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Motome, Yuiko; Agake, Toshiki; Yanagisawa, Hiroshi
JAEA-Technology 2024-015, 30 Pages, 2025/01
The tables for calibration of control rods were verified, which is used positive period method and improved rod drop method of periodic inspection at Nuclear Safety Research Reactor (NSRR). Those tables are "DOUBLING TIME-REACTIVITY" and "DECAY OF NEUTRON FLUX AFTER INSTANTANEOUS REDUCTION OF REACTIVITY". They are prepared around 1975. Since those tables do not clearly express source of values and records of data used in calculations, the authors verified those tables again. For the verification, the tables were reproduced as follows. For the positive period method, the relationship between the period and reactivity was analytically evaluated by using the inhour equation with NSRR's parameters. For the improved rod drop method, the ratios of neutron flux after the rod drop with parameters of negative reactivities was calculated using the EUREKA- 2 code. As a result, the values described in the tables well agree with those by the present evaluation because it is confirmed that standard deviations of the differences in the value by between the present evaluation and the tables are less than 0.035%. For this reason, it is verified that these tables are valid in the practical use for NSRR operations.
Fujihara, Masayoshi; Okabe, Hirotaka*; Koda, Akihiro*
Interactions (Internet), 245(1), p.13_1 - 13_6, 2024/12
Quantum states are difficult to observe experimentally. In addition, ideal model materials have not been found for some of the lattice systems in which exotic quantum states are predicted to be realized. Numerous candidates for low-dimensional quantum magnets are hidden in copper minerals, and the number of candidates is increasing every year. We succeeded to synthesize seven copper minerals by imitating the environment where they are discovered and reported their quantum states. The properties of pulsed muons are very suitable for investigating the spin state of artificial copper minerals.
Emura, Yuki; Takai, Toshihide; Kikuchi, Shin; Kamiyama, Kenji; Yamano, Hidemasa; Yokoyama, Hiroki*; Sakamoto, Kan*
Journal of Nuclear Science and Technology, 61(7), p.911 - 920, 2024/07
Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)Ishida, Shinya; Uchibori, Akihiro; Okano, Yasushi
Dai-28-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (Internet), 4 Pages, 2024/06
no abstracts in English
Takahashi, Rieko*; Taniguchi, Naoki
Zairyo To Kankyo, 73(6), p.153 - 163, 2024/06
Carbon steel is one of the candidate materials for overpacks in geological disposal of high-level radioactive waste, and is known to susceptible to stress corrosion cracking(SCC) depending on the condition in carbonate environment. In order to understand the influence of temperature on the SCC susceptibility of carbon steel, slow strain rate test (SSRT) of rolled steel were performed in NaHCO aqueous solution with varying temperature in the range of 303-393K for conditions of 0.1-0.5 mol/dm
, which is assumed to be the upper limit of carbonate concentration in groundwater in a geological disposal environment. As the results, no obvious influence of temperature on mechanical properties such as fracture strain ratio and reduction area ratio were observed, but SCC susceptibility based on SCC fracture ratio increased at relatively low temperatures of 303K and 323K. It was suggested that the reason for the higher SCC sensitivity at lower temperatures was due to slower repassivation at lower temperatures. Regarding the type of SCC, intergranular SCC was dominant at low temperatures and tended to transition to intergranular SCC at higher temperatures. Transgranular SCC tended to be observed at lower potentials than those at which intergranular SCC was observed.
Ishida, Shinya; Fukano, Yoshitaka; Tobita, Yoshiharu; Okano, Yasushi
Journal of Nuclear Science and Technology, 61(5), p.582 - 594, 2024/05
Times Cited Count:1 Percentile:34.39(Nuclear Science & Technology)Deng, Y.*; Watanabe, Yukinobu*; Manabe, Seiya*; Liao, W.*; Hashimoto, Masanori*; Abe, Shinichiro; Tampo, Motonobu*; Miyake, Yasuhiro*
IEEE Transactions on Nuclear Science, 71(4, Part 2), p.912 - 920, 2024/04
Times Cited Count:0 Percentile:0.00(Engineering, Electrical & Electronic)With the miniaturization of semiconductors and the decrease in operating voltage, there is a growing interest and discussion in whether the muons in cosmic rays may be the source of single event upsets (SEUs). In the case of neutron-induced SEUs, it was reported that the irradiation side has the impact on SEU cross sections. Here, to investigate the impact of irradiation direction on muon-induced SEUs, we have measured and simulate muon-induced SEUs in 65-nm bulk SRAMs with different muon irradiation directions. It was found that the peak SEU cross section for the package side irradiation is about twice large as that for the board side irradiation. We also revealed that the difference in observed SEU cross sections between the package side and the board side irradiation is caused by differences in energy straggling due to changes in penetration depth depending on the incident direction.
