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Fukaya, Yuji; Okita, Shoichiro; Kanda, Shun*; Goto, Masaki*; Nakajima, Kunihiro*; Sakon, Atsushi*; Sano, Tadafumi*; Hashimoto, Kengo*; Takahashi, Yoshiyuki*; Unesaki, Hironobu*
KURNS Progress Report 2021, P. 101, 2022/07
The Japan Atomic Energy Agency (JAEA) started the Research and Development (R&D) to improve nuclear prediction techniques for High Temperature Gas-cooled Reactors (HTGRs) in 2018. The objectives are to intro-duce the generalized bias factor method to avoid full mock-up experiment for the first commercial HTGR and to improve neutron instrumentation system by virtue of the particular characteristics due to a graphite moderation system. For this end, we composed B7/4"G2/8"p8EU(3)+3/8"p38EU in the B-rack of Kyoto University Critical Assembly (KUCA) in 2021.
Okita, Shoichiro; Fukaya, Yuji; Sakon, Atsushi*; Sano, Tadafumi*; Takahashi, Yoshiyuki*; Unesaki, Hironobu*
Proceedings of International Conference on Physics of Reactors 2022 (PHYSOR 2022) (Internet), 9 Pages, 2022/05
Okita, Shoichiro; Fukaya, Yuji; Sakon, Atsushi*; Sano, Tadafumi*; Takahashi, Yoshiyuki*; Unesaki, Hironobu*
Nuclear Science and Engineering, 7 Pages, 2022/00
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)Takahashi, Yoshiyuki*; Koizumi, Mitsuo
Nihon Genshiryoku Gakkai-Shi ATOMO
, 62(8), p.452 - 456, 2020/08
no abstracts in English
Am neutron capture and total cross sections with ANNRI at J-PARCKimura, Atsushi; Nakamura, Shoji; Terada, Kazushi*; Nakao, Taro*; Mizuyama, Kazuhito*; Iwamoto, Nobuyuki; Iwamoto, Osamu; Harada, Hideo; Katabuchi, Tatsuya*; Igashira, Masayuki*; et al.
Journal of Nuclear Science and Technology, 56(6), p.479 - 492, 2019/06
Times Cited Count：10 Percentile：80.76(Nuclear Science & Technology)
Am with ANNRI at J-PARCTerada, Kazushi*; Kimura, Atsushi; Nakao, Taro*; Nakamura, Shoji; Mizuyama, Kazuhito*; Iwamoto, Nobuyuki; Iwamoto, Osamu; Harada, Hideo; Katabuchi, Tatsuya*; Igashira, Masayuki*; et al.
Journal of Nuclear Science and Technology, 55(10), p.1198 - 1211, 2018/10
Times Cited Count：15 Percentile：87.82(Nuclear Science & Technology)Kitatani, Fumito; Tsuchiya, Harufumi; Toh, Yosuke; Hori, Junichi*; Sano, Tadafumi*; Takahashi, Yoshiyuki*; Nakajima, Ken*
KURRI Progress Report 2017, P. 99, 2018/08
Pyeon, C. H.*; Vu, T. M.*; Yamanaka, Masao*; Sugawara, Takanori; Iwamoto, Hiroki; Nishihara, Kenji; Kim, S. H.*; Takahashi, Yoshiyuki*; Nakajima, Ken*; Tsujimoto, Kazufumi
Journal of Nuclear Science and Technology, 55(2), p.190 - 198, 2018/02
Times Cited Count：14 Percentile：86.18(Nuclear Science & Technology)At the Kyoto University Critical Assembly, a series of reaction rate experiments is conducted on the accelerator-driven system (ADS) with spallation neutrons generated by the combined use of 100 MeV protons and a lead and bismuth target in the subcritical state. The reaction rates are measured by the foil activation method to obtain neutron spectrum information on ADS. Numerical calculations are performed with MCNP6.1 and JENDL/HE-2007 for high-energy protons and spallation process, JENDL-4.0 for transport and JENDL/D-99 for reaction rates. The reaction rates depend on subcriticality is revealed by the accuracy of the C/E (calculation/experiment) values. Nonetheless, the accuracy of the reaction rates at high-energy thresholds remains an important issue in the fixed-source calculations.
