Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Takeda, Tetsuaki*; Inagaki, Yoshiyuki; Aihara, Jun; Aoki, Takeshi; Fujiwara, Yusuke; Fukaya, Yuji; Goto, Minoru; Ho, H. Q.; Iigaki, Kazuhiko; Imai, Yoshiyuki; et al.
High Temperature Gas-Cooled Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.5, 464 Pages, 2021/02
As a general overview of the research and development of a High Temperature Gas-cooled Reactor (HTGR) in JAEA, this book describes the achievements by the High Temperature Engineering Test Reactor (HTTR) on the designs, key component technologies such as fuel, reactor internals, high temperature components, etc., and operational experience such as rise-to-power tests, high temperature operation at 950
C, safety demonstration tests, etc. In addition, based on the knowledge of the HTTR, the development of designs and component technologies such as high performance fuel, helium gas turbine and hydrogen production by IS process for commercial HTGRs are described. These results are very useful for the future development of HTGRs. This book is published as one of a series of technical books on fossil fuel and nuclear energy systems by the Power Energy Systems Division of the Japan Society of Mechanical Engineers.
Ono, Masato; Fujiwara, Yusuke; Matsumoto, Tetsuro*; Iigaki, Kazuhiko
Nihon Genshiryoku Gakkai Wabun Rombunshi, 19(2), p.110 - 120, 2020/06
Integrity confirmation for buildings against collisions of projectiles has been conducted to evaluate collisions between a projectile with simple shape and a wall using empirical formulas. It is a matter of fact, there is a possibility that structures with complex shape such as stack may collide with a reactor building. However, there were not so many studies of collisions between structures with complex shape and buildings in the literature. Impact evaluation was carried out using reactor building and stack with real shape and adequate physical property. It was found that ceiling of reactor building was not damaged by the collision, confirming that there was no effect inside of reactor building.
Ishii, Toshiaki; Shimazaki, Yosuke; Ono, Masato; Fujiwara, Yusuke; Ishitsuka, Etsuo; Hamamoto, Shimpei
Proceedings of 9th International Topical Meeting on High Temperature Reactor Technology (HTR 2018) (USB Flash Drive), 3 Pages, 2018/10
Ono, Masato; Fujiwara, Yusuke; Iigaki, Kazuhiko; Matsumoto, Tetsuro*; Taki, Nobuhiro*
Proceedings of European Research Reactor Conference 2018 (RRFM 2018) (Internet), 7 Pages, 2018/03
Integrity confirmation of building against the crash of flying object due to the tornado was carried out by formulas which calculate by simple shape. However, there was no study on crash calculation using complex shape such as the stack and reactor building. In this study, the crash calculation was carried out by a real shape model of High Temperature Engineering Test Reactor (HTTR) stack and reactor building using three-dimensional analysis code (VPS: Virtual Performance Solution). In the calculation, parameters of VPS were conservatively set in accordance with the formulas, which are formulated based on results of crash experiments and approved by the Nuclear Regulatory Authority. The crash calculation of stack and reactor building of HTTR was carried out using VPS. As a result, the integrity of building against the crash by stack was confirmed.
Fujiwara, Yusuke; Nemoto, Takahiro; Tochio, Daisuke; Shinohara, Masanori; Ono, Masato; Takada, Shoji
Journal of Nuclear Engineering and Radiation Science, 3(4), p.041013_1 - 041013_8, 2017/10
In HTTR, the test was carried out at the reactor thermal power of 9 MW under the condition that one cooling line of VCS was stopped to simulate the partial loss of cooling function from the surface of RPV in addition to the loss of forced cooling flow in the core simulation. The test results showed that temperature change of the core internal structures and the biological shielding concrete was slow during the test. Temperature of RPV decreased several degrees during the test. The temperature decrease of biological shielding made of concrete was within 1C. The numerical result simulating the detail configuration of the cooling tubes of VCS showed that the temperature rise of cooling tubes of VCS was about 15C, which is sufficiently small, which did not significantly affect the temperature of biological shielding concrete. As the results, it was confirmed that the cooling ability of VCS can be kept in case that one cooling line of VCS is lost.
Ono, Masato; Fujiwara, Yusuke; Honda, Yuki; Sato, Hiroyuki; Shimazaki, Yosuke; Tochio, Daisuke; Homma, Fumitaka; Sawahata, Hiroaki; Iigaki, Kazuhiko; Takada, Shoji
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 5 Pages, 2017/04
Japan Atomic Energy Agency (JAEA) has carried out research and developments towards nuclear heat utilization of High Temperature Gas-cooled Reactor (HTGR) using High Temperature Engineering Test Reactor (HTTR). The nuclear heat utilization systems connected to HTGR will be designed on the basis of non-nuclear-grade standards in terms of easier entry for the chemical plant companies and the construction economics of the systems. Therefore, it is necessary that the reactor operations continue even if abnormal events occur in the systems. Heat application system abnormal simulating test with HTTR was carried out in non-nuclear heating operation to focus on the thermal effect in order to obtain data of the transient temperature behavior of the metallic components in the Intermediate Heat Exchanger (IHX). The IHX is the key components to connect the HTTR with the heat application system. In the test, the coolant helium gas temperature was heated up to 120C by the compression heat of the gas circulators in the HTTR under the ideal condition to focus on the heat transfer. The tests were conducted by decreasing the helium gas temperature stepwise by increasing the mass flow rate to the air cooler. The temperature responses of the IHX were investigated. For the components such as the heat transfer tubes and heat transfer enhancement plates of IHX, the temperature response was slower in the lower position in comparison with the higher position. The reason is considered that thermal load fluctuation is imposed in the secondary helium gas which flows from the top to the bottom in the heat transfer tubes of the IHX. The test data are useful to verify the numerical model of the safety evaluation code.