Yamada, Kazuo*; Hokora, Hideyuki*; Maruyama, Ippei*; Aihara, Haruka; Tomita, Sayuri*; Tojo, Yasumasa*; Shibuya, Kazutoshi*; Hosokawa, Yoshifumi*; Igarashi, Go*; Koma, Yoshikazu
Proceedings of Waste Management Symposia 2024 (WM2024) (Internet), 7 Pages, 2024/03
Honda, Maki; Martschini, M.*; Marchhart, O.*; Steier, P.*; Golser, R.*; Sakaguchi, Aya*
Hoshasen (Internet), 48(4), p.130 - 136, 2024/02
Strontium-90 (Sr, 28.9 years) is a key fission product nuclide in internal dose assessment because it accumulates in bones and teeth in the body, causing health problems. Therefore, it is essential to know the distribution of
Sr in the environment and its temporal variation (
Sr enrichment in biota), which requires efficient analysis of many environmental samples. An analysis of environmental samples with known
Sr concentrations conducted with the 3 MV AMS facility (VERA: Vienna Environmental Research Accelerator) at the University of Vienna, Austria, towards the practical application of
Sr AMS, the results of which are detailed in this paper. In this study, the validity of the AMS method was demonstrated by analyzing environmental samples with known
Sr concentrations (IAEA-447, IAEA-A-12, and IAEA-TEL-2015-03 sample 5: 1 dry-g each). The chemical separation developed in this study takes approximately two days and is a more straightforward procedure than conventional
-ray detection methods. The
Sr measurements were conducted on the AMS system combined with the Ion Laser InterAction Mass Spectrometry (ILIAMS) system. The AMS method achieved a limit of detection
0.1 mBq (
1.3
10
atoms) for
Sr, which is 1/30th of typical
-ray detection. As a result of the lower detection limit, the AMS method allows
Sr quantification with smaller sample volumes. For example, a Japanese freshwater sample with a
Sr concentration of 4 mBq/L requires a sample volume of 5 liter
Koarai, Kazuma; Matsueda, Makoto; Aoki, Jo; Terashima, Motoki
KEK Proceedings 2023-2, p.155 - 160, 2023/11
In this presentation, we report the results of the application of the Y-separation method using DGA resin to the determination of Sr in human teeth and seawater fish bones.
Yanagisawa, Hiroshi; Umeda, Miki; Motome, Yuiko; Murao, Hiroyuki
Proceedings of 12th International Conference on Nuclear Criticality Safety (ICNC2023) (Internet), 10 Pages, 2023/10
The benchmark analyses on the TRIGA reactor of the IEU-COMP-THERM-013 (ICT-013) in the ICSBEP handbook using the MVP version 3 code were carried out with the Japanese, US and European nuclear data libraries, including JENDL-5. The analyses on effective neutron multiplication factors (k's) were also performed for another TRIGA reactor defined in the ICT-003 as well as the ICT-013. As a result, it is confirmed that the calculated k
's vary in the range of 0.8% with the libraries. The results also suggest that there might be unknown bias in the ICT-013 for the calculated k
's. For the analyses on the control rod worths of the ICT-013, it is confirmed that differences in the worths among the libraries become smaller than those in k
's. Most of the errors involved in k
's are considered to be cancelled in the calculation of the worths since the worths are obtained by subtraction of the reciprocals of two sorts of k
's. The differences in the worths by between the benchmark and alternative methods defined in the ICT-013 were tried to be examined from the aspect of the differences in horizontal flux distributions by between those methods. It is confirmed that the differences in the worths for two shim control rods, which are fully withdrawn at a delayed critical state, are well understood by that attempt, but on the other hand the differences are not sufficiently explained for a regulating control rod, which is partially inserted to attain delayed criticality.
Koarai, Kazuma
Hosha Kagaku, (47), p.24 - 27, 2023/03
Ca-based tissues, such as teeth and bones, are called hard tissues. Sr is incorporated into the tooth during calcification. Once incorporated, it remains until the tooth falls out. Therefore, Sr in teeth recorded
Sr contamination by the 1F accident in the environment during the formation period. The article presents current research findings.
Yanagisawa, Hiroshi; Umeda, Miki; Motome, Yuiko; Murao, Hiroyuki
JAEA-Technology 2022-030, 80 Pages, 2023/02
Nuclear criticality benchmark analyses were carried out for TRIGA-type reactor systems in which uranium-zirconium hydride fuel rods are loaded by using the continuous-energy Monte Carlo code MVP with the evaluated nuclear data library JENDL-5. The analyses cover two sorts of benchmark data, the IEU-COMP-THERM-003 and IEU-COMP-THERM-013 in the International Criticality Safety Benchmark Evaluation Project (ICSBEP) Handbook, and effective neutron multiplication factors, reactivity worths for control rods etc. were calculated by JENDL-5 in comparison with those by the previous version of JENDL. As the results, it was confirmed that the effective neutron multiplication factors obtained by JENDL-5 were 0.4 to 0.6% greater than those by JENDL-4.0, and that there were no significant differences in the calculated reactivity worths by between JENDL-5 and JENDL-4.0. Those results are considered to be helpful for the confirmation of calculation accuracy in the analyses on NSRR control rod worths, which are planned in the future.