Harada, Hideo; Iwamoto, Osamu; Iwamoto, Nobuyuki; Kimura, Atsushi; Terada, Kazushi; Nakao, Taro; Nakamura, Shoji; Mizuyama, Kazuhito; Igashira, Masayuki*; Katabuchi, Tatsuya*; et al.
EPJ Web of Conferences, 146, p.11001_1 - 11001_6, 2017/09
Times Cited Count：2 Percentile：80.37Sano, Tadafumi*; Hori, Junichi*; Takahashi, Yoshiyuki*; Yashima, Hiroshi*; Lee, J.*; Harada, Hideo
EPJ Web of Conferences, 146, p.03031_1 - 03031_3, 2017/09
Times Cited Count：2 Percentile：80.37Pyeon, C. H.*; Fujimoto, Atsushi*; Sugawara, Takanori; Iwamoto, Hiroki; Nishihara, Kenji; Takahashi, Yoshiyuki*; Nakajima, Ken*; Tsujimoto, Kazufumi
Nuclear Science and Engineering, 185(3), p.460 - 472, 2017/03
Times Cited Count：11 Percentile：76.91(Nuclear Science & Technology)Sensitivity and uncertainty analyses of lead (Pb) isotope cross sections are conducted with the use of sample reactivity experiments at the Kyoto University Critical Assembly (KUCA). With the combined use of the SRAC2006 and MARBLE code systems, attempts are made to precisely examine the contributions of the reactions and energy regions of Pb isotope cross sections to reactivity based on the covariance data of JENDL-4.0. Moreover, the effect of decreasing uncertainty is discussed in terms of the accuracy of sample reactivity by applying the cross section adjustment method to the uncertainty analyses. From the results of the sensitivity and uncertainty analyses, the reliability of Pb isotope cross sections, such as the Pb isotope covariance data of JENDL-4.0, is compared with the JENDL-3.3, ENDF/B-VII.0, and JEFF-3.1 libraries.
(Al,Ga)
O
scintillator Compton camera mounted on an unmanned helicopterShikaze, Yoshiaki; Nishizawa, Yukiyasu; Sanada, Yukihisa; Torii, Tatsuo; Jiang, J.*; Shimazoe, Kenji*; Takahashi, Hiroyuki*; Yoshino, Masao*; Ito, Shigeki*; Endo, Takanori*; et al.
Journal of Nuclear Science and Technology, 53(12), p.1907 - 1918, 2016/12
Times Cited Count：30 Percentile：95.82(Nuclear Science & Technology)The Compton camera was improved for use with the unmanned helicopter. Increase of the scintillator array from 4
4 to 88 and expanse of the distance between the two layers contributed to the improvements of detection efficiency and angular resolution, respectively. Measurements were performed over the riverbed of the Ukedo river of Namie town in Fukushima Prefecture. By programming of flight path and speed, the areas of 65 m 60 m and 65 m 180 m were measured during about 20 and 30 minutes, respectively. By the analysis the air dose rate maps at 1 m height were obtained precisely with the angular resolution corresponding to the position resolution of about 10 m from 10 m height. Hovering flights were executed over the hot spot areas for 10-20 minutes at 5-20 m height. By using the reconstruction software the 
-ray images including the hot spots were obtained with the angular resolution same as that evaluated in the laboratory (about 10
).
Nakamura, Shoji; Terada, Kazushi; Shibahara, Yuji*; Uehara, Akihiro*; Fujii, Toshiyuki*; Sano, Tadafumi*; Takahashi, Yoshiyuki*; Hori, Junichi*
KURRI Progress Report 2015, P. 67, 2016/08
The activation measurements of Np-237 were performed with neutron sources at KURRI-Linac. It was found that activation measurements supported the evaluated cross-section data of JENDL-4.0.
