Noguchi, Hiroki; Takegami, Hiroaki; Kamiji, Yu; Tanaka, Nobuyuki; Iwatsuki, Jin; Kasahara, Seiji; Kubo, Shinji
International Journal of Hydrogen Energy, 44(25), p.12583 - 12592, 2019/05
JAEA has been conducting R&D on thermochemical water-splitting hydrogen production IS process to develop one of heat applications of high-temperature gas-cooled reactor. A test facility was constructed using corrosion-resistant industrial materials to verify integrity of the IS process components and to demonstrate continuous and stable hydrogen production. The performance of components installed in each section was confirmed. Subsequently, a trial operation of integration of the processing sections was successfully carried out for 8 hours with hydrogen production rate of approximately 10 NL/h. After that, hydrogen production operation was extended to 31 hours (approximately hydrogen production rate of 20 NL/h) by introducing a corrosion-resistance pump system with a developed shaft seal technology.
Dipu, A. L.; Ohashi, Hirofumi; Hamamoto, Shimpei; Sato, Hiroyuki; Nishihara, Tetsuo
Annals of Nuclear Energy, 88, p.126 - 134, 2016/02
The tritium concentration in the high temperature engineering test reactor (HTTR) was measured during the high temperature continuous operation for 50 days. The tritium concentration in the primary helium gas increased after startup and reached a maximum value. It then decreased slightly over the course during the normal operation phase. Decrease of concentration of tritium in primary helium gas during the normal operation phase could be attributed to the effect of tritium chemisorption on graphite. The tritium concentration in the secondary helium gas showed a peak value during the power ramp up phase. Afterwards, it decreased gradually at the end of normal power operation. It was assessed that the concentration and total quantity of tritium in the secondary helium cooling system for the HTTR-Iodine Sulfur (IS) system can be maintained below the regulatory limits, which means the hydrogen production plant can be exempt from the safety function of the nuclear facility.
Inaba, Yoshitomo; Nishihara, Tetsuo
JAERI-Tech 2005-033, 206 Pages, 2005/07
In this report, we investigated the effects of jet for the dispersion and explosion analysis of leaked gas, obstacles, position of an ignition point and cell size for the gas explosion analysis, and atmospheric stability for the dispersion analysis of the leaked gas, with PHOENICS, AutoReaGas, and AUTODYN. Then, we carried out two accident analyses about combustible fluid leakage based on the investigation results of these effects. As a result, it was shown that important buildings related to safety was hardly affected by the explosion of the leaked gas.
Hayashi, Koji; Inagaki, Yoshiyuki; Kato, Michio; Fujisaki, Katsuo*; Aita, Hideki; Takeda, Tetsuaki; Nishihara, Tetsuo; Inaba, Yoshitomo; Ohashi, Hirofumi; Katanishi, Shoji; et al.
JAERI-Tech 2005-032, 46 Pages, 2005/06
This is annual report on the experimental operation of the mock-up test facility with a full-scale reaction tube for the HTTR hydrogen production system in 2001 fiscal year. The first experimental operation was performed during two weeks from March 1, 2002 to March 13, 2002 to test on the thermal hydraulic performance of the steam reformer and also to train the operators. The thermal hydraulic performance test of the steam reformer was performed to evaluate the heat transfer characteristics between helium gas and process gas in the steam reformer. This report is summarized with an overview of the test, the results and its operation records.
Sakaki, Akihiro*; Kato, Michio; Hayashi, Koji; Fujisaki, Katsuo*; Aita, Hideki; Ohashi, Hirofumi; Takada, Shoji; Shimizu, Akira; Morisaki, Norihiro; Maeda, Yukimasa; et al.
JAERI-Tech 2005-023, 72 Pages, 2005/04
In order to establish the system integration technology to connect a hydrogen production system to a high temperature gas cooled reactor, the mock-up test facility with a full-scale reaction tube for the steam reforming HTTR hydrogen production system was constructed in fiscal year 2001 and its functional test operation was performed in the year. Seven experimental test operations were performed from fiscal year 2001 to 2004. On a period of each test operation, there happened some troubles. For each trouble, the cause was investigated and the countermeasures and the improvement works were performed to succeed the experiments. The tests were successfully achieved according to plan.This report describes the improvement works on the test facility performed from fiscal year 2001 to 2004.
Sato, Hiroyuki; Ohashi, Hirofumi; Inaba, Yoshitomo; Maeda, Yukimasa; Takeda, Tetsuaki; Nishihara, Tetsuo; Inagaki, Yoshiyuki
JAERI-Tech 2005-014, 89 Pages, 2005/03
In a hydrogen production system using HTTR, it is required to control a secondary helium gas temperature within an allowable value at an intermediate heat exchanger (IHX) inlet to prevent a reactor scram. To mitigate thermal disturbance of the secondary helium gas caused by the hydrogen production system, a cooling system of the secondary helium gas using a steam generator(SG) and a radiator will be installed at the downstream of the chemical reactor. In order to verify a numerical analysis code of the cooling system, numerical analysis has been conducted. The pressure controllability in SG is highly affected by the heat transfer characteristics of air which flows outside of the heat exchanger tube of the radiator. In order to verify a numerical analysis code of the cooling system, the heat transfer characteristics of air has been investigated with experimental results of a mock-up model test. It was confirmed that numerical analysis results were agreed well with experimental results, and the analysis code was successfully verified.
