Unveiling the effects of Mn, Cr, Al, and Si on the low-temperature tempering behaviors of high-carbon martensite

Zhang, Y.*; Marusawa, Kenji*; Kudo, Kohei*; Morooka, Satoshi; Gong, W.; Harjo, S.; Miyamoto, Goro*; Furuhara, Tadashi*

Journal of Materials Science & Technology, 275, p.250 - 259, 2026/12

https://doi.org/10.1016/j.jmst.2026.04.015

Probabilistic fracture mechanics benchmarking study of PASCAL-SP code with xLPR code regarding primary water stress corrosion cracking

Mano, Akihiro; Yamaguchi, Yoshihito; Katsuyama, Jinya

International Journal of Pressure Vessels and Piping, 222, p.105792_1 - 105792_11, 2026/08

https://doi.org/10.1016/j.ijpvp.2026.105792

A probabilistic fracture mechanics (PFM) analysis code, PASCAL-SP, has been developed by the Japan Atomic Energy Agency (JAEA) to evaluate the failure probability of piping within nuclear power plants while considering age-related degradations such as stress corrosion cracking and fatigue for both pressurized water reactor and boiling water reactor environments. To strengthen the confidence in the results of PASCAL-SP, a benchmarking study was performed with the PFM analysis code, xLPR, which was developed by the U.S.NRC in collaboration with EPRI. In this benchmarking study, deterministic and probabilistic analyses are performed using common analysis conditions. This paper presents the details of these conditions and comparisons of the results between the two aforementioned codes. Both codes were found to provide nearly the same results in both deterministic and probabilistic analyses for a dissimilar metal weld subjected to primary water stress corrosion cracking.

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.

Prediction of tumor control probability in prostate cancer radiotherapy using a biophysical model incorporating cancer stem cell and hypoxia

Saga, Ryo*; Iwamori, Kenta*; Matsuya, Yusuke; Hosokawa, Yoichiro*

Computers in Biology and Medicine, 211, p.111743_1 - 111743_10, 2026/07

https://doi.org/10.1016/j.compbiomed.2026.111743

This study developed a biophysical model that integrates the characteristics of cancer stem cells (CSCs), including the side population (SP), and the oxygen enhancement effect (OER) to more accurately predict radiotherapy outcomes in prostate cancer. SP and main population (MP) cells were isolated from the DU145 prostate cancer cell line, and DNA double-strand breaks and survival were evaluated under both normoxic and hypoxic conditions (0.1% O). The obtained data were analyzed using the IMK model incorporating MP, SP, and oxygen concentration, and the predictions were compared with clinical tumor control probability (TCP) under various fractionation regimens (2, 3, and 7 Gy/Fx). As a result, the in vitro and clinical data were well reproduced by considering the MP/SP fraction, a population-independent OER, and the intratumoral hypoxic volume. Furthermore, the initial yield of DSBs was identified as a key determinant of radiosensitivity depending on cell characteristics and oxygen levels. The developed model is expected to contribute to the optimization of prostate cancer radiotherapy, including dose escalation to hypoxic tumor regions.

Trade-off between adsorption capacity and binding strength regulates carbon stabilization in mineral-associated organic matter

Sun, R.; Abe, Yukiko; Atarashi-Andoh, Mariko; Koarashi, Jun

Soil Biology & Biochemistry, 218, p.110150_1 - 110150_12, 2026/07

https://doi.org/10.1016/j.soilbio.2026.110150

The role of minerals in soil carbon sequestration has been increasingly recognized. However, the mechanism by which mineral-associated organic matter (MAOM) resists microbial decomposition remains an open question. We prepared MAOM on amorphous allophane and crystalline kaolinite with different organic matter (OM) proxies, characterized the affinity strength of these associations using isothermal titration calorimetry and X-ray photoelectron spectroscopy, and quantified their microbial mineralization through aerobic incubation. We found that amorphous allophane displayed greater OM adsorption capacity due to its higher specific surface area; in contrast, crystalline kaolinite exhibited stronger binding with OM, consistent with its predominant inner-sphere complexation. Furthermore, lower MAOM mineralization was found corresponding to higher Langmuir affinity. This inverse relationship was more pronounced than the correlation with the amount of OM adsorbed by minerals. These findings suggest that the overall MAOM stability is controlled by a balance between binding strength and adsorption capacity. Namely, stronger binding affinity enhances microbial resistance of MAOM, while the abundance of mineral sites determines the amount of MAOM accessible for microbial decomposition. This study presents a novel mechanistic understanding of the MAOM dynamics and refines the prevailing perspective on MAOM persistence.

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

Potential and solution conductivity inside stainless steel crevices in a very dilute bulk solution

Soma, Yasutaka; Komatsu, Atsushi; Igarashi, Takahiro

Corrosion Science, 265, p.113182_1 - 113182_13, 2026/06

https://doi.org/10.1016/j.corsci.2026.113812

Uncovering hidden dispersion patterns of radioactive cesium-rich microparticles from Fukushima Daiichi

Miyazaki, Kanako*; Fueda, Kazuki*; Kadowaki, Masanao; Terada, Hiroaki; Kozai, Naofumi; Iwata, Hajime; Horie, Kenji*; Takehara, Mami*; Yamasaki, Shinya*; Grambow, B.*; et al.

Journal of Hazardous Materials, 511, p.142180_1 - 142180_17, 2026/06

https://doi.org/10.1016/j.jhazmat.2026.142180

Implementation of a new function for handling nuclear data of outgoing particles and residual excitation states in PHITS

Furuta, Takuya; Hashimoto, Shintaro; Ogawa, Tatsuhiko; Tanimura, Yoshihiko

Nuclear Instruments and Methods in Physics Research A, 1086, p.171320_1 - 171320_8, 2026/06

https://doi.org/10.1016/j.nima.2026.171320

A new function to incorporate nuclear data libraries with outgoing particles plus residual nuclei in specific excitation states for neutron-induced reactions has been implemented in a Monte Carlo simulation code, Particle and Heavy Ion Transport code System (PHITS). With this function, accurate predictions of outgoing particle spectra and angular distributions according to the nuclear data libraries become possible, while accounting for production of residual nuclei and de-excitation gammas, conserving total energy and momentum in each event. This feature allows users to perform high-precision simulations of detector responses and radiation damage in materials.

Seismic reinforcement work of the Waste Treatment Facility No. 1 and the incinerator

Mori, Masakazu; Endo, Masayuki; Seya, Manato; Hozumi, Shinsei; Sudo, Tomoyuki

JAEA-Technology 2026-002, 33 Pages, 2026/05

JAEA-Technology-2026-002.pdf:2.01MB

The Waste Treatment Facility No. 1 is equipped with an incinerator for the treatment of radioactive combustible solid waste generated from facilities at the Nuclear Science Research Institute. To obtain conformity confirmation with the New Regulatory Requirements, seismic evaluations were conducted on the facility's building and its incineration equipment. As a result, neither the building nor the equipment satisfied the required seismic standards. Therefore, seismic reinforcement work for the building and equipment was carried out from April 2018 to March 2019. This report outlines the results of seismic evaluation and design, as well as the construction process and safety management during the seismic reinforcement work.