https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/196 Fri, 03 Jul 2026 22:24:08 GMT 2026-07-03T22:24:08Z https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/212490 Title: Effect of limestone and sulfate on the uptake of chloride and isosaccharinic acid by high-slag cement paste (CEM III/C) Authors: Jo, Yongheum; Szabo, Peter Gyula; Guidone, Rosa Ester; Lothenbach, Barbara; Cevirim-Papaioannou, Nese; Coppens, Erik; Altmaier, Marcus; Gaona, Xavier Abstract: The impact of SO42-and NaCl on the uptake of 36Cl-and isosaccharinic acid (ISA) by high-slag cement paste (CEM III/C) in the presence of CaCO3 was evaluated with systematic batch sorption experiments. The addition of CaCO3 resulted in a slight decrease in 36Cl-uptake, in line with previous studies. Enhanced sulfate concentration in the pore solution outcompeted 36Cl-sorption, resulting in very low distribution ratios (Rd). The increase in Rd at high NaCl concentrations is explained by the formation of Friedel's salt, confirmed by XRD and TG-DTA. ISA uptake remains unaffected in the presence of CaCO3, SO42-and NaCl, suggesting a differential sorption mechanism for 36Cl-and ISA. NaCl and ISA alter the pore solution composition, increasing [Ca] and [Si] as a result of the incongruent dissolution of cement hydrates. The impact of ISA is more pronounced due to the formation of complexes Ca-ISA. Wed, 01 Jul 2026 00:00:00 GMT https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/212490 2026-07-01T00:00:00Z https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/211849 Title: Fabrication and characterization of uniformly dispersed Pb(NO3)2-loaded 3D-printed plastic scintillators with enhanced gamma-ray detection capabilities Authors: Kang, Hyeong Gu; Yang, Han Cheol; Mindur, Bartosz; Szumlak, Tomasz; Kim, Yong Kyun Abstract: Plastic scintillators inherently suffer from the limitation of low gamma-ray counting efficiency due to their low atomic number (Z). To address this, this study explored the incorporation of lead (II) nitrate (Pb(NO3)2), a high-Z material, into a photocurable resin. The Pb(NO3)2-loaded plastic scintillators were fabricated using Digital Light Processing (DLP) type 3D printing, wherein dimethyl sulfoxide (DMSO) was employed as a co-solvent to ensure uniform dispersion of the Pb(NO3)2 within the polymer matrix. This uniform dispersion was confirmed by Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS) analysis of the scintillator's cutting surface. The evaluation of scintillation properties showed that the scintillator loaded with 5 wt% of Pb(NO3)2 exhibited a gamma-ray counting efficiency for a137Cs source that was 1.64 times higher than that of the commercial plastic scintillator, BC408. Although the optical transmittance decreased due to the addition of Pb(NO3)2 and DMSO, the 5 wt% Pb(NO3)2 sample maintained a relative light output of 55.51% compared to BC408. Additionally, the fast timing characteristics were preserved, with the loaded scintillators exhibiting a decay time of 3.23–3.41 ns, nearly identical to that of the unloaded sample. Wed, 01 Jul 2026 00:00:00 GMT https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/211849 2026-07-01T00:00:00Z https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/212728 Title: Node assigned physics-informed neural networks for thermal–hydraulic system simulation: CVH/FL/HS modules Authors: Shin, Jeesuk; Kim, Cheolwoong; Yang, Sunwoong; Lee, Minseo; Seo, Donggyun; Kim, Sung Joong; Jeon, Joongoo Abstract: Severe accidents (SAs) in nuclear power plants have been analyzed using thermal–hydraulic (TH) system codes such as MELCOR and MAAP. These codes efficiently simulate the progression of SAs, while they still have inherent limitations due to their inconsistent finite difference schemes. The use of empirical schemes incorporating both implicit and explicit formulations inherently induces unidirectional coupling in multi-physics analyses. The objective of this study is to develop a novel numerical method for TH system codes using physics-informed neural network (PINN). They have shown strength in solving multi-physics due to the innate feature of neural networks—automatic differentiation. We propose a node-assigned PINN (NA-PINN) that is suitable for the control volume approach-based system codes. NA-PINN addresses the issue of spatial governing equation variation by assigning an individual network to each nodalization of the system code, such that spatial information is excluded from both the input and output domains, and each subnetwork learns to approximate a purely temporal solution. In this phase, we evaluated the accuracy of the PINN methods for the hydrodynamic module. In the 6 water tank simulation, PINN and NA-PINN showed maximum absolute errors of 1.908146 and 0.003757, respectively. It should be noted that only NA-PINN demonstrated acceptable accuracy. The numerical feasibility of NA-PINN was also verified for a longer-term heat transfer case study. To the best of the authors’ knowledge, this is the first study to successfully implement a system code using PINN. Our future work involves extending NA-PINN to a multi-physics solver and developing it in a surrogate manner. © 2026 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies. Wed, 01 Jul 2026 00:00:00 GMT https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/212728 2026-07-01T00:00:00Z https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/212495 Title: Experimental validation of predominant radiative heat loss through a metal containment vessel of small modular reactors under normal operation Authors: Byeon, Geunyoung; Jeong, Beomjin; Kim, Namgook; Song, JinHo; Kim, Sung Joong Abstract: This study provides a systematic experimental quantification of the competing heat transfer mechanisms—conduction, natural convection, and radiation—within a representative, scaled geometry of a small modular reactor (SMR) equipped with a metal containment vessel (MCV). An experimental apparatus was developed to replicate the thermal behavior of the pressurizer region in a water-cooled SMR, enabling the evaluation of insulation performance under various environmental conditions: vacuum (∼0.07 bar), and nitrogen, argon, and carbon dioxide at atmospheric pressure. Results show that radiative heat transfer is the primary mode of heat loss, accounting for 44% to 83% of total heat transfer depending on the gap conditions. The vacuum condition demonstrated the lowest heat loss, owing to the suppression of convective heat transfer and the predominance of conduction and radiation. In contrast, carbon dioxide produced the highest heat loss due to its strong infrared absorption characteristics, which enhance radiative heat transfer. These findings underscore the critical role of radiation in thermal management within MCV-equipped SMRs. To enhance thermal efficiency and protect vital components from thermal degradation, insulation strategies should prioritize mitigating radiative heat transfer. This study offers foundational benchmark data on the partitioning of heat loss mechanisms, providing assessment for numerical models (e.g., CFD, system codes) used to optimize thermal insulation, improve reactor performance, and ensure structural integrity. By providing this crucial experimental data for model assessment, it contributes to the advancement of next-generation SMR containment design. Mon, 01 Jun 2026 00:00:00 GMT https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/212495 2026-06-01T00:00:00Z