Pub Date : 2026-03-01Epub Date: 2025-12-24DOI: 10.1016/j.nucengdes.2025.114687
Tri Nguyen , John Barton , Haomin Yuan , Casey Emler , Elia Merzari
This study presents high-fidelity Direct Numerical Simulations (DNS) of natural circulation flow of molten salt in a benchmark loop geometry using the GPU-accelerated spectral element code NekRS. The simulations focus on Test 5 from the University of Wisconsin-Madison FLiBe Natural Circulation Loop (UW-FNCL), using a computational model that matches the experimental setup in geometry, boundary conditions, and operational parameters. A low-Mach number formulation is employed to capture the strong temperature-dependent property variations inherent to FLiBe, a high-Prandtl-number molten salt. Validation against experimental data shows good agreement in temperature profiles and Nusselt numbers across a range of Reynolds numbers, demonstrating NekRS's capability to accurately and efficiently simulate buoyancy-driven flows with thermally varying fluid properties. Additionally, the DNS results provide novel insights into the three-dimensional flow and heat transfer characteristics that are challenging to obtain experimentally. Detailed flow analysis reveals pronounced buoyancy-induced velocity asymmetries in the bottom-heated leg, jet-driven shear instabilities in the reservoir, and localized unsteady phenomena near sharp bends. Proper Orthogonal Decomposition (POD) analysis identifies dominant energetic modes, highlighting a four-vortex Dean-like structure at the 90° elbow that deviates from classical two-vortex predictions, attributed to buoyancy-driven thermal stratification and pre-conditioned velocity profiles.
{"title":"High-fidelity simulation of molten salt natural circulation loops using the spectral element method","authors":"Tri Nguyen , John Barton , Haomin Yuan , Casey Emler , Elia Merzari","doi":"10.1016/j.nucengdes.2025.114687","DOIUrl":"10.1016/j.nucengdes.2025.114687","url":null,"abstract":"<div><div>This study presents high-fidelity Direct Numerical Simulations (DNS) of natural circulation flow of molten salt in a benchmark loop geometry using the GPU-accelerated spectral element code NekRS. The simulations focus on Test 5 from the University of Wisconsin-Madison FLiBe Natural Circulation Loop (UW-FNCL), using a computational model that matches the experimental setup in geometry, boundary conditions, and operational parameters. A low-Mach number formulation is employed to capture the strong temperature-dependent property variations inherent to FLiBe, a high-Prandtl-number molten salt. Validation against experimental data shows good agreement in temperature profiles and Nusselt numbers across a range of Reynolds numbers, demonstrating NekRS's capability to accurately and efficiently simulate buoyancy-driven flows with thermally varying fluid properties. Additionally, the DNS results provide novel insights into the three-dimensional flow and heat transfer characteristics that are challenging to obtain experimentally. Detailed flow analysis reveals pronounced buoyancy-induced velocity asymmetries in the bottom-heated leg, jet-driven shear instabilities in the reservoir, and localized unsteady phenomena near sharp bends. Proper Orthogonal Decomposition (POD) analysis identifies dominant energetic modes, highlighting a four-vortex Dean-like structure at the 90° elbow that deviates from classical two-vortex predictions, attributed to buoyancy-driven thermal stratification and pre-conditioned velocity profiles.</div></div>","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"448 ","pages":"Article 114687"},"PeriodicalIF":2.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
As a variant of the Method Of characteristics (MOC), The Random Ray Method (TRRM) stochastically generates the characteristic rays within the solution domain, making it a stochastic-deterministic hybrid method for the particle transport calculation. Compared to traditional MOC, TRRM significantly reduces computational memory footprint and greatly enhances the flexibility of MOC for a high-fidelity 3D simulation of reactors. However, the introduction of stochastic discretization leads to uncertainty with a convergence rate of in the results of TRRM, akin to the standard Monte Carlo method. This study focuses on improving the performance of TRRM by investigating different ray generation schemes, which are divided into two components: sampling methods and random number generation techniques. Three sampling strategies—uniform sampling, mesh-based stratified sampling, and Latin hypercube sampling—are combined with two random number generation techniques—pseudo-random numbers (PRN) and Low-Discrepancy Sequences (LDS)—to create six distinct schemes. The performance of these schemes is evaluated using the 2D C5G7 criticality benchmark and the 3D Kobayashi fixed-source benchmark. Numerical results from the C5G7 benchmark show that the combination of uniform sampling and LDS yields the best performance, reducing the uncertainty in keff and decreasing the required calculation time for active batches by more than a factor of seven. Latin hypercube sampling also demonstrates better performance, but its combination with LDS yields no benefits. For the Kobayashi benchmark, the uniform sampling with LDS also shows best performance, but advanced sampling methods like stratified and Latin hypercube sampling do not offer significant improvements and can introduce statistical oscillations. Therefore, the uniform sampling with LDS is highly recommended for TRRM on further applications.
