Development of safety design philosophy of HTTR-Heat Application Test Facility

Aoki, Takeshi; Shimizu, Atsushi; Noguchi, Hiroki; Kurahayashi, Kaoru; Yasuda, Takanori; Nomoto, Yasunobu; Iigaki, Kazuhiko; Sato, Hiroyuki; Sakaba, Nariaki

Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 9 Pages, 2023/05

The safety design philosophy is developed for the HTTR (High Temperature Engineering Test Reactor) heat application test facility connecting high temperature gas-cooled reactor (HTGR) and the hydrogen production plant. The philosophy was proposed to apply proven conventional chemical plant standards to the hydrogen production facility for ensuring public safety against anticipated disasters caused by high pressure and combustible gases. The present study also proposed the safety design philosophy to meet specific safety requirements identified to the nuclear facilities with coupling to the hydrogen production facility such as measures to ensure a capability of normal operation of the nuclear facility against a fire and/or explosion of leaked combustible material, and fluctuation of amount of heat removal occurred in the hydrogen production plant. The safety design philosophy will be utilized to establish its basic and detailed designs of the HTTR-heat application test facility.

Development plan for coupling technology between high temperature gas-cooled reactor HTTR and Hydrogen Production Facility, 2; Development plan for coupling equipment between HTTR and Hydrogen Production Facility

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

Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 6 Pages, 2023/05

Rabi-oscillation spectroscopy of the hyperfine structure of muonium atoms

Nishimura, Shoichiro*; Torii, Hiroyuki*; Fukao, Yoshinori*; Ito, Takashi; Iwasaki, Masahiko*; Kanda, Sotaro*; Kawagoe, Kiyotomo*; Kawall, D.*; Kawamura, Naritoshi*; Kurosawa, Noriyuki*; et al.

Physical Review A, 104(2), p.L020801_1 - L020801_6, 2021/08

https://doi.org/10.1103/PhysRevA.104.L020801

Effects of residual stress on hydrogen embrittlement of a stretch-formed tempered martensitic steel sheet

Nishimura, Hayato*; Hojo, Tomohiko*; Ajita, Saya*; Shibayama, Yuki*; Koyama, Motomichi*; Saito, Hiroyuki*; Shiro, Ayumi*; Yasuda, Ryo*; Shobu, Takahisa; Akiyama, Eiji*

ISIJ International, 61(4), p.1170 - 1178, 2021/04

https://doi.org/10.2355/isijinternational.ISIJINT-2020-492

Hydrogen embrittlement resistance of pre-strained ultra-high-strength low alloy TRIP-aided steel

Hojo, Tomohiko*; Kumai, B.*; Koyama, Motomichi*; Akiyama, Eiji*; Waki, Hiroyuki*; Saito, Hiroyuki*; Shiro, Ayumi*; Yasuda, Ryo*; Shobu, Takahisa; Nagasawa, Akihiko*

International Journal of Fracture, 224(2), p.253 - 260, 2020/08

https://doi.org/10.1007/s10704-020-00451-5

In the study, the pre-strain effect on hydrogen embrittlement property of the ultra-high-strength transformation-induced plasticity -aided bainitic ferrite steel was investigated towards application for automobile frame parts. 3-10% tensile pre-strain suppressed hydrogen-induced mechanical degradation relative to total elongation while 12-15% pre-strained specimen did not exhibit elongation after hydrogen charging. The advantageous effect of the 3-10% pre-strain was attributed to the suppression of crack initiation related to retained austenite. The TRIP by pre-straining decreased the volume fraction of retained austenite before hydrogen charging, thereby reducing existing probabilities of preferential crack initiation sites and propagation paths. Conversely, high pre-strain such as 12-15% does not effectively work due to work hardening resulting in increases in hydrogen embrittlement susceptibility and a significant increase in hydrogen content due to the multiplication of dislocations.

Study on formation mechanism of {332}113 deformation twinning in metastable -type Ti alloy focusing on stress-induced martensite phase

Cho, K.*; Morioka, Ryota*; Harjo, S.; Kawasaki, Takuro; Yasuda, Hiroyuki*

Scripta Materialia, 177, p.106 - 111, 2020/03

https://doi.org/10.1016/j.scriptamat.2019.10.011

Enhancement of element production by incomplete fusion reaction with weakly bound deuteron

Wang, H.*; Otsu, Hideaki*; Chiga, Nobuyuki*; Kawase, Shoichiro*; Takeuchi, Satoshi*; Sumikama, Toshiyuki*; Koyama, Shumpei*; Sakurai, Hiroyoshi*; Watanabe, Yukinobu*; Nakayama, Shinsuke; et al.

