Search Results (65)

Lead–bismuth eutectic (LBE), while advantageous for advanced nuclear reactors due to its thermophysical properties, faces oxidation and corrosion challenges during operation. This study aims to optimize gas-phase oxygen control by computationally analyzing oxygen transport dynamics in an LBE loop. High-fidelity simulations were performed using ANSYS Fluent and STAR-CCM+ based on the CORRIDA loop geometry, employing detailed meshing for convergence. Steady-state analyses revealed localized oxygen enrichment near the gas–liquid interface (peaking at ∼$3\times {10}^{-6}$ wt%), decreasing to ∼$5.0-6.8\times {10}^{-8}$ wt% at the outlet. Transient simulations from an oxygen-deficient state ($1\times {10}^{-8}$ wt%) demonstrated distribution stabilization within 150 s, driven by convection-enhanced diffusion. Parametric studies identified a non-monotonic relationship between inlet velocity and oxygen uptake, with optimal performance at 0.7–0.9 m/s, while increasing temperature from 573 K to 823 K monotonically enhanced the outlet concentration by >$200\%$ due to improved diffusivity/solubility. The average mass transfer coefficient (0.6–0.7) aligned with literature values ($\pm 20\%$ deviation), validating the model’s treatment of interface thermodynamics and turbulence. These findings the advance mechanistic understanding of oxygen transport in LBE and directly inform the design of oxygenation systems and corrosion mitigation strategies for liquid metal-cooled reactors. Full article

The Dual Fluid Reactor (DFR) is a Generation IV concept that relies on a phased development pathway using a low-temperature microdemonstrator ($\mu$DEMO) and a high-temperature minidemonstrator (mDEMO). A rigorous methodology is required to scale experimental data between these facilities to ensure the reliable design of the final reactor. This paper establishes such a methodology grounded in Similarity Theory. The Cathare-2 system code was used to perform a parametric study on a simplified model of the demonstrators, which use lead–bismuth eutectic and pure liquid lead, respectively. This study focused on identifying the specific operating conditions required to match key “defining” dimensionless numbers—the Reynolds number (Re) for dynamic similarity and the Peclet number (Pe_h) for thermal similarity. The analysis successfully identified and presented the distinct operating ranges of fluid velocity and mass flow required to achieve either state. Results show that matching the Reynolds number allows for the dimensionless pressure drop to be scaled with a deviation below 0.2%, while matching the Peclet number allows for the dimensionless temperature profile to be scaled with a deviation under 2.5%. The central finding is that dynamic and thermal similarity cannot be achieved simultaneously due to the different working fluids and temperatures of the demonstrators. This forces a strategic choice in experimental design, where an experiment must be tailored to investigate either fluid dynamics or heat transfer. This work provides the foundational “rulebook” for designing these crucial experiments, ensuring that data from the DFR demonstrator program is both reliable and scalable. Full article

A key issue with lead-cooled fast reactors is the corrosion vulnerability of fuel cladding and core components, which will endanger the structural materials’ integrity and the operational safety of the reactor system. The FeCrAlTi-ODS (Oxide Dispersion Strengthened) alloy coatings are prepared by the Magnetron Sputtering technique under different bias voltages to shield structural elements in lead-cooled fast reactors from corrosion caused by lead-bismuth eutectic (LBE). A comprehensive study examines their mechanical attributes and resistance to LBE-induced corrosion. Compared to the bare substrate of austenitic 316L steel, the FeCrAlTi-ODS alloy coatings exhibit significantly improved binding force and hardness. The hardness (H) reaches 11.52 GPa (twice that of the bare substrate), and the elastic modulus (E) reaches 172.89 GPa. After the corrosion of bare substrate 316L steel by LBE, the oxygen element penetrated was obvious, and the Nickel element underwent selective migration. The FeCrAlTi-ODS alloy coatings show promising LBE corrosion resistance, and the FeCrAlTi-ODS alloy coating prepared under different bias can effectively protect the substrate material, which is attributed to the formation of protective FeCr₂O₄ film on the surface. The compact oxide film significantly prevents the further infiltration of the oxygen element and the migration of metal elements. Full article

