The non-contact membrane distillation(MD) method developed by researchers at the University of South China marks a notable advancement over traditional direct contact membrane distillation approaches. Conventional MD methods encounter substantial limitations, such as shortened membrane lifespan due to continual contact with contaminants, low and inconsistent membrane flux, and inadequate mechanisms for real-time membrane damage monitoring. These challenges significantly reduce the operational efficiency and reliability of MD in practical applications, particularly in environments where stable, uninterrupted performance is critical. The non-contact MD method, however, minimizes the direct interaction between the membrane and feed solution, thereby markedly extending the membrane’s functional lifespan and enhancing its flux stability, rendering it more suitable for long-term, large-scale deployment. This study aims to adapt the non-contact MD technique for on-site volume reduction and purification of radioactive wastewater generated by nuclear power plants, hospitals, and similar facilities. To meet the specific requirements of these applications, the researchers referenced established design frameworks for non-contact MD devices and incorporated heat pump waste heat recovery technology. This integration not only improves energy efficiency but also addresses the need for an economical and practical treatment system. By utilizing heat pump technology, energy consumption in the MD process is reduced by approximately 26%, with projected energy use maintained below 500 kW•h per ton of wastewater treated. Such energy efficiency is essential for large-scale application, enhancing both the economic feasibility and sustainability of radioactive wastewater treatment. A pilot-scale engineering prototype was designed, constructed, and rigorously evaluated to determine its performance metrics. Experimental results indicate that the prototype achieves a robust membrane flux of over 20 kg/(m2•h). Additionally, the prototype’s wastewater treatment capacity is flexible, ranging from 16.58 kg/h to 75.15 kg/h based on operational settings. This adjustable treatment capacity allows operators to calibrate the processing rate in real time, aligning the system’s functionality with varying demands and expanding its applicability across diverse use cases. The prototype demonstrated superior ion removal efficiency for wastewater treatment. Conductivity assessments revealed an ion removal efficiency of 99.7%, while retention rates for simulated radioactive contaminants such as strontium(Sr2+) and iodine(I−) surpassed 99.9%. These findings underscore the prototype’s capability to treat radioactive wastewater effectively, ensuring that the treated effluent meets stringent environmental safety standards. In summary, the successful design and validation of this engineering prototype establish a robust technical foundation for the future development of compact, on-site radioactive wastewater treatment systems. Such systems have the potential to substantially mitigate the environmental impact of radioactive wastewater from nuclear and healthcare facilities, advancing safer, more sustainable waste management solutions.
Nuclear engineering. Atomic power, Chemical technology
Various approaches have been proposed to address the challenges associated with storage and disposal of spent nuclear fuel. Rod consolidation, which involves extracting only the fuel rods from fuel assemblies and combining them for storage with reduced spacing, gained attention until the 1990s for its benefits in storage efficiency. In this case study, experts from diverse backgrounds evaluate the technical and political feasibility of rod consolidation for enhancing disposal practices. This study conducts a technical and regulatory analysis of rod consolidation under disposal conditions and evaluates its feasibility from a disposal perspective. From a technical viewpoint of 2:1 and 1.5:1 rod consolidations, the rod consolidation methods demonstrate positive effects on nuclear criticality compared to the reference, non-rod consolidation case. For the advanced repository design with elevated temperature conditions of 150 °C or higher, the applicability of rod consolidation becomes more convincing, thereby achieving a reduction in the number of required disposal canisters. In addition, regulatory considerations primarily focus on the requirements for applying rod consolidation technology under the Korea Nuclear Act. Moreover, this research conducts environmental, economic, and acceptance analyses to ascertain the viability of rod consolidation. The findings provide compelling evidence supporting the feasibility of rod consolidation technology for disposal purposes, highlighting its technical, regulatory, economic, environmental, and societal acceptance advantages. However, challenges remain, particularly concerning its applicability to high-burnup nuclear fuel and unresolved regulatory and technical issues.
