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Ishitsuka, Etsuo; Nagasumi, Satoru; Hasegawa, Toshinari; Kawai, Hiromi*; Wakisaka, Shinji*; Nagase, Sota*; Nakamura, Kento*; Yaguchi, Hiroki*; Ishii, Toshiaki; Nakano, Yumi*; et al.
JAEA-Technology 2024-008, 23 Pages, 2024/07
JAEA-Technology-2024-008.pdf:1.69MB
Five people from three universities participated in the 2023 summer holiday practical training with the theme of "Technical development on HTTR". The participants practiced the analysis of HTTR core, the analysis of behavior on loss of forced cooling test, the analysis of Iodine deposition behavior in primary cooling system and the feasibility study of energy storage system for HTGRs. In the questionnaire after this training, there were impressions such as that it was useful as a work experience and some students found it useful for their own research. These impressions suggest that this training was generally evaluated as good.
Ishitsuka, Etsuo; Ho, H. Q.; Kitagawa, Kanta*; Fukuda, Takahito*; Ito, Ryo*; Nemoto, Masaya*; Kusunoki, Hayato*; Nomura, Takuro*; Nagase, Sota*; Hashimoto, Haruki*; et al.
JAEA-Technology 2023-013, 19 Pages, 2023/06
JAEA-Technology-2023-013.pdf:1.75MB
Eight people from five universities participated in the 2022 summer holiday practical training with the theme of "Technical development on HTTR". The participants practiced the feasibility study for nuclear battery, the burn-up analysis of HTTR core, the feasibility study for 
Cf production, the analysis of behavior on loss of forced cooling test, and the thermal-hydraulic analysis near reactor pressure vessel. In the questionnaire after this training, there were impressions such as that it was useful as a work experience, that some students found it useful for their own research, and that discussion with other university students was a good experience. These impressions suggest that this training was generally evaluated as good.
Ikeda, Reiji*; Ho, H. Q.; Nagasumi, Satoru; Ishii, Toshiaki; Hamamoto, Shimpei; Nakano, Yumi*; Ishitsuka, Etsuo; Fujimoto, Nozomu*
JAEA-Technology 2021-015, 32 Pages, 2021/09
JAEA-Technology-2021-015.pdf:2.74MB
Burnup calculation of the HTTR considering temperature distribution and detailed burning regions was carried out using MVP-BURN code. The results show that the difference in k
, as well as the difference in average density of some main isotopes, is insignificant between the cases of uniform temperature and detailed temperature distribution. However, the difference in local density is noticeable, being 6% and 8% for 
U and 
Pu, respectively, and even 30% for the burnable poison 
B. Regarding the division of burning regions to more detail, the change of k is also small of 0.6%
k/k or less. The small burning region gives a detailed distribution of isotopes such as U, Pu, and B. As a result, the effect of graphite reflector and the burnup behavior could be evaluated more clearly compared with the previous study.
Fujimoto, Nozomu*; Fukuda, Kodai*; Honda, Yuki*; Tochio, Daisuke; Ho, H. Q.; Nagasumi, Satoru; Ishii, Toshiaki; Hamamoto, Shimpei; Nakano, Yumi*; Ishitsuka, Etsuo
JAEA-Technology 2021-008, 23 Pages, 2021/06
JAEA-Technology-2021-008.pdf:2.62MB
The effect of mesh division around the burnable poison rod on the burnup calculation of the HTTR core was investigated using the SRAC code system. As a result, the mesh division inside the burnable poison rod does not have a large effect on the burnup calculation, and the effective multiplication factor is closer to the measured value than the conventional calculation by dividing the graphite region around the burnable poison rod into a mesh. It became clear that the mesh division of the graphite region around the burnable poison rod is important for more appropriately evaluating the burnup behavior of the HTTR core..
Matsuya, Yusuke; Nakano, Toshiaki*; Kai, Takeshi; Shikazono, Naoya*; Akamatsu, Ken*; Yoshii, Yuji*; Sato, Tatsuhiko
International Journal of Molecular Sciences (Internet), 21(5), p.1701_1 - 1701_13, 2020/03
Times Cited Count：15 Percentile：65.49(Biochemistry & Molecular Biology)Among various DNA damage induced after irradiation, clustered damage composed of at least two vicinal lesions within from 10 to 20 base pairs is recognized as fatal damage to human tissue. Such clustered damage yields have been evaluated by means of computational approaches; however, the simulation validity has not been sufficiently made yet. Meanwhile, the experimental technique to detect clustered DNA damage has been evolved in the recent decades, so both approaches with simulation and experiment get used to be available for investigating clustered damage recently. In this study, we have developed a simple model for estimating clustered damage yield based on the spatial density of ionization and electronic excitation events obtained by the PHITS code, and compared the computational results to the experimental clustered damage coupled with base damage (BD) measured by gel electrophoresis and atomic force microscopy. The computational results agreed well with experimental fractions of clustered damage of strand breaks (SB) and BD, when the yield ratio of BD/SSB is assumed to be 1.3. From the comparison of complex DNA double-strand break coupled with BDs between simulation and experimental data, it was suggested that aggregation degree of the events along electron track reflects the complexity of DNA damage. The resent simulation enables to quantify the type of clustered damage which cannot be measured in in vitro experiment, which succeeded in interpreting the experimental detection efficiency for clustered BD.