{"title":"Impact of ray generation schemes on the random ray method for eigenvalue and shielding applications","authors":"Shuai Qin, Jiacheng Li, Xiangchun Tian, Shihong Li, Qian Zhang","doi":"10.1016/j.nucengdes.2025.114701","DOIUrl":"10.1016/j.nucengdes.2025.114701","url":null,"abstract":"<div><div>As a variant of the Method Of characteristics (MOC), The Random Ray Method (TRRM) stochastically generates the characteristic rays within the solution domain, making it a stochastic-deterministic hybrid method for the particle transport calculation. Compared to traditional MOC, TRRM significantly reduces computational memory footprint and greatly enhances the flexibility of MOC for a high-fidelity 3D simulation of reactors. However, the introduction of stochastic discretization leads to uncertainty with a convergence rate of <span><math><mi>O</mi><mfenced><msup><mi>N</mi><mrow><mo>−</mo><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup></mfenced></math></span> in the results of TRRM, akin to the standard Monte Carlo method. This study focuses on improving the performance of TRRM by investigating different ray generation schemes, which are divided into two components: sampling methods and random number generation techniques. Three sampling strategies—uniform sampling, mesh-based stratified sampling, and Latin hypercube sampling—are combined with two random number generation techniques—pseudo-random numbers (PRN) and Low-Discrepancy Sequences (LDS)—to create six distinct schemes. The performance of these schemes is evaluated using the 2D C5G7 criticality benchmark and the 3D Kobayashi fixed-source benchmark. Numerical results from the C5G7 benchmark show that the combination of uniform sampling and LDS yields the best performance, reducing the uncertainty in <em>k</em><sub>eff</sub> and decreasing the required calculation time for active batches by more than a factor of seven. Latin hypercube sampling also demonstrates better performance, but its combination with LDS yields no benefits. For the Kobayashi benchmark, the uniform sampling with LDS also shows best performance, but advanced sampling methods like stratified and Latin hypercube sampling do not offer significant improvements and can introduce statistical oscillations. Therefore, the uniform sampling with LDS is highly recommended for TRRM on further applications.</div></div>","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"448 ","pages":"Article 114701"},"PeriodicalIF":2.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-29DOI: 10.1016/j.nucengdes.2025.114697
Wenfu He , Yuxiang Zhou , Ziduan Shang , Tao Wang , Jiawei Ji
Isolation is widely recognized as one of the most effective technologies for protecting nuclear power structure (NPS) from seismic events. As with NPS, the seismic performance of nuclear plant isolated structure (NPIS) is affected not only by the inherent variability of seismic ground motions but also by significant uncertainties in structural characteristics. The addition of an isolation layer using isolation bearings introduces further uncertainty and raises concerns about the reliability of isolated structures. A probability density evolution method (PDEM) is proposed to evaluate the reliability of NPIS under various operational conditions. First, the NPIS is simplified into a nonlinear model representing the superstructure and the isolation layer, and a probability density evolution analysis procedure (PDEAP) is developed. The analysis considers the uncertainty of the parameters of the superstructure and the isolation layer and uses a Weibull distribution to model the skewed uncertainty. A shaking table test of the NPIS is then conducted. Finally, probability density analyses of the displacement are performed for the base earthquake (OBE), the safe shutdown earthquake (SSE) and the over-design base earthquake (2SSE and 3SSE). The shaking table test results indicate that, compared with the NPS, the NPIS reduces peak displacement by 38.71 %, 50.12 %, and 53.21 % under ground motion amplitudes of 0.3 g, 0.6 g, and 0.9 g, respectively. The probability density evolution analysis further reveals that as the peak ground acceleration (PGA) increases from the OBE to 3SSE, the displacement probability density function (PDF) transitions from a narrow, high peak to a broader, flatter distribution, indicating a significant increase in the variability of structural response.
