate theresponse of a fuel rod by taking account of mechanisms as close to physics as possible, encompassingall possible stages of the transient as well as various fuel/cladding material types and irradiationconditions of interest. On the way to complying with these objectives, its development and validationshall include tests on PWR-UO2 fuel rods with advanced claddings such as M5 under low pressurelowtemperature or high pressure-high temperature water coolant conditions.This paper first presents the ALCYONE V1.4 RIA-related features and modeling. It especially focuses onrecent developments dedicated on the one hand to non steady water heat and mass transport and onthe other hand to the modeling of grain-boundary cracking-induced fission gas release and swelling.This paper then compares some simulations of RIA transients performed on UO2-M5 fuel rods inflowing sodium or stagnant water coolant conditions to the relevant Experimental results gained fromtests performed in either the French CABRI or the Japanese NSRR nuclear transient reactor facilities. Itshows in particular to what extent ALCYONE starting from base irradiation conditions it itselfcomputes is currently able to handle both the first stage of the transient, namely the Pellet CladdingMechanical Interaction (PCMI) phase, and the second stage of the transient, should the boiling crisisoccur.Areas of improvement are finally discussed with a view to simulating and analyzing further tests to beperformed under prototypical PWR conditions within the CABRI International Program.
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SIMULATION OF RIA TRANSIENTS ON UO2 -M5® FUEL RODS WITH ALCYONE V1.4 FUEL PERFORMANCE CODE
2017Co-Authors: I. Guenot-delahaie, J. Sercombe, T. Helfer, P. Goldbronn, E. Federici, A. Parrot, C. Delafoy, T Le Jolu, C. BernaudatAbstract:The ALCYONE multidimensional fuel performance code co-developed by the CEA, EDF and AREVA NP within the PLEIADES software environment models the behavior of fuel rods during irradiation in commercial Pressurized Water Reactors (PWRs), power ramps in Experimental Reactors or accidental conditions such as Loss Of Coolant Accidents (LOCAs) or Reactivity-Initiated Accidents (RIAs). As regards the latter case of transient in particular, ALCYONE is intended to predictively simulate the response of a fuel rod by taking account of mechanisms as close to physics as possible, encompassing all possible stages of the transient as well as various fuel/cladding material types and irradiation conditions of interest. On the way to complying with these objectives, its development and validation shall include tests on PWR-UO 2 fuel rods with advanced claddings such as M5® under " low pressure-low temperature " or " high pressure-high temperature " water coolant conditions. This paper first presents the ALCYONE V1.4 RIA-related features and modeling. It especially focuses on recent developments dedicated on the one hand to non steady water heat and mass transport and on the other hand to the modeling of grain boundary cracking-induced fission gas release and swelling. This paper then compares some simulations of RIA transients performed on UO 2-M5® fuel rods in flowing sodium or stagnant water coolant conditions to the relevant Experimental results gained from tests performed in either the French CABRI or the Japanese NSRR nuclear transient reactor facilities. It shows in particular to what extent ALCYONE – starting from base irradiation conditions it itself computes – is currently able to handle both the first stage of the transient, namely the Pellet Cladding Mechanical Interaction (PCMI) phase, and the second stage of the transient, should the boiling crisis occur. Areas of improvement are finally discussed with a view to simulating and analyzing further tests to be performed under prototypical PWR conditions within the CABRI International Program. M5® is a trademark or a registered trademark of AREVA NP in the USA or other countries.
Swee Loong Khor - One of the best experts on this subject based on the ideXlab platform.
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Effects of hydraulic retention time on behavior of start-up submerged membrane bioreactor with prolonged sludge retention time
Desalination, 2006Co-Authors: Darren Delai Sun, Choon Teck Hay, Swee Loong KhorAbstract:Abstract High strength synthetic wastewater was treated using submerged ceramic membrane bioReactors (MBRs) at sludge retention time (SRT) of 200 d. It was found that the MBRs could achieve both COD and TOC overall removal efficiency at 96% in all the 3 Experimental Reactors. The MBRs could also be operated at higher solids concentration of up to 20 g/l. The sludge concentration, which was inversely proportional to the hydraulic retention time (HRT), yielded excellent nutrient removal and low F/M ratio and high sludge age conditions. The particle size of sludge was found to decline and eventually attained a constant mean size of approximately 50 μm. This led to an intriguing discovery that aeration at 8 l/min was the underlying factor contributing to the decline in the mean size of sludge particles. It was also found that the particle size of sludge played an influential role on the specific permeate flux rate. Small particles like soluble organic particles would deteriorate the permeability of the ceramic membrane by directly absorbing into the 0.2 μm pores. An improvement in the flux rate was observed when sludge floc breakage occurred and thus bringing down the mean sludge particle size. These observations brought along the conclusion that aeration was a significant parameter governing both the size of the sludge floc and the filtration performance.
Takashi Okazaki - One of the best experts on this subject based on the ideXlab platform.
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Plasma shutdown system for fusion Experimental Reactors
Fusion Technology, 1997Co-Authors: Takashi Okazaki, Yasushi Seki, Takuro Honda, Tomoaki Kunugi, Isao AokiAbstract:The concept for a plasma shutdown system has been studied for fusion Experimental Reactors. An impurity pellet injection system is proposed as the plasma shutdown system. The density limit disruption is employed by using impurity pellet injection. The pellet size and its injection velocity are obtained with an evaluation model of the tearing mode and a model of pellet ablation. The main functions of the impurity pellet injection system are checked by the trial manufacturer. The concept for this plasma shutdown system is extended to the International Thermonuclear Experimental Reactor (ITER).
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Concept of plasma shutdown system for fusion Experimental Reactors
17th IEEE NPSS Symposium Fusion Engineering (Cat. No.97CH36131), 1Co-Authors: Takashi Okazaki, Yasushi Seki, Takuro Honda, K. Teruyama, Tomoaki Kunugi, Isao Aoki, R. Yoshino, H. HiratsukaAbstract:The concept for a plasma shutdown system has been studied for fusion Experimental Reactors. An impurity pellet injection system was proposed as the plasma shutdown system. The density limit disruption is employed by using impurity pellet injection. The main principal functions of the impurity pellet injection system were checked after its trial manufacture.