Lead–bismuth eutectic alloy (LBE, Pb_44.5Bi_55.5) has emerged as a promising candidate for use in advanced nuclear and solar energy systems due to its favorable thermophysical characteristics and radiation shielding capabilities. The aim of this research is to assess the applicability of the induction melting technique to synthesize LBE. This paper presents a comprehensive evaluation of the structural, thermophysical, and radiation shielding properties of the obtained LBE sample. Various techniques were employed to investigate the solid-to-liquid eutectic transformation, phase composition, morphology, and homogeneity of the obtained material. Experimental and theoretical determinations on density, void, molar volume, thermal conductivity, heat capacity, thermal diffusivity, and electrical conductivity were performed. Radiation shielding performance over photon energies ranging from 0.015 to 15 MeV was simulated using the Phy-X/PSD program. The results revealed the eutectic structure comprising Pb₇Bi₃ and Bi phases with near-ideal stoichiometry and a melting point of 127.6 °C. The alloy demonstrated a small void that corresponds to a high degree of sample compaction, high specific heat capacity, moderate thermal conductivity, low thermal diffusivity, and effective radiation shielding. These findings confirm that LBE obtained by the induction melting technique possesses the necessary structural stability and functional properties for integration into nuclear reactor and solar thermal technologies. Full article

Motivated by the growth of global energy demand and the goal of carbon neutrality, lead-cooled fast reactors, which are core reactor types of fourth-generation nuclear energy systems, have become a global research hotspot due to their advantages of high safety, nuclear fuel breeding capability, and economic efficiency. However, its engineering implementation faces key challenges, such as material compatibility, closed fuel cycles, and irradiation performance of structures. This paper comprehensively reviews the latest progress in the core design of lead-cooled fast reactors in terms of the innovation of nuclear fuel, optimization of coolant, material adaptability, and design of assemblies and core structures. The research findings indicate remarkable innovation trends in the field of lead-cooled fast reactor core design, including optimizing the utilization efficiency of nuclear fuel based on the nitride fuel system and the traveling wave burnup theory, effectively suppressing the corrosion effect of liquid metal through surface modification technology and the development of ceramic matrix composites; replacing the lead-bismuth eutectic system with pure lead coolant to enhance economic efficiency and safety; and significantly enhancing the neutron economy and system integration degree by combining the collaborative design strategy of the open-type assembly structure and control drums. In the future, efforts should be made to overcome the radiation resistance of materials and liquid metal corrosion technology, develop closed fuel cycle systems, and accelerate the commercialization process through international standardization cooperation to provide sustainable clean energy solutions for basic load power supply, high-temperature hydrogen production, ship propulsion, and other fields. Full article

Lead-bismuth eutectic (LBE) is a eutectic alloy of lead (44.5 at%) and bismuth (55.5 at%) that can be used as the coolant for the fast nuclear reactors. In the event of specific conditions or even accidents of the reactors, the temperature of liquid LBE decreases, and it may undergo solidification and volume expansion during the aging process after solidification, which can easily cause damage to the reactor’s internal structure as well as the reactor vessels. In this study, the microstructure and mechanical properties of solidified LBE obtained at different cooling rates are systematically investigated after different aging times. It was found that the internal structure of LBE after aging remained a eutectic microstructure, consisting of the γ-phase (Bi-rich phase) and β-phase (Pb₇Bi₃). After a long period of static aging, the white γ-phase precipitated into the black β-phase, which further confirms the phase transition mechanism. Meanwhile, the acceleration of the cooling rate can aggravate volume expansion. As the aging time increases, there is no significant difference in the compressive yield strength σ of the LBE samples with the same cooling rate and only a certain degree of fluctuation. The elastic modulus E also shows similar results, indicating that aging time has a minor effect on the compressive yield strength σ and elastic modulus E of the LBE. With the increase in cooling rate, the compressive yield strength σ shows an upward trend, while the elastic modulus E is not significantly affected, with a small amplitude of fluctuation. Meanwhile, the hardness of LBE samples after long-term aging treatment is enhanced. After long-term aging, the overall density of the LBE samples shows a decreasing trend, the density fluctuation range of the fast cooling rates (5 K/min and 10 K/min) are significantly larger than that of the slow cooling rates. The decrease in density leads to volume expansion of the LBE during the aging process after solidification. Full article

Lead–Bismuth Eutectic (LBE) is a very dense medium whose specific gravity is more than 10 times that of water. The unsteady hydraulic exciting force generated by the rotor–stator interaction (RSI) is significantly increased in the LBE pump, which has an important influence on the stable operation of the pump. The clearance between the vaned diffuser inlet and the impeller outlet has great influence on the rotor–stator interaction. This paper studies the unsteady flow characteristics in pumps with different rotor–stator clearance in different flow rates and transported mediums. The results show that at the design point, the head and efficiency of the pump when transporting LBE are 3.52% and 8.05% higher than those when transporting water. The pressure fluctuation distribution is similar at different positions inside the pump when transporting LBE and water, but the dimensionless pressure fluctuation coefficient is slightly larger when transporting water. The radial force in the pump shows a larger amplitude of 6BPF frequency with small clearance ratios, and the frequency is related to the guide vane number. When the clearance ratio increases from 1.03 to 1.13, the amplitude of 6BPF keeps decreasing. The amplitude at a clearance ratio of 1.13 decreased to 4.7% of that at 1.03. The research presented in this paper could provide some references for the design of the clearance between the rotor–stator parts in the LBE pump. Full article