{"title":"Probabilistic response analysis of skewed distribution of nuclear power plant structural parameters","authors":"Wenfu He , Yuxiang Zhou , Ziduan Shang , Tao Wang , Jiawei Ji","doi":"10.1016/j.nucengdes.2025.114697","DOIUrl":"10.1016/j.nucengdes.2025.114697","url":null,"abstract":"<div><div>Isolation is widely recognized as one of the most effective technologies for protecting nuclear power structure (NPS) from seismic events. As with NPS, the seismic performance of nuclear plant isolated structure (NPIS) is affected not only by the inherent variability of seismic ground motions but also by significant uncertainties in structural characteristics. The addition of an isolation layer using isolation bearings introduces further uncertainty and raises concerns about the reliability of isolated structures. A probability density evolution method (PDEM) is proposed to evaluate the reliability of NPIS under various operational conditions. First, the NPIS is simplified into a nonlinear model representing the superstructure and the isolation layer, and a probability density evolution analysis procedure (PDEAP) is developed. The analysis considers the uncertainty of the parameters of the superstructure and the isolation layer and uses a Weibull distribution to model the skewed uncertainty. A shaking table test of the NPIS is then conducted. Finally, probability density analyses of the displacement are performed for the base earthquake (OBE), the safe shutdown earthquake (SSE) and the over-design base earthquake (2SSE and 3SSE). The shaking table test results indicate that, compared with the NPS, the NPIS reduces peak displacement by 38.71 %, 50.12 %, and 53.21 % under ground motion amplitudes of 0.3 g, 0.6 g, and 0.9 g, respectively. The probability density evolution analysis further reveals that as the peak ground acceleration (PGA) increases from the OBE to 3SSE, the displacement probability density function (PDF) transitions from a narrow, high peak to a broader, flatter distribution, indicating a significant increase in the variability of structural response.</div></div>","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"448 ","pages":"Article 114697"},"PeriodicalIF":2.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A detailed experimental database was generated from hydrodynamic characterization a Wire Mesh Sensor (WMS) and a High-Speed Camera (HSC) in the TRISTAN facility and aerosol retention measurements in the SAAB facility, performed under identical injection conditions in the low-momentum globule regime. Nitrogen was injected through 5 mm and 10 mm nozzles, spanning a flow range of 1–10 ln/min, with a water submergence of 300 mm. This corresponds to a Weber number up to 7.3. HSC images showed aperiodic globule formation, revealing intensified bubble coalescence and break-up with increasing flow rates. The image processing demonstrated a high Gas Void Fraction (GVF) in the injection region, which increases with flow rate. The WMS data were collected at heights of 40, 100, and 200 mm above the nozzle tip. The data analysis mirrored GVF trends from the HSC images. Furthermore, the velocity profile of the gas phase was analyzed. Notably, the impact of the nozzle diameter is prominent in the injection region near the nozzle. An advanced algorithm was developed to track and extract globule formation characteristics from HSC images. A new scaling concept to describe globule characteristics as function of the Weber number was introduced and validated using additional experimental data. Based on this, a new correlation for the globule diameter is proposed for Weber number up to 70. Corresponding aerosol pool scrubbing tests were conducted and showed that particle retention is roughly insensitive to the gas flow rate within the experimental range, but is enhanced as particle inertia increases. In addition, use of the smaller nozzle under similar flow rates results mostly in a slight improvement of aerosol removal. These high-fidelity data can serve to develop and validate CFD models for hydrodynamics and aerosol pool scrubbing.
