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Saijo, Tomoaki; Shimazaki, Yosuke; Ishihara, Masahiro
JAEA-Technology 2025-010, 126 Pages, 2025/12
JAEA-Technology-2025-010.pdf:12.52MB
During the operation of the High Temperature Engineering Test Reactor (HTTR), thermal stress is generated in the graphite components. In addition, graphite exhibits dimensional shrinkage and creep deformation under neutron irradiation. As a result, residual stress remains in the graphite components during reactor shutdown. Therefore, in the design of the HTTR core graphite structures, stress analyses of the graphite components have previously been performed using the finite element analysis code VIENUS. In the HTTR, the graphite components are exposed to a wide range of temperature, from approximately 400
C to 1200C, depending on their location. Consequently, irradiation-induced behaviors such as material property changes and irradiation shrinkage vary among the graphite components. On the other hand, since VIENUS code evaluates stress based on thermal fluid and heat conduction analysis results, it is not suitable for parametric studies. In this study, the influence of irradiation behavior on the stress behavior of graphite components in the wide temperature range (400C to 1200C) was analyzed using simplified viscoelastic evaluation model, consisting of two beam elements, to conduct efficient parametric studies. Operational stress exhibits two distinct patterns depending on whether the irradiation temperature is below or above 800C, due to irradiation shrinkage. Residual stress approaches the thermal stress, preventing excessive increase even when irradiation shrinkage is large. Moreover good agreement in stress behavior trends was observed between the stress analysis results by the simplified viscoelastic evaluation model and VIENUS code. These results indicate that the simplified viscoelastic evaluation model is beneficial in simulating stress behavior.
Hirooka, Shun; Kato, Masato
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Next Generation Nuclear Systems for Sustainable Development (FR-17) (USB Flash Drive), 6 Pages, 2017/06
Young's modulus of MOX pellets was evaluated by measuring the sound velocities of longitudinal and transverse waves in the pellets as functions of porosity, oxygen-to-metal ratio (O/M) and plutonium content. The results showed that porosity was the most important factor that 20% of the porosity decreased Young's modulus by neatly 100 GPa while O/M and plutonium content could change the Young's modulus by ~20 GPa. From the measured sound velocities, temperature dependence on Young's modulus and specific heat capacity were calculated on the Debye model by leveraging the thermal expansion data. The temperature dependence that Young's modulus decreases with increasing temperature is in good agreement with literature data. The specific heat capacity also agrees with that of calculated value by Kopp's method, taken the Schottky term and the excited term into account.
Shibata, Taiju; Ishihara, Masahiro
Proceedings of International Conference on Advanced Technology in Experimental Mechanics 2003 (ATEM '03) (CD-ROM), 5 Pages, 2003/09
no abstracts in English
Shibata, Taiju; Ishihara, Masahiro
Transactions of 17th International Conference on Structural Mechanics in Reactor Technology (SMiRT-17) (CD-ROM), 8 Pages, 2003/08
no abstracts in English
Shibata, Taiju; Ishihara, Masahiro
Transactions of 16th International Conference on Structural Mechanics in Reactor Technology (SMiRT-16) (CD-ROM), 8 Pages, 2001/08
no abstracts in English
Shibata, Taiju; Ishihara, Masahiro; Takahashi, Tsuneo*; Motohashi, Yoshinobu*
Proceedings of Asian Pacific Conference on Fracture and Strength '01(APCFS '01) and International Conference on Advanced Technology in Experimental Mechanics '01 (ATEM '01), p.894 - 898, 2001/00
no abstracts in English
Ishihara, Masahiro; Shibata, Taiju; Baba, Shinichi; Hoshiya, Taiji; Wan, C.*; Motohashi, Yoshinobu*
Proceedings of OECD/NEA 2nd Information Exchange Meeting on Basic Studies in the Field of High-temperature Engineering, p.113 - 124, 2001/00
no abstracts in English
Ishihara, Masahiro; Shibata, Taiju; Takahashi, Tsuneo*; Baba, Shinichi; Hoshiya, Taiji
Proceedings of OECD/NEA 2nd Information Exchange Meeting on Basic Studies in the Field of High-temperature Engineering, p.225 - 241, 2001/00
no abstracts in English
Ishihara, Masahiro; Baba, Shinichi; Aihara, Jun; Hayashi, Kimio; Arai, Taketoshi; Ishino, Shiori*
Proceedings of 1st Information Exchange Meeting on Basic Studies on High-Temperature Engineering, p.299 - 308, 1999/09
no abstracts in English
Eto, Motokuni; Ishiyama, Shintaro; Fukaya, Kiyoshi; Saito, Tamotsu; Ishihara, Masahiro; Hanawa, Satoshi
JAERI-Research 98-003, 34 Pages, 1998/01
JAERI-Research-98-003.pdf:1.26MB
no abstracts in English
Kanari, Moriyasu*; ; ; Eto, Motokuni
Carbon, 35(10-11), p.1429 - 1437, 1997/00
Times Cited Count：40 Percentile：81.10(Chemistry, Physical)no abstracts in English
; ;
Nihon Genshiryoku Gakkai-Shi, 29(7), p.651 - 655, 1987/07
Times Cited Count：7 Percentile：59.17(Nuclear Science & Technology)no abstracts in English
;
JAERI-M 85-147, 48 Pages, 1985/09
no abstracts in English
;
J. Nucl. Mater., 46(3), p.315 - 323, 1973/03
Times Cited Count：16no abstracts in English