A new, user-friendly software called Interaction of Charged Particle has been developed to simulate ion interactions across various applications. Designed with robust physical formulations and computational techniques using Python packages, InChaP operates within a broad energy range of 0.01–1000 MeV. InChaP calculates mass stopping power, stopping cross-section, relative stopping power, effective atomic number, and electron density for any chemical compound or composite using a logarithmic interpolation procedure across a wide range of ion energies. It also generates parameters for a specific ion of energy within the working range, and users can obtain the results in common spreadsheet formats. The software is freely available to all researchers. Good agreements were obtained in the effective atomic number between InChaP and some possible results from literature. These agreements were diff.%≤11.44 and diff.%≤1.94 for He ion interaction and for electron interaction in calculation of effective atomic number for spleen at 1 MeV.
Copper oxidation at low temperatures below 140 °C and its effects on corrosive behavior in aerobic groundwater are investigated to estimate the intactness of canisters at early stages of disposal. The Cu coupon surface is covered by fine particles that form thin oxide layers after 30 d of oxidation; a thin Cu2O layer of thickness <100 nm is formed after oxidation at 40 °C; after oxidation at 140 °C, the Cu2O surface changes to a CuO layer of thickness <500 nm. The thickness of the Cu surface oxidized at 90 °C is between those of the surfaces oxidized at 40 and 140 °C. All Cu coupons exhibit similar current densities ranging from 0.77 to 1.87 μA cm−2, although the corrosion potential of the Cu coupon layered with Cu2O is higher than that of the others. Long-term oxidation tests for 406 d reveal no significant changes in the Cu surface at temperatures below 90 °C, indicating no significant change in the electrochemical behavior. The results of this study suggest that the storage of canisters at temperatures below 90 °C has no significant effect on the degradation of canister performance in long-term disposal.
ZHOU Ziyang1, ZHANG Haochun1, , YOU Ersheng2, MIAO Xinyu1, LI Keyi1
With mankind’s growing desire to explore the universe, deep space exploration missions have become a hot topic in scientific research and technology. These missions are often required to operate for long periods of time in extreme environments, placing high demands on energy systems. Especially in deep space far away from the sun, solar energy resources become scarce and more reliable and efficient energy solutions need to be found. Facing the need for high-power space nuclear power systems for deep space exploration missions, a dual-mode nuclear thermal propulsion system based on the regenerative Brayton cycle was designed. To meet the design needs of the dual-mode nuclear thermal propulsion system, mathematical modeling of the system was carried out from the propulsion and power generation parts, and the composition of each component and the main influence parameters of the two modules were analyzed. With regard to the selection of the Brayton cycle system, the specific heat capacity ratio, density, viscosity and thermal conductivity of He-Xe, He-sCO2 and He-N2O, which are the common work materials in the space Brayton cycle, were compared to investigate their thermodynamic properties and transportation characteristics. The aforementioned properties of He-Ar mixed media were proposed and investigated, as well as the effects of helium mass fraction on the two main properties of He-Ar mixed media, namely specific heat capacity ratio and viscosity. In order to address the problem of conflicting optimal choices for each system performance parameter, the expressions derived above were used to optimize the system by using the non-dominated sorted whale optimization algorithm as the objective function for specific impulse, thermal efficiency and cyclic work. Finally, the main parameters affecting the dual-mode nuclear thermal propulsion system, the optimal choice of the nuclear thermal propulsion part, the changes in the properties and advantages and disadvantages of each work material at different temperatures and pressures, the advantages of the He-Ar hybrid work material in terms of its thermodynamic properties and the shortcomings of its transport properties were found, and the optimal solution of the Pareto front for the system’s multi-objective optimization was obtained.