{"title":"Experimental investigations of Pool hydrodynamics and aerosol removal under low momentum injection","authors":"Nabil Ghendour , Detlef Suckow , Abdelouahab Dehbi , Michael Klauck","doi":"10.1016/j.nucengdes.2025.114735","DOIUrl":"10.1016/j.nucengdes.2025.114735","url":null,"abstract":"<div><div>A detailed experimental database was generated from hydrodynamic characterization a Wire Mesh Sensor (WMS) and a High-Speed Camera (HSC) in the TRISTAN facility and aerosol retention measurements in the SAAB facility, performed under identical injection conditions in the low-momentum globule regime. Nitrogen was injected through 5 mm and 10 mm nozzles, spanning a flow range of 1–10 l<sub>n</sub>/min, with a water submergence of 300 mm. This corresponds to a Weber number up to 7.3. HSC images showed aperiodic globule formation, revealing intensified bubble coalescence and break-up with increasing flow rates. The image processing demonstrated a high Gas Void Fraction (GVF) in the injection region, which increases with flow rate. The WMS data were collected at heights of 40, 100, and 200 mm above the nozzle tip. The data analysis mirrored GVF trends from the HSC images. Furthermore, the velocity profile of the gas phase was analyzed. Notably, the impact of the nozzle diameter is prominent in the injection region near the nozzle. An advanced algorithm was developed to track and extract globule formation characteristics from HSC images. A new scaling concept to describe globule characteristics as function of the Weber number was introduced and validated using additional experimental data. Based on this, a new correlation for the globule diameter is proposed for Weber number up to 70. Corresponding aerosol pool scrubbing tests were conducted and showed that particle retention is roughly insensitive to the gas flow rate within the experimental range, but is enhanced as particle inertia increases. In addition, use of the smaller nozzle under similar flow rates results mostly in a slight improvement of aerosol removal. These high-fidelity data can serve to develop and validate CFD models for hydrodynamics and aerosol pool scrubbing.</div></div>","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"448 ","pages":"Article 114735"},"PeriodicalIF":2.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-22DOI: 10.1016/j.nucengdes.2025.114708
Ahmad Salehi , Omid Safarzadeh , Ramazan Havangi
Ensuring robust control of small modular reactors (SMRs) is essential for safety and optimizing the performance of nuclear energy systems. Furthermore, accelerating integration of renewable energy sources like solar and wind into modern electricity grids has introduced certain challenges arising from inherent operational uncertainties and external disturbances. This variability has heightened the importance of using reliable power source such as SMRs with control systems capable of adjusting their power output dynamically in response to fluctuations in electricity demand. The SMART reactor is a small integral pressurized water reactor presented for enhancing the reliability and functionality of next-generation reactors. Achieving effective load-following in the SMART reactor necessitates advanced control systems that can ensure stability, safety, and performance under dynamic and uncertain conditions. The proposed robust control framework is compared with a conventional PID controller. The H∞ robust controller is also designed to study its performance in managing system uncertainty and external disturbances. This study aims to address these critical challenges by developing a robust control framework. The μ-synthesis method is employed to achieve stable and efficient controllers for the SMART reactor. The control systems are designed to handle complex dynamics of reactor, steam generator, and pressurizer to maintain power, pressure, and water level of the modular reactor. The findings indicate that the designed controllers are highly effective in managing the aforementioned feature, while maintaining stability across the entire operational conditions.
