Fast burnup calculation method based on neutron spectrum reconstruction with proper orthogonal decomposition and regression model

Watanabe, Tomoaki; Aizawa, Naoto*; Chiba, Go*; Tada, Kenichi; Yamamoto, Akio*

Proceedings of International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering (M&C 2025) (Internet), 10 Pages, 2025/04

Currently, a major burnup calculation method for the nuclide composition of nuclear fuel conducts neutron transport calculations at each burnup step to account for changes in the neutron spectrum. While this method is highly accurate, the large computational cost of neutron transport calculations can be problematic. Therefore, a fast burnup calculation method based on neutron spectrum reconstruction with the proper orthogonal decomposition (POD) and regression model is investigated. In this method, dimensionality reduction by POD is applied to many neutron fluxes obtained from detailed burnup calculations for various input parameter sets, and regression models are constructed to connect the dimensionality-reduced neutron fluxes and parameters. By substituting arbitrary input parameters to the regression models, the neutron flux is reconstructed and the burnup calculation is performed. This method performs burnup calculations that consider changes in the neutron spectrum based on input conditions without neutron transport calculations. The present method was applied to a PWR UO fuel pin cell model. The results show the nuclide inventory can be calculated with a prediction accuracy within a few percent. In addition, it is found that the calculation error is dominated by the regression models, which implies the further improvement of the regression models leads to improving the accuracy.

Persistent magnetic coherence in magnets

Makiuchi, Takahiko*; Hioki, Tomosato*; Shimizu, Hiroki*; Hoshi, Kojiro*; Elyasi, M.*; Yamamoto, Kei; Yokoi, Naoto*; Serga, A. A.*; Hillebrands, B.*; Bauer, G. E. W.*; et al.

Nature Materials, 23(5), p.627 - 632, 2024/05

https://doi.org/10.1038/s41563-024-01798-z

Behavior estimation focusing on the existing form of hydrogen in sodium in sodium-cooled fast reactors

Hatakeyama, Nozomu*; Miura, Ryuji*; Miyamoto, Naoto*; Miyamoto, Akira*; Ara, Kuniaki; Shimoyama, Kazuhito; Kato, Atsushi; Yamamoto, Tomohiko

Journal of Computer Chemistry, Japan, 21(2), p.61 - 62, 2022/00

https://doi.org/10.2477/jccj.2022-0026

no abstracts in English

Analysis of J-HBC stripper foil for the J-PARC RCS

Yoshimoto, Masahiro; Nakanoya, Takamitsu; Yamazaki, Yoshio; Saha, P. K.; Kinsho, Michikazu; Yamamoto, Shunya*; Okazaki, Hiroyuki*; Taguchi, Tomitsugu*; Yamada, Naoto*; Yamagata, Ryohei*

JPS Conference Proceedings (Internet), 33, p.011019_1 - 011019_7, 2021/03

BB2019-1209.pdf:0.86MB

https://doi.org/10.7566/JPSCP.33.011019

The multi-turn charge-exchange H beam injection scheme with stripper foils is one of the key techniques to achieve a MW-class high power proton beam. The J-PARC RCS adopts Hybrid type Boron-doped Carbon (HBC) stripper foil, which was developed in KEK to improve the lifetime. Indeed, the RCS user operation confirmed that HBC foil has the great advantage of a longer lifetime against high beam irradiation. To examine characteristics of the HBC foils, various beam studies were performed, such as the stripping efficiency measurement and long-term observation with an H beam in the J-PARC RCS, foil analysis using RBS, EDR and PIXE methods, and SEM and TEM observation after the ion beam irradiation in Takasaki Ion Accelerators for Advanced Radiation Application (TIARA) on National Institutes for Quantum and Radiological Science and Technology (QST). Recently, the deposition apparatus for the HBC foils from the KEK Tsukuba-site was relocated to the JAEA Tokai-site, and we started fabrication of new HBC foil in 2017. (The new one fabricated in JAEA we call J-HBC foil.) And, we continue investigations in TIARA with the J-HBC foils. Furthermore, in-depth researches by changing the process parameters of the foil deposition are carried on. Recent results suggest that the amount of the boron doped in the foil is more important parameter than the ratio of the discharge amount of carbon from cathode and anode electrodes. In this presentation, we will report the details of recent analysis of the J-HBC foil.

