Derivation of ideal power distribution to minimize the maximum kernel migration rate for nuclear design of pin-in-block type HTGR

Okita, Shoichiro; Fukaya, Yuji; Goto, Minoru

Journal of Nuclear Science and Technology, 58(1), p.9 - 16, 2021/01

https://doi.org/10.1080/00223131.2020.1791762

Suppressing the kernel migration rates, which depend on both the fuel temperature and the fuel temperature gradient, under normal operation condition is quite important from the viewpoint of the fuel integrity for High Temperature Gas-cooled Reactors. The presence of the ideal axial power distribution to minimize the maximum kernel migration rate allows us to improve efficiency of design work. Therefore, we propose a new method based on Lagrange multiplier method in consideration of thermohydraulic design in order to obtain the ideal axial power distribution to minimize the maximum kernel migration rate. For one of the existing conceptual designs performed by JAEA, the maximum kernel migration rate for the power distribution to minimize the maximum kernel migration rate proposed in this study is lower by approximately 10% than that for the power distribution as a conventional design target to minimize the maximum fuel temperature.

Study on plutonium burner high temperature gas-cooled reactor in Japan; Introduction scenario, reactor safety and fabrication tests of the 3S-TRISO fuel

Ueta, Shohei; Mizuta, Naoki; Fukaya, Yuji; Goto, Minoru; Tachibana, Yukio; Honda, Masaki*; Saiki, Yohei*; Takahashi, Masashi*; Ohira, Koichi*; Nakano, Masaaki*; et al.

Nuclear Engineering and Design, 357, p.110419_1 - 110419_10, 2020/02

https://doi.org/10.1016/j.nucengdes.2019.110419

The concept of a plutonium (Pu) burner HTGR is proposed to incarnate highly-effective Pu utilization by its inherent safety features. The security and safety fuel (3S-TRISO fuel) employs the coated fuel particle with a fuel kernel made of plutonium dioxide (PuO) and yttria stabilized zirconia (YSZ) as an inert matrix. This paper presents feasibility study of Pu burner HTGR and R&D on the 3S-TRISO fuel.

Development of security and safety fuel for Pu-burner HTGR; Test and characterization for ZrC coating

Ueta, Shohei; Aihara, Jun; Goto, Minoru; Tachibana, Yukio; Okamoto, Koji*

Mechanical Engineering Journal (Internet), 5(5), p.18-00084_1 - 18-00084_9, 2018/10

https://doi.org/10.1299/mej.18-00084

To develop the security and safety fuel (3S-TRISO fuel) for Pu-burner high temperature gas-cooled reactor (HTGR), R&D on zirconium carbide (ZrC) directly coated on yttria stabilized zirconia (YSZ) has been started in the Japanese fiscal year 2015. As results of the direct coating test of ZrC on the dummy YSZ particle, ZrC layers with 18 - 21 microns of thicknesses have been obtained with 0.1 kg of particle loading weight. No deterioration of YSZ exposed by source gases of ZrC bromide process was observed by Scanning Transmission Electron Microscope (STEM).

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.

Reprocessing technologies of the High Temperature Gas-cooled Reactor (HTGR) fuel

Sumita, Junya; Ueta, Shohei; Kunitomi, Kazuhiko; Yoshimuta, Shigeharu*; Sawa, Kazuhiro

Nihon Genshiryoku Gakkai Wabun Rombunshi, 2(4), p.546 - 554, 2003/12

https://doi.org/10.3327/taesj2002.2.546

A High Temperature Gas-Cooled Reactor (HTGR) is particularly attractive due to capability of producing high temperature helium gas and its inherent safety characteristic. Research and development of high temperature gas turbine plant and high temperature heat utilizing technology are now undergoing. The High Temperature Engineering Test Reactor (HTTR) is a research facility constructed by the Japan Atomic Energy Research Institute. This paper describes reprocessing technology of HTGR fuels. Coated fuel particles, consisted of a microsphere of low enriched UO with TRISO particles, are used as the HTGR fuels. In order to reprocess HTGR fuels, a head-end process is needed and JAERI had confirmed jet-grind method as basic technologies of the head-end process. Since Purex method can be used after the head-end process, a reprocessing system for the HTGR fuels could be established. Also the preliminary study on the methodology for disposing graphite blocks in a HTGR was carried out, and its evaluation results were briefly presented.

The High temperature gas cooled reactor fuel

Sawa, Kazuhiro; Ueta, Shohei; Iyoku, Tatsuo

Proceedings of International Conference on Global Environment and Advanced Nuclear Power Plants (GENES4/ANP 2003) (CD-ROM), 10 Pages, 2003/09

This paper provides present status of research and development for the coated fuel particle (CFPs) including the advanced ZrC-CFP. Current HTGR employs so-called TRISO-CFPs with SiC layer. In safety design of the HTGR fuels, it is important to retain fission products within CFPs so that their release to primary coolant does not exceed an acceptable level. The behavior of TRISO-CFPs has been investigated through experiments and reactor operation. These data show excellent performance of the TRISO-CFPs when they are correctly fabricated. On the other hand, the crystalline material comprising the SiC layer has a tendency to decompose at high temperature. The transition temperatures of beta-SiC (as-deposited) to alpha-SiC vary from 1600 to 2200C. ZrC is one of the transition metal carbides which are characterized by the high melting point and the thermodynamic stability etc. The CFPs with CVD-ZrC coatings have been investigated including the fabrication processes and characterization techniques developments.

Comparison of HTGR fuel design, manufacture and quality control methods between Japan and China

Fu, X.*; Takahashi, Masashi; Ueta, Shohei; Sawa, Kazuhiro

JAERI-Tech 2002-049, 35 Pages, 2002/05

JAERI-Tech-2002-049.pdf:3.01MB

no abstracts in English

Safety criteria and quality control of HTTR fuel

Sawa, Kazuhiro; Suzuki, Shuichi*; Shiozawa, Shusaku

Nuclear Engineering and Design, 208(3), p.305 - 313, 2001/09

https://doi.org/10.1016/S0029-5493(01)00358-2

no abstracts in English

Integrity confirmation tests and post-irradiation test plan of the HTTR first-loading fuel

Sawa, Kazuhiro; Sumita, Junya; Ueta, Shohei; Suzuki, Shuichi*; Tobita, Tsutomu*; Saito, Takashi; Minato, Kazuo; Koya, Toshio; Sekino, Hajime

Journal of Nuclear Science and Technology, 38(6), p.403 - 410, 2001/06

https://doi.org/10.3327/jnst.38.403

no abstracts in English

A Study of fuel failure behavior in high burnup HTGR fuel; Analysis by STRESS3 and STAPLE codes

Martin, D. G.*; Sawa, Kazuhiro; Ueta, Shohei; Sumita, Junya

JAERI-Research 2001-033, 19 Pages, 2001/05

JAERI-Research-2001-033.pdf:1.2MB

no abstracts in English