Development of coupling technology for high temperature gas-cooled reactors and hydrogen production facility; HTTR heat application test project plan

Ishii, Katsunori; Morita, Keisuke; Noguchi, Hiroki; Aoki, Takeshi; Mizuta, Naoki; Hasegawa, Takeshi; Nagatsuka, Kentaro; Nomoto, Yasunobu; Shimizu, Atsushi; Iigaki, Kazuhiko; et al.

Dai-27-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (Internet), 4 Pages, 2023/09

https://doi.org/10.1299/jsmepes.2023.27.A242

Development plan for coupling technology between high temperature gas-cooled reactor HTTR and hydrogen production facility, 1; Overview of the HTTR heat application test plan to establish high safety coupling technology

Nomoto, Yasunobu; Mizuta, Naoki; Morita, Keisuke; Aoki, Takeshi; Okita, Shoichiro; Ishii, Katsunori; Kurahayashi, Kaoru; Yasuda, Takanori; Tanaka, Masato; Isaka, Kazuyoshi; et al.

Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 7 Pages, 2023/05

High temperature gas-cooled reactors

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

https://doi.org/10.1016/C2018-0-05383-9

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 950C, 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.

Contribution of membrane technology to hydrogen society; Development of membrane IS process

Inagaki, Yoshiyuki; Sakaba, Nariaki; Tanaka, Nobuyuki; Nomura, Mikihiro*; Sawada, Shinichi*; Yamaki, Tetsuya*

Nihon Kaisui Gakkai-Shi, 73(4), p.194 - 202, 2019/08

The thermochemical IS process is a promising hydrogen production method which can produce hydrogen in a large amount and stably with high efficiency by thermal splitting of water. Research and development on chemical reaction technology with membranes was conducted for the purpose of improving the efficiency of IS process and application of solar heat. The basic technology of ceramic membranes applied to decomposition reactions of hydrogen iodine and sulfuric acid was developed, and it is expected that the conversion rate on decomposition in each reaction can be remarkably improved. The basic technology of a cation exchange membrane applied to Bunsen reaction was developed with radiation-induced grafting technique, it is expected that the amount of iodine can be reduced to about one-fifth compared to the conventional method. These achievements are important technologies for practical use of the IS process.

Research and development on high burnup HTGR fuels in JAEA

Ueta, Shohei; Mizuta, Naoki; Sasaki, Koei; Sakaba, Nariaki; Ohashi, Hirofumi; Yan, X.

Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 8 Pages, 2019/05

JAEA has been progressing to design HTGR fuels for not only small-type practical HTGRs but also VHTR proposed in GIF which can be utilized for various purposes with high-temperature heat at 750 to 950 C. To increase economy of these HTGRs, JAEA has been upgrading the design method for the HTGR fuel, which can maintain their integrities at the burnup of three to four times higher than that of the conventional HTTR fuel. Design principles and specifications of various concepts of the high burnup HTGR fuels designed by JAEA are reported. As the latest results on post-irradiation examinations of the high burnup HTGR fuel progressing in a framework of international collaboration with Kazakhstan, irradiation shrinkage rate of the fuel compact as a function of fast neutron fluence was obtained at around 100 GWd/thm. Furthermore, the future R&Ds needed for the high burnup HTGR fuel are described based on these experimental results.

Shielding technology for upper structure of HTTR

Ueta, Shohei; Sakaba, Nariaki; Sawa, Kazuhiro

Annals of Nuclear Energy, 94, p.72 - 79, 2016/08

https://doi.org/10.1016/j.anucene.2016.02.021

In the shielding design for the High Temperature Gas-cooled Reactor (HTGR), special attentions shall be needed to avoid neutron streaming, since helium gas as a coolant does not work for shielding. Japan Atomic Energy Agency has demonstrated the performance of shielding through testing operations of the High Temperature Engineering Test Reactor (HTTR) in order to establish design method for shielding of the Very-High-Temperature Reactor (VHTR) as a Generation-IV nuclear power system. As results of the test, it was confirmed that dose equivalent rates for neutron and -ray at on-operating acceptable areas were less than detection limit and as low as background, respectively. The measured dose at the stand-pipe room corresponded to the detection limit, and it was found that over 90% of dose derived from fast neutron. It was indicated that there was still a margin of factor 50 in addition to the design which excluded the safety factor. The measured dose rates showed good agreement with the predicted considering the control rod withdrawing effect. The knowledge on the design method and the demonstration of shielding by the HTTR will strongly contribute to realizing and optimizing the designs of future VHTRs.

Energy neutral phosphate fertilizer production using high temperature reactors; A Philippine case study

Haneklaus, N.*; Reyes, R.*; Lim, W. G.*; Tabora, E. U.*; Palattao, B. L.*; Petrache, C.*; Vargas, E. P.*; Kunitomi, Kazuhiko; Ohashi, Hirofumi; Sakaba, Nariaki; et al.