Fujiwara, Yusuke; Nemoto, Takahiro; Tochio, Daisuke; Shinohara, Masanori; Ono, Masato; Hamamoto, Shimpei; Iigaki, Kazuhiko; Takada, Shoji
Proceedings of 24th International Conference on Nuclear Engineering (ICONE-24) (DVD-ROM), 7 Pages, 2016/06
In HTTR, the test was carried out at the reactor thermal power of 9 MW under the condition that one cooling line of VCS was stopped to simulate the partial loss of cooling function from the surface of RPV in addition to the loss of forced cooling flow in the core simulation. The test results showed that temperature change of the core internal structures and the biological shielding concrete was slow during the test. Temperature of RPV decreased several degrees during the test. The temperature decrease of biological shielding made of concrete was within 1C. The numerical result simulating the detail configuration of the cooling tubes of VCS showed that the temperature rise of cooling tubes of VCS was about 15 degree C, which is sufficiently small, which did not significantly affect the temperature of biological shielding concrete. As the results, it was confirmed that the cooling ability of VCS can be kept in case that one cooling line of VCS is lost.
Sawahata, Hiroaki; Shimazaki, Yosuke; Ishitsuka, Etsuo; Yamazaki, Kazunori; Yanagida, Yoshinori; Fujiwara, Yusuke; Takada, Shoji; Shinozaki, Masayuki; Hamamoto, Shimpei; Tochio, Daisuke
Proceedings of 24th International Conference on Nuclear Engineering (ICONE-24) (DVD-ROM), 8 Pages, 2016/06
In the HTTR, 
Cf is loaded in the reactor core as a neutron startup source and changed at frequency. In this exchange work, there were two technical issues; slightly higher radiation exposure of workers by neutron leakage and reliability of neutron source transportation container in handling. To reduce the radiation dose by neutron leakage, detail numerical evaluations using PHITS code were carried out, the effective shielding method for fuel handling machine was proposed. Easily removable polyethylene blocks and particles were used as the neutron shielding, and installed in the cooling paths of the fuel handling machine. As a result, the collective effective dose by neutron was reduced from about 700 man-microSv to about 300 man-microSv. As to the neutron source transportation container, the handling performance was improved and the handling work was safety accomplished by downsizing.
Tochio, Daisuke; Fujiwara, Yusuke; Ono, Masato; Shinohara, Masanori; Hamamoto, Shimpei; Iigaki, Kazuhiko; Takada, Shoji
Proceedings of 24th International Conference on Nuclear Engineering (ICONE-24) (DVD-ROM), 9 Pages, 2016/06
From the HTTR operational experience, it is needed to clear the thermal mixing characteristics of the helium gas at the annulus of the co-axial double-walled piping in HTGR. In this paper, thermal-hydraulic analysis on the helium gas at the annular flow path of the co-axial double pipe with T-junction was conducted. The analysis was performed under the condition of the different annular flow path height and with the different flow rate of the higher- and the lower-temperature helium gas. It is shown that the thermal mixing behavior is not so much affected by the flow rate of higher- and lower-temperature helium gas, and it is difficult to mix the helium gas with the smaller height of the annular flow path. It is confirmed that it is difficult to mix the helium gas in the annular flow path of the co-axial double-walled piping by using the hydraulic behavior, and it is necessary to arrange the mixing promotor in the annular flow path.
Honda, Yuki; Tochio, Daisuke; Sato, Hiroyuki; Nakagawa, Shigeaki; Ono, Masato; Fujiwara, Yusuke; Hamamoto, Shimpei; Iigaki, Kazuhiko; Takada, Shoji
Proceedings of 24th International Conference on Nuclear Engineering (ICONE-24) (DVD-ROM), 5 Pages, 2016/06
The characteristic confirmation test has been demonstrating by using the High Temperature engineering Test Reactor (HTTR). The thermal load fluctuation test, which is one of marginal performance test is planned to be carried out after restarting of the HTTR. The preliminary analysis for the thermal load fluctuation test has been investigated. In the analysis, the reactor outlet temperature can continue to be stable against the reactor inlet temperature changing by thermal fluctuation. It means that HTGR have the capability of absorbing thermal fluctuation. This paper focuses on the investigation of mechanism of absorbing thermal fluctuation. With additional analysis, it is cleared that the large negative graphite moderator reactivity enhances the capability of absorbing thermal fluctuation. In addition, in the middle of the core, graphite moderator reactivity insertion trend are inverted. This trend is unique to HTGR because of large temperature difference between core inlet and outlet.
Hamamoto, Shimpei; Fujiwara, Yusuke; Kawamoto, Taiki; Saikusa, Akio
no journal, ,
A leakage measurement system of primary coolant helium leaked from the bolt fastening flange was constructed at the High Temperature engineering Test Reactor (HTTR). In addition to the helium leakage from the flange, the primary helium pressure, the helium temperature, and the temperature of the flange were measured. The data demonstrated that temperature change of one flange in short-term was associated with tens of percent reduction of helium leakage from bolt fastening flange.
Ishitsuka, Etsuo; Kondo, Makoto; Fujiwara, Yusuke; Ishii, Toshiaki; Hamamoto, Shimpei
no journal, ,
no abstracts in English