Maeda, Yukimasa; Nishihara, Tetsuo; Ohashi, Hirofumi; Sato, Hiroyuki; Inagaki, Yoshiyuki
JAERI-Data/Code 2005-001, 149 Pages, 2005/03
A heat and mass balance analysis code (N-HYPAC) has been developed to investigate transient behavior in the HTTR hydrogen production system. The code can analyze heat and mass transfer (temperature and mass and pressure distributions of process and helium gases) and behavior of the control system under both static state(case of steady operation) and dynamic state(case of transient operation). Analysis model of helium and process gases from IHX to secondary helium loop and hydrogen production system has been constructed. This report describes analytical flow sheet, construction of the code, basic equations, method to treat the input data, estimation of the preliminary analysis.
Inaba, Yoshitomo; Ohashi, Hirofumi; Nishihara, Tetsuo; Sato, Hiroyuki; Inagaki, Yoshiyuki; Takeda, Tetsuaki; Hayashi, Koji; Takada, Shoji
Nuclear Engineering and Design, 235(1), p.111 - 121, 2005/01
Prior to the connection of a hydrogen production plant to the HTTR, the fluctuation tests of the chemical reaction in the steam reformer with the mock-up test facility of the HTTR hydrogen production system were carried out for the establishment and demonstration of the control technology. As a result, it was shown that the HTTR hydrogen production system with the same control system as the mock-up test facility can provide stable controllability for any disturbance at the steam reformer without the influence to the reactor. In addition, a dynamic simulation code for the HTTR hydrogen production system was verified with the obtained test data.
Ogawa, Masuro; Nishihara, Tetsuo
Nuclear Engineering and Design, 233(1-3), p.5 - 10, 2004/10
An amount of primary energy supply in Japan is increasing year by year. Much energy such as oil, coal and natural gas is imported so that the self-sufficiency ratio in Japan is only 20 % even if including nuclear energy. An amount of energy consumption is also increasing especially in commercial and resident sector and transport sector. As a result, a large amount of greenhouse gas was emitted into the environment. Nuclear energy plays the important role in energy supply in Japan. Japan Atomic Energy Research Institute (JAERI) has been carried out research and development of a hydrogen production system using a high temperature gas cooled reactor (HTGR). The HTTR project aims at the establishment of the HTGR hydrogen production system. Reactor technology of the HTGR, hydrogen production technology with thermochemical water splitting process and system integration technology between the HTGR and a hydrogen production plant are developed in the HTTR project.
Shimizu, Akira; Nishihara, Tetsuo; Moriyama, Koichi*
JAERI-Tech 2004-051, 69 Pages, 2004/06
HTTR of JAERI will be connected with a hydrogen production system by steam reforming of methane for development of nuclear heat utilization technology. This facility will handle much inflammable gas near the nuclear reactor so that special safety consideration is necessary. This report describes the Probabilistic Safety Assessment (PSA) of inflammable gas leakage in the HTTR hydrogen production system. Vessels and pipes, which contain flammable gas, were divided into several systems. Probability of gas leakage were calculated at all candidate places. As a result of assessment, the counter measures such as double-covered inflammable gas pipes, small diameter instrument pipes, leakage detector and emergency shut off valves, are confirmed to be very effective to minimize the scale of explosion and to prevent the damage on nuclear plant.
Takeda, Tetsuaki; Iwatsuki, Jin*
Nuclear Technology, 146(1), p.83 - 95, 2004/04
The objective of this study is to investigate the effect of the existence of hydrogen in a pipe outside on the amount of permeated deuterium through the pipe. It was found that the amount of permeated deuterium decreases with increasing the partial pressure of hydrogen in the pipe outside when the partial pressure of deuterium in the pipe is lower than 100 Pa and that of hydrogen in the pipe outside is higher than 10 kPa. The amount of permeated deuterium on counter permeation was predicted quantitatively by using an effectiveness factor for diffusivity of deuterium in metals and by taking into account the equilibrium state for hydrogen, deuterium and HD molecules on the metal surface. From the results obtained in this study, it is supposed that the amount of tritium transferred from the primary circuit of the HTTR to the hydrogen production system will be reduced by the existence of high-pressure hydrogen in the catalyst pipe of the steam reformer.
Inaba, Yoshitomo; Nishihara, Tetsuo; Nitta, Yoshikazu*
Nuclear Technology, 146(1), p.49 - 57, 2004/04
One of the most important safety design issues for a hydrogen production system coupling with a High Temperature Gas-cooled Reactor (HTGR) is to ensure reactor safety against fire and explosion accidents because a large amount of combustible fluid is dealt with in the system. The Japan Atomic Energy Research Institute (JAERI) has a demonstration test plan of a hydrogen production system by steam reforming of methane coupling with the High Temperature engineering Test Reactor (HTTR). In the plan, we developed the P2A code system to analyze event sequences and consequences in detail on the fire and explosion accidents assumed in the HTGR or HTTR hydrogen production system. This paper described the three accident scenarios assumed in the system, the structure of P2A, the analysis procedure with P2A and the results of the numerical analyses based on the accident scenarios, and it was showed that P2A was a useful tool for the accident analysis in the system.