{"title":"Robust control of small integral pressurized water reactor using μ-synthesis","authors":"Ahmad Salehi , Omid Safarzadeh , Ramazan Havangi","doi":"10.1016/j.nucengdes.2025.114708","DOIUrl":"10.1016/j.nucengdes.2025.114708","url":null,"abstract":"<div><div>Ensuring robust control of small modular reactors (SMRs) is essential for safety and optimizing the performance of nuclear energy systems. Furthermore, accelerating integration of renewable energy sources like solar and wind into modern electricity grids has introduced certain challenges arising from inherent operational uncertainties and external disturbances. This variability has heightened the importance of using reliable power source such as SMRs with control systems capable of adjusting their power output dynamically in response to fluctuations in electricity demand. The SMART reactor is a small integral pressurized water reactor presented for enhancing the reliability and functionality of next-generation reactors. Achieving effective load-following in the SMART reactor necessitates advanced control systems that can ensure stability, safety, and performance under dynamic and uncertain conditions. The proposed robust control framework is compared with a conventional PID controller. The H<sub>∞</sub> robust controller is also designed to study its performance in managing system uncertainty and external disturbances. This study aims to address these critical challenges by developing a robust control framework. The <em>μ</em>-synthesis method is employed to achieve stable and efficient controllers for the SMART reactor. The control systems are designed to handle complex dynamics of reactor, steam generator, and pressurizer to maintain power, pressure, and water level of the modular reactor. The findings indicate that the designed controllers are highly effective in managing the aforementioned feature, while maintaining stability across the entire operational conditions.</div></div>","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"448 ","pages":"Article 114708"},"PeriodicalIF":2.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Corrigendum to “Effects of nanosilica and aggregate type on the mechanical, fracture and shielding features of heavyweight concrete” [Nucl. Eng. Des. 431 (2025) 113713]","authors":"Mohsen Ghorbani , Morteza Biklaryan , Morteza Hosseinali Beygi , Omid Lotfi-Omran","doi":"10.1016/j.nucengdes.2026.114751","DOIUrl":"10.1016/j.nucengdes.2026.114751","url":null,"abstract":"","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"448 ","pages":"Article 114751"},"PeriodicalIF":2.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study examines the durability of alkali-activated slag (AAS) concerning carbonation resistance, incorporating Nevastane (NEV) and Shellspirax (SHE) as surrogates for radioactive liquid organic waste. The findings reveal that vaterite is the predominant CaCO3 polymorph formed in the AAS-based specimens, regardless of the presence of oil. Furthermore, the mechanical strength of the AASs incorporating oil (waste forms) remains stable under carbonation conditions. The degree of carbonation of these waste forms is significantly influenced by the type of oil, waste loading, and water-to-binder (w/b) ratio. Notably, waste forms containing NEV exhibit superior carbonation resistance compared to those containing SHE. The encapsulation of oil within AAS matrices adversely affects the pore structure development, and exposure to accelerated carbonation further coarsens the microstructure. AAS matrices show potential for the immobilization of challenging radioactive liquid organic waste. Given the significant impact of oil type on carbonation extent, further testing with relevant radioactive liquid organic waste is necessary to ensure the durability of the waste form against carbonation before its application in real-world scenarios.
