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Kato, Yukitaka*; Yamano, Hidemasa
Dai-28-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (Internet), 5 Pages, 2024/06
The research committee of energy storage technologies toward carbon neutrality developed four suggestions: 1) Development of energy storage best mix, 2) Transformation to green society, 3) utilization of heat storage technologies, and 4) Development of energy storage strategy beyond 2050. This paper describes suggestion 1) Development of energy storage best mix in response to large-scale deployments of variable renewable energy.
Kato, Yukitaka*; Yamano, Hidemasa
Dai-28-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (Internet), 5 Pages, 2024/06
The research committee of energy storage technologies toward carbon neutrality developed four suggestions: 1) Development of energy storage best mix, 2) Transformation to green society, 3) utilization of heat storage technologies, and 4) Development of energy storage strategy beyond 2050. This paper describes suggestion 2) Transformation to green society by zero-carbon energy, 3) further utilization of heat storage technologies in the industry and civil sectors, and 4) Development of energy storage strategy toward achievement of carbon negative emission beyond 2050.
Sato, Hiroyuki; Yan, X.; Tachibana, Yukio; Kunitomi, Kazuhiko; Kato, Yukitaka*
Nuclear Technology, 185(3), p.227 - 238, 2014/03
Times Cited Count：2 Percentile：15.22(Nuclear Science & Technology)Transient response of HTGR to DLOFC combined with failure of all reactor trip systems is analyzed. The characteristic behavior of the reactor during the long-term conduction cooldown event is found to be shaped by several parameters that are usually not considered in the safety design of the HTGR. For example, the reactivity coefficient of temperature of the graphite moderator is found to be a critical parameter to determining the final settling temperature of the fuel. Furthermore, this study finds that the peak fuel temperature reached during this event is correlated strongly even to the initial core operating temperatures prior to the initiation of the transient event. These and other results of this study are expected to provide useful input to the development of enhanced safety design guidelines for commercial HTGR reactor in the aftermath of the Fukushima accident.
Sato, Hiroyuki; Yan, X.; Tachibana, Yukio; Kato, Yukitaka*
Annals of Nuclear Energy, 49, p.33 - 40, 2012/11
Times Cited Count：16 Percentile：73.09(Nuclear Science & Technology)JP, 2010-199218
Licensable Patent Information Database 
Patent publication (In Japanese)
A control system design for the GTHTR300C is designed to follow significant seasonal variations of electric load demand. It combines inventory control used to adjust primary coolant pressure, flow bypass control used to regulate the coolant flow rate and turbine inlet temperature, and additional flow control to vary the IHX heat rate. The goal of the control system design is such that the wide range of load-following capability can be performed at constant reactor power and thermal efficiency, which maximizes plant economics, while minimizing transient thermal stresses in the reactor equipment. The original control system design shows that load-following operation at constant reactor power and thermal efficiency it to be feasible to allow peak electricity generation by a VHTR power and heat cogeneration system is feasible at constant reactor power and thermal efficiency.
Sato, Hiroyuki; Yan, X.; Tachibana, Yukio; Kato, Yukitaka*
International Journal of Gas Turbine, Propulsion and Power Systems (Internet), 4(3), p.17 - 24, 2012/10
JP, 2010-199218Licensable Patent Information Database Patent publication (In Japanese)
This paper presents an original control system design that enables electrical load-following with GTHTR300C, a nuclear gas turbine cogeneration plant. The control system is designed to follow daily electric load by taking advantage of the unique operation characteristics of the nuclear reactor and closed cycle gas turbine and the direct interface of the nuclear heat source and gas turbine engine. Control simulation of the overall plant system to follow daily load changes representative of developing countries are performed in order to demonstrate a technical feasibility of the system. The simulations results show that the load-follow can be effectively carried out by monitoring these parameters and controlling them with suitable control apparatus.
Sato, Hiroyuki; Yan, X.; Tachibana, Yukio; Kato, Yukitaka*
Proceedings of International Gas Turbine Congress 2011 (IGTC '11) (USB Flash Drive), 8 Pages, 2011/11
This paper presents an original control system design that enables electrical load-following with GTHTR300C, a nuclear gas turbine cogeneration plant. The control system is designed to follow daily electric load by taking advantage of the unique operation characteristics of the nuclear reactor and closed cycle gas turbine and the direct interface of the nuclear heat source and gas turbine engine. Control simulation of the overall plant system to follow daily load changes representative of developing countries are performed in order to demonstrate a technical feasibility of the system. The simulations results show that the load-follow can be effectively carried out by monitoring these parameters and controlling them with suitable control apparatus.
Sato, Hiroyuki; Kubo, Shinji; Yan, X.; Tachibana, Yukio; Kato, Yukitaka*
Progress in Nuclear Energy, 53(7), p.1009 - 1016, 2011/09
Times Cited Count：11 Percentile：61.73(Nuclear Science & Technology)Operability of Very High Temperature Reactor hydrogen cogeneration systems in response to abnormal transients initiated by the hydrogen production plant is one of the important concerns from economical and safety points of views. In the present study, basic controls and their integration for the GTHTR300C against abnormal transients of IS hydrogen production plant are presented. Transient simulations for selected load change events in the IS hydrogen production plants are performed by an original system analysis code which enables to evaluate major phenomena assumed in process heat exchangers of the IS hydrogen production plant. It is shown that abnormal load change events are successfully simulated by the system analysis code developed. The results demonstrated the efficacy technical feasibility of proposed controls for continuous operation of the reactor and power conversion unit against load change events in the IS hydrogen production plant.
Noguchi, Hiroki; Ishii, Katsunori; Ono, Masato; Sato, Hiroyuki; Sakaba, Nariaki; Kato, Yukitaka*
no journal, ,
Achieving decarbonization of iron industry, large amount of hydrogen is required for a hydrogen reduction ironmaking as a reduction material. In addition, high temperature heat must be supplied from the outside in order to prevent a shaft furnace temperature from decreasing due to an endothermic reaction of hydrogen reduction. Therefore, hydrogen heated up to high temperature by electricity or burning hydrogen is supplied to the shaft furnace. High temperature gas-cooled reactor (HTGR) can produce a large amount of hydrogen due to high temperature heat supply capability. Additionally high temperature generated from HTGR can be used for heating hydrogen. This presentation will introduce the high temperature hydrogen supply system using HTGR for contributing to decarbonization of ironmaking.
Sato, Hiroyuki; Kubo, Shinji; Yan, X.; Tachibana, Yukio; Kato, Yukitaka*
no journal, ,
One of the key areas to be investigated in VHTR co-generation system is an operability during transients initiated by the abnormal events by the hydrogen production plant since a continuous reactor operation and electricity generation is required in case of abnormal events in the hydrogen production plant from the economical point of view. In this study, control strategies are proposed and investigated against the transients initiated in the hydrogen production plant. Various transients were evaluated using the newly developed dynamic simulation code based on the RELAP5. The simulation results showed that the reactor could operate continuously during the transients of hydrogen production plant employing the proposed control strategy. In addition, the advantages of combining several control strategies are discussed comparing to the single application.