Takeuchi, Tomoaki; Nakano, Hiroko; Uehara, Toshiaki; Tsuchiya, Kunihiko
Nuclear Materials and Energy (Internet), 9, p.451 - 454, 2016/12
Times Cited Count：1 Percentile：10.51(Nuclear Science & Technology)no abstracts in English
Takeuchi, Tomoaki; Nakano, Hiroko; Uehara, Toshiaki; Tsuchiya, Kunihiko
Proceedings of International Conference on Asia-Pacific Conference on Fracture and Strength 2016 (APCFS 2016) (USB Flash Drive), p.95 - 96, 2016/09
Monitoring system of the nuclear power plants during a severe accident has increased in importance after the accident at the Fukushima Dai-ichi Nuclear Power Plant. As part of the system, the development of mineral insulated (MI) cables available under the normal and severe environments was started. In this study, in order to investigate mechanical integrity of MI cables in reactor coolant condition, effects of dissolved oxygen on fracture properties of the sheath materials of the MI cables in high temperature and pressure pure water were evaluated. As the sheath materials, AISI 304 and 316 stainless steels were selected and slow strain rate testing was performed at 5
10
mm/min in strain rate in pure water at 325
C and 15 MPa. In both the cases of the 304 and 316 steel, from 8500 to 50 ppb dissolved oxygen (DO), fully ductile fracture surfaces were observed and tensile strength and breaking elongation were almost the same values. However, at 10 and 1 ppb DO, brittle fracture surfaces were observed around the outer edge of the samples, and the tensile strength and breaking elongation decreased. The results indicated the existence of a threshold level of DO for brittle fracture of both the steels at lower than 100 ppb.
Nakano, Hiroko; Uehara, Toshiaki; Takeuchi, Tomoaki; Shibata, Hiroshi; Nakamura, Jinichi; Matsui, Yoshinori; Tsuchiya, Kunihiko
JAEA-Technology 2015-049, 61 Pages, 2016/03
JAEA-Technology-2015-049.pdf:14.7MB
In Japan Atomic Energy Agency, we started a research and development so as to monitor the Nuclear Plant Facilities situations during a severe accident, such as a radiation-resistant monitoring camera under a severe accident, a radiation resistant in-water transmission system for conveying the information in-core and a heat-resistant signal cable. As part of advance in a heat-resistant signal cable, we maintained to ex-core high-temperature and pressure water loop test equipment which can be simulated conditions of BWRs and PWRs for evaluation reliability and property of construction sheath materials. This equipment consists of Autoclave, water conditioning tank, water pump, high-pressure metering pump, preheater, heat exchanger and pure water purification equipment. This report describes the basic design and the results of performance tests of construction machinery and tools of ex-core high-temperature and pressure water loop test equipment.
collisions at 
= 200 and 62.4 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06
Times Cited Count：184 Percentile：99.42(Physics, Nuclear)Transverse momentum distributions and yields for 
, and 
in collisions at = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different collisions. We also present the scaling properties such as 
and 
scaling and discuss the mechanism of the particle production in collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.
and Au+Au collisions at 
= 200 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.
Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04
Times Cited Count：9 Percentile：52.86(Physics, Nuclear)Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to collisions.
Maeda, Yukimoto; Kashimura, Yoichi; Suzuki, Toshiaki; Isozaki, Kazunori; Hoshiba, Hideaki; Kitamura, Ryoichi; Nakano, Tomoyuki; Takamatsu, Misao; Sekine, Takashi
JNC TN9440 2005-001, 540 Pages, 2005/02
JNC-TN9440-2005-001.pdf:8.35MB
Periodic safety review (Review of the activity for safety) which consisted of "Comprehensive evaluation of operation experience" and "Incorporation of the latest technical knowledge" was carried out up to January 2005.
Nakano, Hiroko; Uehara, Toshiaki; Takeuchi, Tomoaki; Shibata, Hiroshi; Nakamura, Jinichi; Matsui, Yoshinori; Tsuchiya, Kunihiko
no journal, ,
no abstracts in English
Shibata, Hiroshi; Onizawa, Tatsuya*; Takeuchi, Tomoaki; Nakano, Hiroko; Uehara, Toshiaki; Takeno, Naofumi*; Miura, Kuniaki*; Tsuchiya, Kunihiko
no journal, ,
no abstracts in English
Matsuya, Yusuke; Kai, Takeshi; Akamatsu, Ken*; Nakano, Toshiaki*; Yoshii, Yuji*; Shikazono, Naoya*; Sato, Tatsuhiko
no journal, ,
Biological effects such as cell death are intrinsically related in track structure and early DNA damage induction. As such, DNA damage estimation based on Monte Carlo simulations is a research topic of worldwide interest. In this study, we developed a model for estimating DNA damage yields based on a general-purpose Monte Carlo code, Particle and Heavy Ion Transport code System (PHITS). By analyzing the spatial patterns of ionization and excitations, the model allows to predict yields of single-strand break, double-strand break and the clustered lesions for electron, proton and carbon ion. As a result, this model successfully reproduced experimental yields of various DNA lesion types in cells for low-LET radiation < about 30 keV/
m. In addition, this model was also found to be sufficient for reproducing the yields measured under dry or hypoxic condition for high-LET ions. This work is expected to contribute on precise understanding of relation between track structure and biological effects.
Tsuchiya, Kunihiko; Takeuchi, Tomoaki; Otsuka, Noriaki; Shibata, Hiroshi; Nakano, Hiroko; Ishida, Takuya; Uehara, Toshiaki; Yamamoto, Keiichi; Saito, Takashi; Nakamura, Jinichi; et al.
no journal, ,
no abstracts in English