Philippine Journal of Science, 144(1), p.69 - 79, 2015/06

http://philjournalsci.dost.gov.ph/vol144no1/energy%20neutral%20phosphate%20fertilizer%20production.html

The Philippines may profit from extracting uranium (U) from phosphoric acid during fertilizer production in a way that the recovered U can be beneficiated and taken as raw material for nuclear reactor fuel. Used in a high temperature reactor (HTR) that provides electricity and/or process heat for fertilizer processing and U extraction, energy-neutral fertilizer production, an idea first proposed by Haneklaus et al., is possible. This paper presents a first case study of the concept regarding a representative phosphate fertilizer plant in the Philippines and exemplary HTR designs (HTR50S and GTHTR300C) developed by the Japan Atomic Energy Agency (JAEA). Three different arrangements (version I-III), ranging from basic electricity supply to overall power supply including on site hydrogen production for ammonia conversion, are introduced and discussed.

Fuel performance under continuous high-temperature operation of the HTTR

Ueta, Shohei; Aihara, Jun; Sakaba, Nariaki; Honda, Masaki*; Furihata, Noboru*; Sawa, Kazuhiro

Journal of Nuclear Science and Technology, 51(11-12), p.1345 - 1354, 2014/11

https://doi.org/10.1080/00223131.2014.926230

Although the HTTR fuel was the first mass-produced HTGR fuel in Japan, it has been fabricated with the highest quality in the world on the basis of design principle and safety criteria to minimize both as-fabricated failure and on-operating-additional failure of the coated fuel particle. A precise technology for evaluating irradiation performance of the HTTR fuel has been developed by measuring fission gases released from fuel and constructing the fission gas release model. Through the HTTR operations including the continuous high temperature operation with 950 C and 50 days, the measured fractional release of fission gas from fuel resulted less than 1.2 10, and a superior irradiation performance of Japanese HTGR fuel has been demonstrated. The HTTR fuel technologies could make a prospect for realization of the practical HTGR as well as the VHTR as a Generation IV nuclear power plant before the rest of the world.

Safety design approach for the development of safety requirements for design of commercial HTGR

Ohashi, Hirofumi; Sato, Hiroyuki; Nakagawa, Shigeaki; Tachibana, Yukio; Nishihara, Tetsuo; Yan, X.; Sakaba, Nariaki; Kunitomi, Kazuhiko

Proceedings of 7th International Topical Meeting on High Temperature Reactor Technology (HTR 2014) (USB Flash Drive), 10 Pages, 2014/10

The research committee on Safety requirements for HTGR design was established in 2013 under the Atomic Energy Society of Japan to develop the draft safety requirements for the design of commercial High Temperature Gas-cooled Reactor (HTGR), which incorporate the HTGR safety features demonstrated using the High Temperature Engineering Test Reactor (HTTR), lessons learned from the accident of Fukushima Daiichi Nuclear Power Station and requirements for the integration of the hydrogen production plants. The safety design approach for the commercial HTGR which is a basement of the safety requirements is determined prior to the development of the safety requirements. This paper describes the main topics of the research committee, the safety design approaches and the safety functions of the commercial HTGR determined in the research committee.

R&D plan for development of oxidation-resistant graphite and investigation of oxidation behavior of SiC coated fuel particle to enhance safety of HTGR

Ueta, Shohei; Sumita, Junya; Shibata, Taiju; Aihara, Jun; Fujita, Ichiro*; Ohashi, Jun*; Nagaishi, Yoshihide*; Muto, Takenori*; Sawa, Kazuhiro; Sakaba, Nariaki

Nuclear Engineering and Design, 271, p.309 - 313, 2014/05

https://doi.org/10.1016/j.nucengdes.2013.11.052

A new concept of the high temperature gas-cooled reactor (HTGR) is proposed as a challenge to assure no event sequences to the harmful release of radioactive materials even when the design extension conditions (DECs) occur by deterministic approach based on the inherent safety features of the HTGR. The air/water ingress accident, one of the DECs for the HTGR, is prevented by additional measures (e.g. facility for suppression to air ingress). With regard to the core design, it is important to prevent recriticality accidents by keeping the geometry of the fuel rod which consists of the graphite sleeve, fuel compact and SiC-TRISO (TRIstructural-ISOtropic) coated fuel particle, and by improving the oxidation resistance of the graphite when air/water ingress accidents occur. Therefore, it is planned to develop the oxidation-resistant graphite, which is coated with gradient SiC layer. It is also planned that the experimental identification of the condition to form the stable oxide layer (SiO) for SiC layer on the oxidation-resistant graphite and on the SiC-TRISO fuel. This paper describes the R&D plan for un-irradiation and irradiation test under simulating air/water ingress accident condition to develop oxidation-resistant graphite and to investigate the oxidation behavior of SiC coated fuel particle.