Fujihara, Masayoshi; Hagihara, Masato; Morita, Katsuhiro*; Murai, Naoki; Koda, Akihiro*; Okabe, Hirotaka*; Mitsuda, Setsuo*
Physical Review B, 107(5), p.054435_1 - 054435_8, 2023/02
Times Cited Count:1 Percentile:0.00(Materials Science, Multidisciplinary)The = 1/2 Heisenberg linear chain antiferromagnet is the simplest spin model; nevertheless it serves as a platform for various quantum many-body phenomena. Here, we report the magnetic behavior of a quasi-one-dimensional antiferromagnet KCuPO
H
O. A long-range commensurate antiferromagnetic order with ordered moment 0.31(1)
per spin occurs at
= 11.7(1) K. Above
, the inelastic neutron excitation is characterized by a two spinon continuum. The intrachain interaction
and interchain interaction
are estimated to be 172 K and 4.25(4) K, respectively; thus the ratio of the
/
= 0.0247(3). At lower energies, below
, a spin gap is observed in the dispersive excitations. These results are consistent with characteristics observed in weakly interacting
= 1/2 Heisenberg chain system.
Yamada, Kazuo*; Tojo, Yasumasa*; Aihara, Haruka; Tomita, Sayuri*; Hokora, Hideyuki*; Shibuya, Kazutoshi*; Koma, Yoshikazu; Igarashi, Go*; Hosokawa, Yoshifumi*; Maruyama, Ippei*
Proceedings of Waste Management Symposia 2023 (WM2023) (Internet), 12 Pages, 2023/02
Zhang, T.*; Morita, Koji*; Liu, X.*; Liu, W.*; Kamiyama, Kenji
Annals of Nuclear Energy, 179, p.109389_1 - 109389_10, 2022/12
Times Cited Count:3 Percentile:34.71(Nuclear Science & Technology)Honda, Maki
Journal of the Mass Spectrometry Society of Japan, 70(4), p.282 - 283, 2022/12
The development of measurement and chemical separation techniques in the accelerator mass spectrometry (AMS) method has enabled highly sensitive analysis of Pu (half-life 8.1
10
years),
Fe (half-life 2.62
10
years), and
Sr (half-life 28.9 years) in AMS. For example, the study analyzing
Pu in ferromanganese crust samples successfully quantified
Pu from outside the solar system, which had been hidden by
Pu from nuclear tests. Furthermore, the research has revealed that
Pu is produced in neutron star mergers, etc., leading to unraveling the production sites where the heavy elements originate. This topic highlights the frontline of studies on
Pu,
Fe, and
Sr utilizing AMS.
Fujihara, Masayoshi; Jeschke, H. O.*; Morita, Katsuhiro*; Kuwai, Tomohiko*; Koda, Akihiro*; Okabe, Hirotaka*; Matsuo, Akira*; Kindo, Koichi*; Mitsuda, Setsuo*
Physical Review Materials (Internet), 6(11), p.114408_1 - 114408_8, 2022/11
Times Cited Count:2 Percentile:7.18(Materials Science, Multidisciplinary) = 1/2 Heisenberg
-
chain antiferromagnets have been investigated extensively due to their exotic magnetic states. Here, we report the magnetic behavior of birchite Cd
Cu
(PO
)
SO
5H
O and its effective spin model. Experimental studies by magnetic susceptibility, magnetization, heat capacity, and
SR measurements indicate the absence of long-range order down to 0.4 K. Theoretical studies reveal that birchite is a model compound for the
-
antiferromagnetic chain: the intrachain interactions
and
are antiferromagnetic and their magnitude is about 100 times larger than the interchain interactions. The magnitude of
is two to three times larger than that of
, thus the spin gap is expected to be only a few percent of that of
. The temperature dependence of the specific heat shows a broad peak at about 1 K (
0.036
), which suggests the presence of a spin gap.
Takatsuka, Daichi*; Morita, Koji*; Liu, W.*; Zhang, T.*; Nakamura, Takeshi*; Kamiyama, Kenji
Proceedings of 12th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS12) (Internet), 10 Pages, 2022/10
Ito, Takashi
Meson, (56), p.21 - 26, 2022/09
no abstracts in English