{"title":"Evolution in mechanical and microstructural properties of radioactive liquid organic waste-bearing alkali-activated slag under accelerated carbonation","authors":"Emile Mukiza , Thi Nhan Nguyen , Lander Frederickx , Quoc Tri Phung","doi":"10.1016/j.nucengdes.2025.114682","DOIUrl":"10.1016/j.nucengdes.2025.114682","url":null,"abstract":"<div><div>This study examines the durability of alkali-activated slag (AAS) concerning carbonation resistance, incorporating Nevastane (NEV) and Shellspirax (SHE) as surrogates for radioactive liquid organic waste. The findings reveal that vaterite is the predominant CaCO<sub>3</sub> polymorph formed in the AAS-based specimens, regardless of the presence of oil. Furthermore, the mechanical strength of the AASs incorporating oil (waste forms) remains stable under carbonation conditions. The degree of carbonation of these waste forms is significantly influenced by the type of oil, waste loading, and water-to-binder (w/b) ratio. Notably, waste forms containing NEV exhibit superior carbonation resistance compared to those containing SHE. The encapsulation of oil within AAS matrices adversely affects the pore structure development, and exposure to accelerated carbonation further coarsens the microstructure. AAS matrices show potential for the immobilization of challenging radioactive liquid organic waste. Given the significant impact of oil type on carbonation extent, further testing with relevant radioactive liquid organic waste is necessary to ensure the durability of the waste form against carbonation before its application in real-world scenarios.</div></div>","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"448 ","pages":"Article 114682"},"PeriodicalIF":2.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145753663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-01-02DOI: 10.1016/j.nucengdes.2025.114742
Suresh Seetharam , Quoc Tri Phung , Vojtech Galek , Anna Sears , Lander Frederickx , Eduardo Ferreira
This paper presents an experimental and numerical investigation of the thermal evolution of a conditioned molten salt oxidation (MSO) residue contained within 100 L drums. Three types of binders were employed: (i) alkali-activated material (AAM) with a metakaolin precursor (AAM_MK), (ii) AAM with a blast furnace slag (BFS) precursor, and (iii) a blended cement mix, each with varying waste loadings. The study primarily involved isothermal and semi-adiabatic calorimetry experiments to develop a comprehensive dataset of hydration curves, which serve as direct inputs for a heat transfer model. Drum-scale experiments on the reconditioned MSO residue waste with metakaolin precursor were successfully designed and executed. Thermal evolution within the drum was monitored using thermal sensors strategically placed at various locations. A standard heat transfer model was employed for blind predictions of thermal evolution within the drum. Calorimetric measurements of the different waste forms indicated that the addition of MSO residue delayed hydration and geopolymerization in both the cementitious and alkali-activated matrices. The numerical model reasonably captured the primary features of thermal evolution, particularly the peak measured temperature data (> 80 °C) at the core of the drum conditioned with the AAM_MK binder, while also highlighting the uncertainty in the sensitive model parameters. It is anticipated that for typical drum sizes exceeding 200 L used in pre-disposal storage, peak temperatures could surpass 100 °C. Consequently, further studies on the long-term stability of reconditioned waste forms exposed to high early age temperatures are warranted.
{"title":"Thermal evolution in molten salt conditioned waste drums","authors":"Suresh Seetharam , Quoc Tri Phung , Vojtech Galek , Anna Sears , Lander Frederickx , Eduardo Ferreira","doi":"10.1016/j.nucengdes.2025.114742","DOIUrl":"10.1016/j.nucengdes.2025.114742","url":null,"abstract":"<div><div>This paper presents an experimental and numerical investigation of the thermal evolution of a conditioned molten salt oxidation (MSO) residue contained within 100 L drums. Three types of binders were employed: (i) alkali-activated material (AAM) with a metakaolin precursor (AAM_MK), (ii) AAM with a blast furnace slag (BFS) precursor, and (iii) a blended cement mix, each with varying waste loadings. The study primarily involved isothermal and semi-adiabatic calorimetry experiments to develop a comprehensive dataset of hydration curves, which serve as direct inputs for a heat transfer model. Drum-scale experiments on the reconditioned MSO residue waste with metakaolin precursor were successfully designed and executed. Thermal evolution within