Localized 5 states in UPdAl and valence crossover in the Vicinity of Heavy-Fermion superconductivity

Metoki, Naoto; Haga, Yoshinori; Yamamoto, Etsuji; Matsuda, Masaaki*

Journal of the Physical Society of Japan, 87(11), p.114712_1 - 114712_9, 2018/11

https://doi.org/10.7566/JPSJ.87.114712

The localized 5 states with 5 () configuration of U ion have been revealed in UPdAl. We found that the low-lying states are the same as PrPdAl flat orbitals with large are stabilized by a two-dimensional CEF potential in the unique crystal structure. The present study involves the valence crossover from tetravalent to trivalent in a series of AnPdAl, demonstrated by lattice and/or transport anomaly as well as many body effects in the vicinity of the boundary. The valence instability plays important role for the unusual heavy fermion superconductivity in NpPdAl.

New muonium HFS measurements at J-PARC/MUSE

Strasser, P.*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; Ito, Takashi; Iwasaki, Masahiko*; et al.

Hyperfine Interactions, 237(1), p.124_1 - 124_9, 2016/12

https://doi.org/10.1007/s10751-016-1331-4

Effect of annealing on crystal and local structures of doped zirconia using experimental and computational methods

Ito, Takanori*; Mori, Masashi*; Inukai, Manabu*; Nitani, Hiroaki*; Yamamoto, Takashi*; Miyanaga, Takashi*; Igawa, Naoki; Kitamura, Naoto*; Ishida, Naoya*; Idemoto, Yasushi*

Journal of Physical Chemistry C, 119(16), p.8447 - 8458, 2015/04

https://doi.org/10.1021/jp5117118

The effects of the annealing process on the crystal and local structures of the doped zirconia were investigated by Rietveld refinements of synchrotron X-ray and neutron diffraction, maximum entropy method (MEM), X-ray absorption spectroscopy (XAS) and first principles calculation (FPC). This study reveals that the crystal structures of the sintered and annealed ((ZrY)O and (ZrScCe)O) are cubic with the space -3 having large atomic displacement parameters (). For the annealed (ZrY)O, the values reduce, and the electrons around the Zr/oxide ion sites gather at the center of each site. On the other hand, the annealed (ZrScCe)O shows the opposite tendency to that of the annealed (ZrY)O.

Metamagnetic transition of itinerant ferromagnet UP under high pressure

Araki, Shingo*; Hayashida, Minami*; Nishiumi, Naoto*; Manabe, Hiroki*; Ikeda, Yoichi*; Kobayashi, Tatsuo*; Murata, Keizo*; Inada, Yoshihiko*; Winiewski, P.*; Aoki, Dai*; et al.

JPS Conference Proceedings (Internet), 3, p.011081_1 - 011081_6, 2014/06

https://doi.org/10.7566/JPSCP.3.011081

Single crystal growth and various electronic states in Yb-based compounds

Hirose, Yusuke*; Yoshiuchi, Shingo*; Nishimura, Naoto*; Sakaguchi, Junya*; Enoki, Kentaro*; Iwakawa, Ken*; Miura, Yasunao*; Sugiyama, Kiyohiro*; Onuki, Yoshichika; Settai, Rikio*; et al.

Journal of the Korean Physical Society, 62(12), p.1858 - 1861, 2013/06

https://doi.org/10.3938/jkps.62.1858

Neutron scattering experiments for the study of in-plane ordered moment in URuSi

Metoki, Naoto; Sakai, Hironori; Yamamoto, Etsuji; Tateiwa, Naoyuki; Matsuda, Tatsuma; Haga, Yoshinori

Journal of the Physical Society of Japan, 82(5), p.055004_1 - 055004_2, 2013/05

https://doi.org/10.7566/JPSJ.82.055004

The hidden order parameter in URuSi remains an open question for this quarter of a century. Many type of models have been proposed. The models predict unusual order parameters such as higher order multipole, dynamical origin, or very recently, "hastatic" order, accompanying Ising quasi-particles. We provide neutron scattering data measured at the wave vector =(003) for the in-plane magnetic component. The existence of the in-plane component in the order of 0.01 or 1010 Bohr magneton has been proposed by a recent theoretical studies. The data were obtained also under magnetic field up to 10 T along the [010] direction in order to reveal a possible type antiferro-quadrupole (AFQ) order at the propagation of =(001) proposed previously. Our data indicate that there is no in-plane magnetic component within the experimental accuracy of 0.004 Bohr magneton. Namely we could not obtain the results which support these theories.