Alumina-forming austenitic steels (AFA steels) exhibit excellent creep resistance and oxidation capabilities, making them a strong candidate for cladding materials in lead-cooled fast reactors. This study investigates the corrosion resistance of Mn-containing AFA steels in lead–bismuth eutectic (LBE) at 550 °C with a controlled oxygen concentration of 10⁻⁶ wt.%. The results demonstrate that under these experimental conditions, the addition of Al enhances the material’s resistance to lead–bismuth corrosion. Moreover, Mn incorporation significantly improves corrosion resistance, with the optimal composition being an AFA alloy containing 16 wt.% Ni, 12 wt.% Cr, 3 wt.% Al, and 4 wt.% Mn. Mn addition alters the type of oxide product formed on the alloy surface, shifting from Fe₃O₄ or (Fe, Cr)_xO_y to (Cr, Mn)_xO_y. Full article

In this study, slow strain rate tensile tests (SSRT) were performed on T91 in lead-bismuth eutectic (LBE) with saturated oxygen to investigate the effects of temperature (350 °C, 450 °C, and 550 °C), strain rate (1 × 10⁻⁵/s and 2 × 10⁻⁶/s) and pre-exposure conditions (time, oxygen concentration) on the sensitivity to liquid metal embrittlement (LME). The results revealed that the embrittlement sensitivity of T91 in LBE is significantly influenced by temperature. LME was observed in T91 at 350 °C and disappeared when the temperature increased to 550 °C. Additionally, T91 exhibited increased sensitivity to LME at low strain rates, indicating that low strain rates promoted the occurrence of LME. Finally, through different pre-exposure conditions, it was found that the obvious LME phenomenon would only occur when the oxygen concentration was poor and the pre-exposure time was long (48 h), indicating that pre-exposure conditions have a crucial impact on the occurrence of LME. Full article

A novel low-carbon 9Cr-ODS steel was exposed to corrosion in lead–bismuth eutectic saturated with oxygen at 500 °C for 1000 h, leading to the formation of three distinct layers of oxide film. From the outermost to the innermost layer, these included a Fe₃O₄ layer infiltrated with Pb, a FeCr₂O₄ layer, and an inner oxide zone. The inner oxide zone was primarily composed of an unoxidized matrix and Cr₂O₃. The formation of the inner oxide zone was primarily attributed to the preferential oxidation of Cr following the infiltration of insufficient O content. Two distinct morphologies of the inner oxide zone were identified: one is porous, while the other is non-porous. The porous morphology is characterized by low Fe content and Pb infiltration. The loss of Fe is the main factor contributing to the development of the porous inner oxide zone and the infiltration of Pb, while the short-range diffusion of Cr promotes the growth of Cr₂O₃, resulting in a needle-like morphology. Full article

With the advancement of lead–bismuth fast reactors, there has been increasing attention directed towards the design of and manufacturing technology for electromagnetic pumps employed to drive liquid lead–bismuth eutectic (LBE). These electromagnetic pumps are characterized by a simple structure, effective sealing, and ease of flow control. They exploit the excellent electrical conductivity of liquid metals, allowing the liquid metal to be propelled by Lorentz forces generated by the traveling magnetic field within the pump. To better understand the performance characteristics of electromagnetic pumps and master the techniques for integrated manufacturing and performance optimization, this study conducted fundamental research, development of key components, and the assembly of the complete pump. Consequently, an annular linear induction pump (ALIP) suitable for liquid lead–bismuth eutectic was developed. Additionally, within the lead–bismuth thermal experimental loop, startup and preheating experiments, performance tests, and flow-head experiments were conducted on this electromagnetic pump. The experimental results demonstrated that the output flow of the electromagnetic pump increased linearly with the input current. When the input current reached 99 A, the loop achieved a maximum flow rate of 8 m³/h. The efficiency of the electromagnetic pump also increased with the input current, with a maximum efficiency of 5.96% during the experiments. Finally, by analyzing the relationship between the flow rate and the pressure difference of the electromagnetic pump, a flow-head model specifically applicable to lead–bismuth electromagnetic pumps was established. Full article