Communications Physics (Internet), 2(1), p.78_1 - 78_6, 2019/07

https://doi.org/10.1038/s42005-019-0165-1

Searching for effective pathways for the production of proton- and neutron-rich isotopes through an optimal combination of reaction mechanism and energy is one of the main driving forces behind experimental and theoretical nuclear reaction studies as well as for practical applications in nuclear transmutation of radioactive waste. We report on a study on incomplete fusion induced by deuteron, which contains one proton and one neutron with a weak binding energy and is easily broken up. This reaction study was achieved by measuring directly the cross sections for both proton and deuteron for Pd at 50 MeV/u via inverse kinematics technique. The results provide direct experimental evidence for the onset of a cross-section enhancement at high energy, indicating the potential of incomplete fusion induced by loosely-bound nuclei for creating proton-rich isotopes and nuclear transmutation of radioactive waste.

Analysis of the radioactivity concentrations in low-level radioactive waste generated from JPDR facilities, 4

Omori, Hiroyuki; Nebashi, Koji; Shimada, Asako; Tanaka, Kiwamu; Yasuda, Mari; Hoshi, Akiko; Tsuji, Tomoyuki; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Data/Code 2014-029, 31 Pages, 2015/03

JAEA-Data-Code-2014-029.pdf:1.51MB

Simple and rapid methods to evaluate the radioactivity concentrations are required for the radioactive waste generated from research facilities in the Japan Atomic Energy Agency to dispose of in a near-surface repository. In order to establish the methods to evaluate the radioactivity concentrations of miscellaneous solid waste generated from research and testing reactors, we collected and analyzed samples from miscellaneous solid waste generated by the decommissioning of JPDR (Japan Power Demonstration Reactor). In this report, we reported the analytical data determined in fiscal 2014 (Cs and Mo) and summarized them with the radioactivity concentrations obtained in the past as basic data to consider the evaluation method of radioactivity concentrations in the stored waste taken from JPDR.

Hydrogen concentration measurement in fuel cladding by backscattered electron image analysis

Onozawa, Atsushi; Harada, Akio; Honda, Junichi; Yasuda, Ryo; Nakata, Masahito; Kanazawa, Hiroyuki; Nishino, Yasuharu

JAEA-Technology 2006-010, 19 Pages, 2006/03

JAEA-Technology-2006-010.pdf:2.3MB

A measurement technique for hydrogen concentration using Backscattered Electron Image analysis (BEI method) had been developed by Studsvik Nuclear AB, Sweden. The hydrides in claddings are identified using BEIs which are imaged with Scanning Electron Microscope, and the hydrogen concentrations are calculated from the area fractions of the hydrides in the matrix. The BEI method is very useful for the measurement in local hydrogen concentrations of fuel claddings. In the Reactor Fuel Examination Facility, a sample preparation, imaging conditions of SEM and image analysis procedures for the BEI method were improved. In addition, the hydrogen concentrations obtained by the improved BEI method and Hot Vacuum Extraction (HVE) method were compared to confirm the reliability of the improved BEI method. The results showed, the improved BEI method has the same reliability as that of HVE method and can be applied for the Post-Irradiation Examination.

Current status of neutron radiography in JRR-3

Yasuda, Ryo; Nojima, Takehiro; Iikura, Hiroshi; Sakai, Takuro; Matsubayashi, Masahito; Yamamoto, Hiroyuki

no journal, , 

Development of large-scale hydrogen production technology utilizing very high temperature, 2-2; Designs of secondary helium cooling equipment for HTTR-Heat Application Test Facility

Ishii, Katsunori; Mizuta, Naoki; Morita, Keisuke; Aoki, Takeshi; Kurahayashi, Kaoru; Yasuda, Takanori; Noguchi, Hiroki; Nomoto, Yasunobu; Shimizu, Atsushi; Iigaki, Kazuhiko; et al.

no journal, , 

no abstracts in English