Real-time inversion of radioactive source distribution using air dose rate measurements via least absolute shrinkage and selection operator method

Shi, W.*; Machida, Masahiko; Okamoto, Koji*; Luo, X.*; Feng, W.*; Liu, X.*

Reliability Engineering & System Safety, 272, Part1, p.112538_1 - 112538_18, 2026/08

http://doi.org/10.1016/j.ress.2026.112538

The reliability of emergency response in severe nuclear accidents critically depends on robust real-time monitoring of radioactive source distributions. However, this safety function is challenged by physical constraints that create monitoring blind spots and by the inadequacy of static methods in tracking dynamic releases. To enhance the reliability and robustness of source term estimation, this study proposes a dynamic reconstruction framework based on LASSO regression with temporal regularization. A sliding-window time-penalty mechanism is introduced, imposing -norm constraints on inter-step source variations to ensure physical continuity. The contribution matrix and measurement vector are normalized to counteract biases from radiation shielding and time-varying intensities. Validation using a two-room model with internal shielding, with PHITS Monte Carlo simulation, demonstrates accurate reconstruction of dynamic sources from remote measurements. Temporal regularization enhances situational awareness by suppressing spatial aliasing: at sliding-window width (no regularization), hotspot locations fluctuate significantly, with quantitative mean absolute error fluctuations at around , whereas yields improved spatial consistency and the fluctuation quantities decrease to the range. Comparative analysis identifies as optimal in balancing accuracy and computational cost. This work establishes a more reliable pathway for dynamic hazard assessment, enabling accurate localization and intensity tracking under challenging conditions. The proposed framework provides a decision-support tool enhancing the resilience and safety of emergency management in nuclear facilities.

Development of phenomenological degradation models for Cr-Coated Zr alloy cladding under high-temperature oxidation conditions

Taniguchi, Yoshinori; Luu, V. N.; Tasaki, Yudai; Udagawa, Yutaka; Katsuyama, Jinya

Annals of Nuclear Energy, 231, p.112177_1 - 112177_16, 2026/06

https://doi.org/10.1016/j.anucene.2026.112177

Negative magnetization phenomenon in TbNiC

Yamamoto, Masataka*; Hidaka, Hiroyuki*; Yanagisawa, Tatsuya*; Tabata, Chihiro; Nakao, Hironori*; Shimomura, Susumu*; Onodera, Hideya*; Amitsuka, Hiroshi*

Journal of the Physical Society of Japan, 95, p.053703_1 - 053703_4, 2026/05

https://doi.org/10.7566/JPSJ.95.053703

A Method for estimating light quenching in inorganic scintillator detectors for radioactive ion beam experiments

Kreinder, B.; Cox, I.*; Grzywacz, R.*; Nishio, Katsuhisa; 24 of others*

Nuclear Instruments and Methods in Physics Research A, 1085, p.171298_1 - 171298_7, 2026/05

https://doi.org/10.1016/j.nima.2026.171298

Microstructural evolution and mechanical hardening of Cr-coated MDA cladding under high-dose Fe ion irradiation

Mohamad, A. B.; Chen, J.*; Ioka, Ikuo*; Suzuki, Eriko; Kondo, Keietsu; Abe, Yosuke; Yamashita, Shinichiro; Okubo, Nariaki; Nemoto, Yoshiyuki; Okada, Yuji*; et al.

Journal of Nuclear Materials, 625, p.156513_1 - 156513_9, 2026/04

https://doi.org/10.1016/j.jnucmat.2026.156513

Simple technique for the preparation of uranium-impregnated porous silica particles and their application as working standard particles for analysis of the safeguards environmental samples

Tomita, Jumpei; Tomita, Ryohei; Suzuki, Daisuke; Yasuda, Kenichiro; Miyamoto, Yutaka

Journal of Nuclear Science and Technology, 63(4), p.443 - 454, 2026/04

https://doi.org/10.1080/00223131.2025.2557376

Magnetic order of Dresselhaus-type antiferromagnet EuIrInGe studied by single crystal neutron diffraction

Tabata, Chihiro; Kaneko, Koji; Nakao, Akiko*; Ohara, Takashi; Matsuda, Tatsuma*; Onuki, Yoshichika*

Journal of the Physical Society of Japan, 95(5), p.053702_1 - 053702_4, 2026/04

https://doi.org/10.7566/JPSJ.95.053702

Reconsideration of numerical model for hydrogen thermal desorption spectra of iron with hydrogen-enhanced strain-induced vacancies

Ebihara, Kenichi; Yamaguchi, Masatake; Itakura, Mitsuhiro

Metallurgical and Materials Transactions A, 57(4), p.1480 - 1489, 2026/04

https://doi.org/10.1007/s11661-026-08146-7

Hydrogen (H) embrittlement is an important issue for steel. The experimental thermal desorption spectra of H from an iron sample containing H-enhanced strain-induced vacancies (Vs) were successfully reproduced by revising a previous numerical model. In the revised model, we adopted concentration variables for Vs and V clusters, which are distinguished by the number of trapped H atoms. This revision eliminated the assumption of V and V cluster migration, required in the original model. Simulation results of the revised model revealed that the spike-like desorption on the peak attributed to Vs and V clusters in the spectra simulated by the original model was an artifact caused by the assumption. In addition, it was suggested that V clusters can exist other than Vs in the specimens after deformation with H charging. It is considered that the revised model is a useful framework for studying Vs and V clusters under H-affected conditions.

Field-induced antiferromagnetic transition in CeIrIn

Tokunaga, Yo; Suzuki, Michito*; Krmer, S.*; Sakai, Hironori; Kambe, Shinsaku; Harima, Hisatomo*; Aoki, Dai*; Horvati, M.*; Sheikin, I.*

Physical Review B, 113(14), p.L140406_1 - L140406_7, 2026/04

https://doi.org/10.1103/8khb-593t

Low-energy electric and magnetic dipole excitations in Er

Shizuma, Toshiyuki*; Omer, M.; Hajima, Ryoichi*; Koizumi, Mitsuo; Takahashi, Tone; Tsunoda, Yusuke*; Otsuka, Takaharu*

Physical Review C, 113(4), p.044325_1 - 044325_9, 2026/04

https://doi.org/10.1103/zwx8-fpdh