With the increasing global demand for sustainable energy, the importance of advanced nuclear technologies, such as fourth-generation reactors, has become increasingly prominent. Fourth-generation reactors often use non-water coolants, among which liquid lead and lead–bismuth eutectics (LBEs) are highly promising, making lead-cooled fast reactors (LFRs) a popular area of research internationally. On the basis of extensive analysis and comparison conducted previously, this article summarizes and analyzes the advantages, problems, and differences in lead and LBE as LFR coolants. Overall, both lead and LBE have excellent neutronic characteristics, good heat transfer performance, and chemical inertness, and make LFRs highly efficient in nuclear fuel utilization, inherently safe, and relatively simplified in design. However, both of them corrode materials severely and produce highly toxic ²¹⁰Po, which are the problems that need to be considered for further engineering development. Moreover, LBE has a lower melting point, which allows a wider temperature range and lower insulation requirements in its design, making it easier to achieve engineering and miniaturization under the same conditions. Lead has a lower cost, is less corrosive to materials, and produces less ²¹⁰Po, which makes it a more ideal coolant for future development. Full article

Accelerator-driven subcritical (ADS) reactors with lead–bismuth eutectic (LBE) coolants are some of the Gen-IV nuclear energy systems that can generate clean electricity and potentially transmute spent fuel. The dynamic characteristics and control strategy of an ADS reactor are substantially different from those of traditional nuclear reactors. In this paper, a new collaborative control strategy is proposed using an accelerator beam and a control rod, and the control system’s parameters are optimized using a modified particle swarm optimization (PSO) method. To test the control performance, a simulation platform is developed with a nonlinear reactor dynamic model, a power compensation control system and a coolant temperature control system. Four typical control transients are used, including a ±10% full-power (FP) step change load and a ±5% FP/min linear variable load. The simulation results show that the collaborative control strategy has a better load tracking capability and a higher power control accuracy than the beam single-control strategy and the rod single-control strategy. The results also show that the performance of the collaborative control system in terms of the reactor’s power and coolant temperature is significantly improved based on the modified PSO parameter optimization. Full article

In this study, the stability of Cr₂O₃, ZrO₂, and Mn₃O₄ oxide films in high-temperature liquid lead–bismuth eutectic (LBE) was systematically investigated using both experimental and first principles calculation methods. The research findings indicated that Cr₂O₃ demonstrated superior structural integrity at corrosion temperatures of both 600 °C and 700 °C and displayed exceptional resistance to LBE corrosion. ZrO₂ demonstrates resistance to LBE infiltration. However, the emergence of cracks in the vicinity of the ZrO₂ layer and the metal interface undermines the protective layer’s integrity. Mn₃O₄ exhibits susceptibility to corrosion by LBE and lacks resistance to its effects. First principles calculations indicate that Pb and Bi atoms are most readily adsorbed onto the Mn₃O₄ surface, promoting the detachment of Mn atoms. The results show that the corrosion resistance of the three oxide films is ranked in the following order: Cr₂O₃ > ZrO₂ > Mn₃O₄. Full article

A CaO-MgO-Al₂O₃-SiO₂ glass–ceramic coating was prepared by the slurry method and subsequent sintering to improve the corrosion resistance of 316L steel in liquid lead–bismuth eutectic alloy at high temperatures. The glass–ceramic coating, sintered at 884 °C, was dense and demonstrated strong adhesion to the substrate. It was composed of the crystalline phases diopside (CaMgSi₂O₆) and anorthite (CaAl₂Si₂O₈) and had an average Vickers hardness of 595 HV, which was over three times that of 316L steel. After corrosion in an oxygen-saturated, static lead–bismuth eutectic alloy at 500 °C for 1000 h, the uncoated 316L experienced significant mass gain (0.04 g) due to severe oxidative corrosion, resulting in the formation of Fe₃O₄ and Pb₂O on its surface. In contrast, the glass–ceramic-coated specimens showed a very small mass gain (0.0012 g) after corrosion. The coating maintained good thermal stability; its crystalline phase composition remained largely unchanged after the corrosion test. The glass–ceramic coating still exhibited dense microstructure and tightly adhered to the substrate after corrosion. There was no evident penetration of lead–bismuth into the coating, and no dissolution of the coating’s elements into the lead–bismuth alloy was detected. These observations confirm that the glass–ceramic coating possessed superior corrosion resistance in liquid lead–bismuth eutectic environments. Full article