Purpose: This retrospective comparative study aims to evaluate the clinical efficacy of two-dimensional (2D) navigation-guided percutaneous endoscopic transforaminal discectomy in comparison to conventional microscopic surgery for the treatment of lumbar disc herniation (LDH), based on operative time, blood loss, and X-ray examination parameters. Methods: Clinical data of patients who underwent either 2D navigation-assisted endoscopic (2D-NAE) discectomy or conventional microscopic surgery for LDH were retrospectively reviewed. Baseline characteristics, perioperative data, clinical outcomes (including visual analog scale [VAS] scores, Oswestry Disability Index [ODI] scores, and Modified MacNab criteria), and complications were compared between the two groups. Results: A total of 95 patients were included, with 80 having complete follow-up data. The 2D navigation group comprised 47 patients, while the conventional microscopic surgery group had 33 patients. Both groups showed significant improvement in VAS and ODI scores at each follow-up time point (P < 0.05). The perioperative analysis favored the 2D navigation-assisted group, with a significantly shorter operative time (42.77 ± 7.56 vs. 59.33 ± 3.30 min; p < 0.01) and lower blood loss (10.34 ± 2.24 vs. 11.55 ± 2.20 ml; p = 0.02). The number of X-ray examinations required was similar between the two groups (2.34 ± 0.48 vs. 2.39 ± 0.56; p = 0.65), and post-operative hospitalization durations were comparable (p = 0.5). Clinical efficacy, as reflected by VAS scores for legs and ODI scores, showed no significant differences between the groups. Additionally, the Modified MacNab criteria indicated similar rates of excellent and good outcomes. Conclusion: Both 2D-NAE discectomy and conventional microscopic surgery demonstrated comparable therapeutic outcomes for LDH, with favorable clinical efficacy and safety profiles. However, 2D-NAE surgery may offer additional benefits, including shorter operative times, reduced blood loss, and fewer X-ray examinations.
Medical physics. Medical radiology. Nuclear medicine, Nuclear engineering. Atomic power
An analytical model of helium-induced fuzz growth on heated tungsten (Patino et al., 2023) is expanded to include the effects of material exposure temperature via an Arrhenius relation and helium-induced sputtering. The expanded model is able to replicate experimental measurements of fuzz thickness for a range of helium fluences from 0.7–110×1026 m−2, sample temperatures from 993–1300 K, and ion energies from 50–500 eV.
WANG Hui;XING Ji;SUN Zhongning;GU Haifeng;SUN Xiaohui;WANG Yibo
The transport and retention of aerosols in the containment gap are closely related to the gas flow in the cracks. In order to evaluate the aerosol retention efficiency in the cracks after an accident by the existing aerosol penetration coefficient relationships, taking the capillary as the representative crack, a methodology for pressure difference driven gas flow calculation was proposed based on the one-dimensional compressible adiabatic flow equation, and the calculation program was compiled based on FORTRAN language. The input parameters of the program were capillary upstream pressure and temperature, downstream pressure, capillary length, inner diameter and roughness. When calculating the resistance, the classical laminar resistance relationship and turbulent Colebrook relationship were adopted, and the form resistance coefficients at the inlet and outlet of the capillary were 0.5 and 1.0 respectively. The program can calculate the subsonic speed, critical speed and choking state of air flow. The one-dimensional calculation method was validated by the capillary flow characteristic experiment carried out by Kagoshima University in Japan. The capillary length is 12 cm, the inner diameter is 397 μm and the roughness was 0.02%. The downstream pressure of the test was 100 kPa and the upstream pressure was 150-700 kPa. In addition, in order to obtain the detailed flow information in the capillary, the computational fluid dynamics (CFD) software ANSYS Fluent 19.2 was also used to model and calculate the experimental device. The structured grid scheme was adopted in the CFD modeling, and the number of grids was about 1.7 million. The numerical results show that the flow change trend is consistent, and most of the deviation between the gas flow and the experimental value is less than 10%, which proves the accuracy and rationality of the one-dimensional calculation method, and the efficiency of one-dimensional calculation method is better than that of CFD method. On this basis, the influences of pressure difference and inner diameter on gas flow were analyzed by one-dimensional calculation method. The results show that the leakage flow of small inner diameter capillary increases quadratic with the increase of pressure difference, and when the inner diameter is greater than 100 μm, the growth trend of mass flow transits to linearization if the pressure difference exceeds a certain value. When the pressure difference makes the flow in the transition zone between laminar flow and turbulence, the leakage flow through the capillary tube will appear a platform, affected by the change trend of resistance coefficient. The larger the inner diameter, the earlier the platform appears. The results of this paper can provide a technical basis for the retention evaluation of aerosols in the cracks. In the follow-up, the numerical methodology will be extended to the analysis of pressure-driven gas flow with multi-components through capillary tubes.