Nakamura, Shoji; Terada, Kazushi; Takahashi, Yoshiyuki*; Sano, Tadafumi*; Hori, Junichi*
KURRI Progress Report 2015, P. 69, 2016/08
Neutron capture cross section measurements has been conducted for Minor Actinides (MAs) under the research project entitled by "Research and development for Accuracy Improvement of neutron nuclear data on Minor ACtinides (AIMAC)". The present work selected two americium isotopes, Am and Am, were selected, and measurements were carried out by an activation method with neutron sources at KURRI-Linac. It was found that the neutron flux at the target positon was of the order of 10
(n/cm
s). The reaction rates of Am and Am were obtained by 
- and -ray measurements of the irradiated Am samples.
Np using variable neutron field at KURRI-LINACTakahashi, Yoshiyuki*; Hori, Junichi*; Sano, Tadafumi*; Yagi, Takahiro*; Yashima, Hiroshi*; Pyeon, C. H.*; Nakamura, Shoji; Harada, Hideo
Proceedings of International Conference on the Physics of Reactors; Unifying Theory and Experiments in the 21st Century (PHYSOR 2016) (USB Flash Drive), p.645 - 652, 2016/05
For the reduction of radioactive toxicities, feasibility study of nuclear transmutation of minor actinides (MAs) and long-lived fission products (LLFPs) by utilizing innovative nuclear reactor system (i.e. fast breeder reactors and accelerator-driven systems) has been actively conducted. To design these nuclear reactor systems, the accurate nuclear data are required. Therefore, to obtain more accurate nuclear data, the project entitled as "Research and development for Accuracy Improvement of neutron nuclear data on Minor ACtinides(AIMAC)" has been started as one of the "Innovative Nuclear Research and Development Program". In a part of this project, the nuclear data of MAs are verified in the variable neutron spectra field at Kyoto University Research Reactor Institute-LINear ACcelerator (KURRI-LINAC) and Kyoto University Critical Assembly (KUCA). And the differential TOF data is cross-checked with an integral data for the validation of Np, Am, and Am. In this summary, the results of reaction rate of neutron capture cross section of Np are reported as an example in the study.
Pyeon, C. H.*; Fujimoto, Atsushi*; Sugawara, Takanori; Yagi, Takahiro*; Iwamoto, Hiroki; Nishihara, Kenji; Takahashi, Yoshiyuki*; Nakajima, Ken*; Tsujimoto, Kazufumi
Journal of Nuclear Science and Technology, 53(4), p.602 - 612, 2016/04
Times Cited Count：19 Percentile：89.1(Nuclear Science & Technology)Sample reactivity experiments on the uncertainty analyses of Pb nuclear data are carried out by substituting Al plates for Pb ones at the Kyoto University Critical Assembly, as part of basic research on Pb-Bi for the coolant. Numerical simulations of sample reactivity experiments are performed with the Monte Carlo calculation code MCNP6.1 together with four nuclear data libraries JENDL-3.3, JENDL-4.0, ENDF/B-VII.0 and JEFF-3.1, to examine the accuracy of cross-section uncertainties of Pb isotopes by comparing measured and calculated sample reactivities. A library update from JENDL-3.3 to JENDL-4.0 is demonstrated by the fact that the difference between Pb isotopes of the two JENDL libraries is dominant in the comparative study, through the experimental analyses of sample reactivity by the MCNP approach. In addition, JENDL-4.0 reveals a slight difference from ENDF/B-VII.0 in all Pb isotopes and 
Al, and from JEFF-3.1 in 
U and Al.
pellets for Mo-99 production, 2Nishikata, Kaori; Ishida, Takuya; Yonekawa, Minoru; Kato, Yoshiaki; Kurosawa, Makoto; Kimura, Akihiro; Matsui, Yoshinori; Tsuchiya, Kunihiko; Sano, Tadafumi*; Fujihara, Yasuyuki*; et al.