Takeda, Tetsuaki; Iwatsuki, Jin*; Inagaki, Yoshiyuki
Journal of Nuclear Materials, 326(1), p.47 - 58, 2004/03
Permeation of hydrogen isotope through a high-temperature alloy used as heat exchanger and steam reformer pipes is an important problem in the hydrogen production system connected to be a High-Temperature Engineering Test Reactor (HTTR). An experiment of hydrogen (H) and deuterium (D) permeation was performed to obtain permeability of H and D of Hastelloy XR, which is adopted as heat transfer pipe of an intermediate heat exchanger of the HTTR. Permeability of H and D of Hastelloy XR were obtained as follows. The activation energy E and pre-exponential factor F of the permeability of H was E=67.21.2 kJ/mol and F=(1.00.2)10m(STP)/m/s/Pa, respectively, in the pipe temperature ranging from 843K-1093K.
Ohashi, Hirofumi; Inaba, Yoshitomo; Nishihara, Tetsuo; Inagaki, Yoshiyuki; Takeda, Tetsuaki; Hayashi, Koji; Katanishi, Shoji; Takada, Shoji; Ogawa, Masuro; Shiozawa, Shusaku
Journal of Nuclear Science and Technology, 41(3), p.385 - 392, 2004/03
Prior to construction of a HTTR hydrogen production system, a mock-up test facility was constructed to investigate transient behavior of the hydrogen production system and to establish system controllability. The Mock-up test facility with a full-scale reaction tube is an approximately 1/30 scale model of the HTTR hydrogen production system and an electric heater is used as a heat source instead of a reactor. Before the mock-up test, a performance test of the test facility was carried out in the same pressure and temperature conditions as those of the HTTR hydrogen production system to investigate its performance such as hydrogen production ability, controllability and so on. It was confirmed that hydrogen was stably produced with a hot helium gas about 120Nm/h which satisfy the design value and thermal disturbance of helium gas during the start-up could be mitigated within the design value by using a steam generator.
Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 4 Pages, 2004/00
no abstracts in English
Nishihara, Tetsuo; Shimizu, Akira; Inagaki, Yoshiyuki; Tanihira, Masanori*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 2(4), p.517 - 524, 2003/12
no abstracts in English
Takeda, Tetsuaki; Ohashi, Hirofumi; Inagaki, Yoshiyuki
Nihon Kikai Gakkai 2003-Nendo Nenji Taikai Koen Rombunshu, Vol.3, p.17 - 18, 2003/08
A technology development of a hydrogen production system by a nuclear heat are being performed as a heat application system of a high-temperature gas cooled reactor in the Japan Atomic Energy Research Institute. The objective of this study is to clarify heat transfer characteristics of the steam reformer in the HTTR hydrogen production system. An experiment has been performed using a double coaxial vertical tube to obtain the heat transfer characteristics and to evaluate the effectiveness of heat transfer enhancement. The amount of produced hydrogen increases with increasing not only reaction rate of catalysis but also the heat transfer coefficient. It is necessary to take into account of heat transfer from both surfaces of the double coaxial tube in order to obtain the amount of transferred heat from the heated tube to the coolant gas.
Inagaki, Yoshiyuki; Hayashi, Koji; Kato, Michio; Fujisaki, Katsuo; Aita, Hideki; Takeda, Tetsuaki; Nishihara, Tetsuo; Inaba, Yoshitomo; Ohashi, Hirofumi; Katanishi, Shoji; et al.
JAERI-Tech 2003-034, 129 Pages, 2003/05
no abstracts in English
Nishihara, Tetsuo; Shimizu, Akira; Tanihira, Masanori*; Uchida, Shoji*
JAERI-Tech 2002-101, 46 Pages, 2003/01
no abstracts in English
Nishihara, Tetsuo; Inagaki, Yoshiyuki
Proceedings of GLOBAL2003 Atoms for Prosperity; Updating Eisenhower's Global Vision for Nuclear Energy (CD-ROM), p.320 - 324, 2003/00
HTGR hydrogen production system has potential possibility to provide hydrogen without CO emission. Key technology for developing this system is to establish the control technology for preventing propagation of thermal turbulence from the hydrogen production system to the HTGR. Japan Atomic Energy Research Institute (JAERI) has planed a demonstration test of hydrogen production using an HTGR named high temperature engineering test reactor (HTTR) to develop the control technology. Thermal load absorber concept using the steam generator located downstream of the chemical reactor is proposed to mitigate the variation of outlet helium temperature of the chemical reactor. This concept leads to the stable controllability and enables to operate the HTGR and the hydrogen production plant independently. Plant simulation analyses are carried out to verify the performance of this concept.