Andrew Walker, Joshua Racette, Takumi Saito
et al.
Selenium has been identified as an element of interest for the safety assessment of a deep geological repository (DGR) for used nuclear fuel. In Canada, groundwaters at DGR depths in sedimentary rocks have been observed to have a high ionic strength. This paper examines the sorption behavior of Se(-II) onto illite, MX-80 bentonite, Queenston shale, and argillaceous limestone in Na–Ca–Cl solutions of varying ionic strength (0.1–6 mol/kgw (m)) and across a pH range of 4–9. Little ionic strength dependence for Se(-II) sorption onto all solids was observed except that sorption at high ionic strength (6 m) was generally slightly lower than sorption at low ionic strength (0.1 m). Illite and MX-80 exhibited the expected results for anion sorption, while shale and limestone exhibited more constant sorption across the pH range tested. A non-electrostatic surface complexation model successfully predicted sorption of Se(-II) onto illite and MX-80 using the formation of an inner-sphere surface complex and an outer-sphere surface complex. Optimized values for the formation reactions of these surface species were proposed.
The analysis of rapid flow transients in Reactor Coolant Pumps (RCP) is essential for a reactor safety study. An accurate and precise analysis of the RCP coastdown is necessary for the reactor design. The coastdown of RCP affects the coolant temperature and the colloidal crud in the primary coolant. A realistic and kinetic model has been used to investigate the behavior of activated colloidal crud in the primary coolant and steam generator that solves the pump speed analytically. The analytic solution of the non-dimensional flow rate has been determined by the energy ratio β. The kinetic energy of the coolant fluid and the kinetic energy stored in the rotating parts of a pump are two essential parameters in the form of β. Under normal operation, the pump's speed and moment of inertia are constant. However, in a coastdown situation, kinetic damping in the interval has been implemented. A dynamic model ACCP-SMART has been developed for System Integrated Modular and Advanced Reactor (SMART) to investigate the corrosion due to activated colloidal crud. The Fickian diffusion model has been implemented as the reference corrosion model for the constituent component of the primary loop of the SMART reactor. The activated colloidal crud activity in the primary coolant and steam generator of the SMART reactor has been studied for different equilibrium corrosion rates, linear increase in corrosion rate, and dynamic RCP coastdown situation energy ratio β. The coolant specific activity of SMART reactor equilibrium corrosion (4.0 mg s−1) has been found 9.63 × 10−3 μCi cm−3, 3.53 × 10−3 μC cm−3, 2.39 × 10−2 μC cm−3, 8.10 × 10−3 μC cm−3, 6.77 × 10−3 μC cm−3, 4.95 × 10−4 μC cm−3, 1.19 × 10−3 μC cm−3, and 7.87 × 10−4 μC cm−3 for 24Na, 54Mn, 56Mn, 59Fe, 58Co, 60Co, 99Mo, and 51Cr which are 14.95%, 5.48%, 37.08%, 12.57%, 10.51%, 0.77%, 18.50%, and 0.12% respectively. For linear and exponential coastdown with a constant corrosion rate, the total coolant and steam generator activity approaches a higher saturation value than the normal values. The coolant and steam generator activity changes considerably with kinetic corrosion rate, equilibrium corrosion, growth of corrosion rate (ΔC/Δt), and RCP coastdown situations. The effect of the RCP coastdown on the specific activity of the steam generators is smeared by linearly rising corrosion rates, equilibrium corrosion, and rapid coasting down of the RCP. However, the time taken to reach the saturation activity is also influenced by the slope of corrosion rate, coastdown situation, equilibrium corrosion rate, and energy ratio β.