the drum was monitored using thermal sensors strategically placed at various locations. A standard heat transfer model was employed for blind predictions of thermal evolution within the drum. Calorimetric measurements of the different waste forms indicated that the addition of MSO residue delayed hydration and geopolymerization in both the cementitious and alkali-activated matrices. The numerical model reasonably captured the primary features of thermal evolution, particularly the peak measured temperature data (> 80 °C) at the core of the drum conditioned with the AAM_MK binder, while also highlighting the uncertainty in the sensitive model parameters. It is anticipated that for typical drum sizes exceeding 200 L used in pre-disposal storage, peak temperatures could surpass 100 °C. Consequently, further studies on the long-term stability of reconditioned waste forms exposed to high early age temperatures are warranted.</div></div>","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"448 ","pages":"Article 114742"},"PeriodicalIF":2.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-01-02DOI: 10.1016/j.nucengdes.2025.114717
Eunsoo Lee, Sang Woon Kwon, Chang Hwa Lee
The sustainable management of spent nuclear fuel (SNF) poses significant challenges, particularly in reducing high-level radioactive waste. To address these issues, high-radiation-generating rare-earth elements (RE), must be converted into stable forms for safe long-term storage in a deep geological repository. This study explores the conversion of RECl3 (RE = Y, La, Ce, Pr, Nd, and Sm) to their corresponding oxides through reactive distillation via a solid–solid reaction with K2CO3. It is crucial for reducing the volume and increasing the safety of geological disposal of nuclear waste. Thermodynamic calculations indicate that the reaction between RECl3 and K2CO3 proceeds favorably without a molten salt, as evidenced by low Gibbs free energy values. Experimentally, the reaction was conducted by mixing RECl3 with K2CO3 in a 1: 2.55 M ratio, followed by heating at 550 °C under 0.9 bar and then at 850 °C under vacuum. X-ray diffraction and scanning electron microscopy analyses results confirm the effective conversion of RECl3 to high-purity RE oxides. Additionally, experiments using a simulated mixture of RECl3, reflecting actual SNF composition, yielded the same results, demonstrating that RE oxides can be produced even in mixtures. It further emphasizes the process's applicability to real-world SNF management. The proposed approach can enhance the process efficiency as this method allows the oxidation of RECl3 and the subsequent separation of byproduct (KCl and CO2) to be performed within one reactor.
{"title":"Reactive distillation of rare earth elements via solid–solid reaction for treatment of spent nuclear fuel","authors":"Eunsoo Lee, Sang Woon Kwon, Chang Hwa Lee","doi":"10.1016/j.nucengdes.2025.114717","DOIUrl":"10.1016/j.nucengdes.2025.114717","url":null,"abstract":"<div><div>The sustainable management of spent nuclear fuel (SNF) poses significant challenges, particularly in reducing high-level radioactive waste. To address these issues, high-radiation-generating rare-earth elements (RE), must be converted into stable forms for safe long-term storage in a deep geological repository. This study explores the conversion of RECl<sub>3</sub> (RE = Y, La, Ce, Pr, Nd, and Sm) to their corresponding oxides through reactive distillation via a solid–solid reaction with K<sub>2</sub>CO<sub>3</sub>. It is crucial for reducing the volume and increasing the safety of geological disposal of nuclear waste. Thermodynamic calculations indicate that the reaction between RECl<sub>3</sub> and K<sub>2</sub>CO<sub>3</sub> proceeds favorably without a molten salt, as evidenced by low Gibbs free energy values. Experimentally, the reaction was conducted by mixing RECl<sub>3</sub> with K<sub>2</sub>CO<sub>3</sub> in a 1: 2.55 M ratio, followed by heating at 550 °C under 0.9 bar and then at 850 °C under vacuum. X-ray diffraction and scanning electron microscopy analyses results confirm the effective conversion of RECl<sub>3</sub> to high-purity RE oxides. Additionally, experiments using a simulated mixture of RECl<sub>3</sub>, reflecting actual SNF composition, yielded the same results, demonstrating that RE oxides can be produced even in mixtures. It further emphasizes the process's applicability to real-world SNF management. The proposed approach can enhance the process efficiency as this method allows the oxidation of RECl<sub>3</sub> and the subsequent separation of byproduct (KCl and CO<sub>2</sub>) to be performed within one reactor.</div></div>","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"448 ","pages":"Article 114717"},"PeriodicalIF":2.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145885267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-16DOI: 10.1016/j.nucengdes.2025.114680