KURRI Progress Report 2014, P. 109, 2015/07
As one of effective applications of the Japan Materials Testing Reactor (JMTR), JAEA has a plan to produce 
Mo by (n,) method ((n,)Mo production), a parent nuclide of 
Tc. In this study, preliminary irradiation test was carried out with the high-density molybdenum trioxide (MoO) pellets in the hydraulic conveyer (HYD) of the Kyoto University Research Reactor (KUR) and the Tc solution extracted from Mo was evaluated. After the irradiation test of the high-density MoO pellets in the KUR, Tc was extracted from the Mo solution and the recovery rate of Tc achieved the target values. The Tc solution also got the value that satisfied the standard value for Tc radiopharmaceutical products by the solvent extraction method.
Takeuchi, Tomoaki; Yamamoto, Keiichi; Otsuka, Noriaki; Shibata, Hiroshi; Shibata, Akira; Takemoto, Noriyuki; Tsuchiya, Kunihiko; Sano, Tadafumi*; Unesaki, Hironobu*; Fujihara, Yasuyuki*; et al.
KURRI Progress Report 2014, P. 108, 2015/07
Investigation of a relation between output power and brightness of Cherenkov light of a specific fuel element at KUR by a CCD camera was performed due to a development of a real-time in-core measurement technique using Cherenkov light. The results indicate that the inhomogeneous distribution of output power and the shadow of the control-rod guide tubes and the other irradiation equipment have significant effects on the brightness of the Cherenkov light. These effects could be suppressed by using a number of cameras located at various positions.
Harada, Hideo; Iwamoto, Osamu; Iwamoto, Nobuyuki; Kimura, Atsushi; Terada, Kazushi; Nakao, Taro; Nakamura, Shoji; Mizuyama, Kazuhito; Igashira, Masayuki*; Katabuchi, Tatsuya*; et al.
EPJ Web of Conferences, 93, p.06001_1 - 06001_5, 2015/05
Times Cited Count：4 Percentile：85.76Improvement of accuracy of neutron nuclear data for minor actinides (MAs) and long-lived fission products (LLFPs) is required for developing innovative nuclear system transmuting these nuclei. In order to meet the requirement, the project entitled as "Research and development for Accuracy Improvement of neutron nuclear data on Minor ACtinides (AIMAC)" has been started as one of the "Innovative Nuclear Research and Development Program" at October 2013. The AIMAC project team is composed of researchers in four different fields: differential nuclear data measurement, integral nuclear data measurement, nuclear chemistry, and nuclear data evaluation. By integrating all of the forefront knowledge and techniques in these fields, the team aims at improving the accuracy of the data. The background, overall plan, and recent progress of the AIMAC project will be reviewed.
Otsuka, Noriaki; Takeuchi, Tomoaki; Yamamoto, Keiichi; Shibata, Akira; Kimura, Nobuaki; Takemoto, Noriyuki; Tanimoto, Masataka; Tsuchiya, Kunihiko; Sano, Tadafumi*; Unesaki, Hironobu*; et al.
KURRI Progress Report 2013, P. 215, 2014/10
Investigation of a relation between reactor power and brightness of Cherenkov light at Kyoto University Research reactor (KUR) by a CCD camera was performed due to a development of a real-time in-core measurement technique using Cherenkov light. Analyzing the brightness value of individual RGB color component at each pixel, some of the G and B brightness values reached the maximum value of 8-bit binary number, i.e. 255, above about 2-3 MW. Therefore, we corrected the G and B brightness values by the R signals whose brightness value did not saturate even at 5 MW, the maximum reactor power of KUR. Then, the total brightness value was in proportion to the reactor power after the correction. These results indicate the reactor power can be estimated by the observation of Cherenkov light.