Industrial waste-based geopolymer cement is a greener alternative to Ordinary Portland Cement (OPC) for radiation shielding with comparable mechanical properties without the production of CO2 during synthesis. In this paper, the linear attenuation coefficient of slag and fly ash-based geopolymers, unmodified by aggregates, is measured and used to calculate the mass attenuation coefficients, half-value layer (HVL), and tenth-value layer (TVL) of the geopolymers. Narrow Beam Gamma Spectrometry with gamma energy of 0.662 MeV, 1.173 MeV, and 1.332 MeV was used to irradiate a series of slag and fly ash-based geopolymer paste of cylindrical shape with a diameter of 7.5 cm and height of 9.5 cm. Slag geopolymer has linear attenuation coefficient of 0.1642/cm, 0.1237/cm, 0.1150/cm, mass attenuation coefficient of 0.0782 cm2/g, 0.0589 cm2/g, 0.0548 cm2/g, the HVL of 4.222 cm, 5.609 cm, 6.056 cm, and TVL of 14.025 cm, 18.633 cm, 20.118 cm, respectively. Fly ash geopolymer has linear attenuation coefficient of 0.1387/cm, 0.1075/cm, and 0.0964/cm, mass attenuation coefficient of 0.0761 cm2/g, 0.0589 cm2/g, 0.0529 cm2/g, HVL of 4.998 cm, 6.453 cm, 7.202 cm, and TVL of 16.603 cm, 21.437 cm, 23.926 cm, respectively. Test samples made from slag-based geopolymers have a better shielding capability compared to fly ash-based geopolymers due to having higher attenuation coefficients as well as lower HVL and TVL, thus requiring less material to absorb radiation of the same energy level.
Cross sections and fission yields can be correlated, depending on the selection of integral experimental data. To support this statement, this work presents the use of experimental isotopic compositions (both for actinides and fission products) from a sample irradiated in a reactor, to construct correlations between various cross sections and fission yields. This study is therefore complementing previous analysis demonstrating that different types of nuclear data can be correlated, based on experimental integral data.
Aluminum nitride (AlN) and aluminum oxide (Al2O3) were exposed to deuterium (D) and helium (He) plasma in the PISCES-A linear plasma device using RF biasing of the sample manipulator to set the incident ion energy (16–100 eV, 0.7–12 × 1025 m−2, <600 K). Preferential sputtering of nitrogen was detected for D and He exposed AlN samples, resulting in Al enrichment at the surface (i.e., Al/N ~2–3). The Al-enriched region was limited to the uppermost ~20 nm, independent of fluence, and was eliminated by exposure to plasma seeded with nitrogen. No Al enrichment was observed for the Al2O3 samples exposed to pure D or He. Results suggest AlN and Al2O3 are promising candidates as plasma facing materials in magnetic fusion and RF plasma devices (e.g., as electrical standoffs and RF heating windows).
Institute for Plasma Research, Gandhinagar 382 428, India Department of Physics, The M S University of Baroda 390 002, India ITER-India, Gandhinagar 382 428, India Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India Department of Electrical Power Engineering, Brno University of Technology, Brno 61600, Czech Republic
Several mathematical models that explain natural phenomena are mostly formulated in terms of nonlinear differential equations. Many problems in applied sciences such as nuclear physics, engineering, thermal management, gas dynamics, chemical reaction, studies of atomic structures and atomic calculations lead to singular boundary value problems and often only positive solutions are vital. However, most of the methods developed in mathematics are used in solving linear differential equations. For this reason, this research considered a model problem representing temperature distribution in heat dissipating fins with triangular profiles using MATLAB codes. MADM was used with a computer code in MATLAB to seek solution for the problem involving constant and a power law dependence of thermal conductivity on temperature governed by linear and nonlinear BVPs, respectively, for which considerable results were obtained. A problem formulated dealing with a triangular silicon fin and more examples were solved and analyzed using tables and figures for better elaborations where appreciable agreement between the approximate and exact solutions was observed. All the computations were performed using MATHEMATICA and MATLAB.