Toni Karlsson , Abdalla Abou-Jaoude , Ramiro Oscar Freile , Morgan Kropp , Steve Warmann , Evan Lovel , Brian Kajganich , Marc Babcock , Katie Hawkins , Calvin Downey , Mauricio Tano Retamales , William Phillips , Glen Papaioannou , Chuting Tsai , Michael Ruddell , Reed Eichele , Steven Pappas , Charles Pierce Jones III , Richard M. Cox , Patricia Paviet
Molten salt reactors (MSRs) are gaining attention due to their potential for safe, carbon-free nuclear energy with reduced waste. However, licensing these reactors is hindered by limited experimental data on fueled salts, both pre- and post-irradiation. The novel Molten-salt Research Temperature-controlled Irradiation (MRTI) vehicle was designed to address knowledge gaps in irradiating enriched‑uranium-bearing salts. The MRTI experiment irradiated 13 cm3 of UCl₃-NaCl (93 % U-235) salt in the Neutron Radiography (NRAD) Reactor, achieving a burnup of 0.196 GWd/MTU over 390 h. Despite a heater failure, the thermocouple data suggested fission heat kept the salt molten. The MRTI assembly was remotely disassembled for nondestructive post-irradiation examination (PIE), which included precision gamma-ray scanning (PGS) and neutron radiography. Radiograph images showed the location of the salt and the solidification pattern. PGS results provided an early indication that activated materials of construction did not increase in relative intensity in the region of the capsule where the salt was in contact with the material of construction. Additionally, PGS data showed the presence of several gamma emitting fission products, such as Nb-95, Zr-95, Ru-103, Ce-141, and La-140, where Ru-103 had the highest counts at the bottom of the capsule. Computational fluid dynamics modeling supported observations of salt solidification patterns and proved to be a valuable tool to inform PIE activities. The MRTI experiment has thus far provided critical data and lessons learned for fuel salt PIE activities, essential for advancing the technical readiness of MSRs.
{"title":"Irradiation of an enriched uranium (NaCl-UCl3) fuel salt capsule, summary of nondestructive post-irradiation examinations, and solidification modeling","authors":"Toni Karlsson , Abdalla Abou-Jaoude , Ramiro Oscar Freile , Morgan Kropp , Steve Warmann , Evan Lovel , Brian Kajganich , Marc Babcock , Katie Hawkins , Calvin Downey , Mauricio Tano Retamales , William Phillips , Glen Papaioannou , Chuting Tsai , Michael Ruddell , Reed Eichele , Steven Pappas , Charles Pierce Jones III , Richard M. Cox , Patricia Paviet","doi":"10.1016/j.nucengdes.2025.114680","DOIUrl":"10.1016/j.nucengdes.2025.114680","url":null,"abstract":"<div><div>Molten salt reactors (MSRs) are gaining attention due to their potential for safe, carbon-free nuclear energy with reduced waste. However, licensing these reactors is hindered by limited experimental data on fueled salts, both pre- and post-irradiation. The novel Molten-salt Research Temperature-controlled Irradiation (MRTI) vehicle was designed to address knowledge gaps in irradiating enriched‑uranium-bearing salts. The MRTI experiment irradiated 13 cm<sup>3</sup> of UCl₃-NaCl (93 % U-235) salt in the Neutron Radiography (NRAD) Reactor, achieving a burnup of 0.196 GWd/MTU over 390 h. Despite a heater failure, the thermocouple data suggested fission heat kept the salt molten. The MRTI assembly was remotely disassembled for nondestructive post-irradiation examination (PIE), which included precision gamma-ray scanning (PGS) and neutron radiography. Radiograph images showed the location of the salt and the solidification pattern. PGS results provided an early indication that activated materials of construction did not increase in relative intensity in the region of the capsule where the salt was in contact with the material of construction. Additionally, PGS data showed the presence of several gamma emitting fission products, such as Nb-95, Zr-95, Ru-103, Ce-141, and La-140, where Ru-103 had the highest counts at the bottom of the capsule. Computational fluid dynamics modeling supported observations of salt solidification patterns and proved to be a valuable tool to inform PIE activities. The MRTI experiment has thus far provided critical data and lessons learned for fuel salt PIE activities, essential for advancing the technical readiness of MSRs.</div></div>","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"448 ","pages":"Article 114680"},"PeriodicalIF":2.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号