Small Modular Nuclear Reactor Research Articles

Neutronics Analysis of SMART Reactor Fuel Cell and Fuel Assemblies with Two Absorber Materials: Gd2O3 – UO2 and Al2O3 – B4C Using SRAC Code and JENDL 3.3 and 4.0 Data Libraries

The SMART is a small modular nuclear reactor which has been developed by South Korea’s KAERI, utilizes 4.95% enriched uranium fuel and two types of absorber materials: Gd2O3 - UO2 and Al2O3 - B4C. This research focuses on the neutronic analysis of SMART at the fuel cell and fuel assembly levels using SRAC 2006 with JENDL 3.3 and 4.0 Nuclear Data Libraries. The study aims to compare the neutronic performance of the SMART fuel assembly using these two absorber materials. At the fuel level, three types of enrichment are considered: 2.82%, 3.25%, and 4.95%. Meanwhile, at the fuel assembly level, three types (A, B, and C) are investigated, based on the composition of fuel rods and absorber material rods. The results indicate that the SMART reactor with the KAERI design (enrichment of 4.95% and 3 types of fuel assemblies) can maintain critical conditions for 990 days (equivalent to 3 years) of operation for small modular reactor types. The two types of absorber materials are effective in absorbing excess positive reactivity from the fuel effectively. The use of absorbing materials greatly determines the neutronic characteristics and costs in the construction of nuclear reactors, It can be compared that using 2 absorbing materials can reduce the value of the effective multiplication factor and the infinitive neutron production in the core compared to using 1 absorbing material.

Development of a hybridized small modular reactor and solar-based energy system for useful commodities required for sustainable cities

The current study develops a hybridized small modular nuclear reactor and solar-based system designed specifically for sustainable communities in metropolitan areas to meet their power, heat, clean fuel, fresh water and food requirements. Both floating-type and bifacial-type photovoltaic arrays are integrated with a high-temperature gas-cooled small modular reactor. In the integrated system, a Rankine cycle subsystem for power generation, a solid oxide electrolyzer for hydrogen production, a pressure swing adsorption unit with ammonia reactor for nitrogen and then ammonia production, a multi-effect desalination unit for freshwater generation, and heat recovery units in order to provide heating to residential area, food drying facility, greenhouse, and fish farm facilities. For both floating and bifacial PV options, the 120 MWp PV modules are considered and integrated with two small modular reactor units at 250 MWth capacities each, 500 MWth in total. A thermodynamic analysis, which is based on energy and exergy approaches, is carried out. The time-dependent analyses are carried out for floating-type PV and bifacial-type PV options for the cities of Istanbul in Turkey; Barcelona in Spain; Los Angeles (LA) in the United States; Tokyo in Japan; and Toronto in Canada by using their hourly meteorological data, source and load capacities in a typical meteorological year. Among ten cases, between 112835 and 146180 tonnes of ammonia are generated in a typical year while meeting the heating and power requirements of sustainable communities in metropolitan areas. Among ten cases, the average overall energy and exergy efficiencies are found as 41.04% and 46.88%, respectively. The hybridization of such nuclear and solar systems achieves unique advantages by preventing intermittencies compared to the renewable-alone systems, reducing carbon emissions compared to fossil-based systems, and lowering the levelized costs of energy compared to the nuclear energy-alone systems.

Assessing the cost competitiveness of electrolytic hydrogen production from small modular nuclear reactor-based power plants: A price-following perspective

Small modular nuclear reactor power plants (SMNRPPs) for hydrogen cogeneration are in early development, and their cost competitiveness for low-temperature electrolysis has not been well-studied. This study combines a quadratically-constrained economic dispatch model and a levelized cost analysis model to evaluate hydrogen cogeneration from a 300 MW SMNRPP coupled with proton exchange membrane electrolyzers. The SMNRPP adjusts its power output based on fluctuating electricity market prices and a time-invariant conversion value for electricity pricing arbitrage. We evaluated the SMNRPP-electrolysis system for 20 years in two case study locations and found the hydrogen supply cost ranged from CAD$1.77–3.36/kg and CAD$2.11–2.77/kg in electricity markets with high and low fossil fuel-dependence, respectively. The SMNRPP-electrolysis system is more cost-effective than fossil fuel-based hydrogen production at CAD$1.54/kg if the SMNRPP capital cost decreases to CAD$4,700/kW. This is because the SMNRPP capital cost accounts for 75% of the hydrogen supply cost variance, while other techno-economic parameters account for less than 27% of the supply cost variance. The system can achieve the lowest cost hydrogen production in under 17 years if the global learning rate and installation growth rates for SMNRPPs exceed 10% and 15%, respectively, to reach a 4.96 GW global footprint. The study outcomes can help formulate policies for SMNRPPs adoption in the hydrogen economy.

Dow nuclear reactor set for Texas

Dow has selected its petrochemical complex in Seadrift, Texas, as the site to install a small modular nuclear reactor system designed by X-Energy Reactor. The reactor will supply electricity and steam for the complex and will save about 440,000 metric tons of carbon dioxide emissions per year. The companies are now preparing permits for the Nuclear Regulatory Commission. They expect to begin construction in 2026 and complete the project by the end of the decade.

SMR, 3D source term simulation for exact shielding design based on genetic algorithm

One of the most important issue in the safe design of a small modular nuclear power reactor (SMR) is utilizing an efficient, compact, and lightweight radiation shielding capable of meeting the principal requirements of radiation protection. The radiation shielding design is a complicated multi-objective problem considering the current limitations. In this study, the three-dimensional and accurate modeling of the source term considering the real conditions of the reactor core has been performed and uses the genetic algorithm (GA) to improve the reactor radiation protection shielding system of SMR power reactors. The method upgraded in this research aims to reach an efficient design for the radiation shielding of the SMR power reactors regarding the present requirements and limitations. The thickness of different layers against the mixed-radiation fields of neutrons and gamma emitted from a nuclear reactor has been optimized to obtain a compact and lightweight shield design. The genetic algorithm coupled with the Monte Carlo Nth-Particle (MCNP) has been used for optimization. The shielding of a small modular reactor has been considered as a practical example and the reference for the calculations to evaluate and validate the developed technique and the thickness of different layers of radiation shielding has been optimized using the developed intelligent method. The shielding materials are identical to the original design, and optimization merely involves layer thickness values. Finally, considering the requirements and limitations, our design has been proposed, with a weight and volume comparison to the original design.The calculations indicate that the overall thickness of the shielding is suggested as 128.6 cm, compared to 153.7 cm the thickness of the reference to obtain the total dose of neutrons and Gamma less than 10µSv/h. The results imply a 20.9% reduction in volume and 19.35% in weight of the radiation shielding compared to the reference reactor design. It should be noted that unlike previous research, the present study used an optimization based on Monte Carlo calculations considering the real 3-D geometry of the reactor and its shield.

Review of Inaccuracies in the Analysis of the Flow Stability Specific of the LW-SMR Modular Design

The presented analysis has been issued to express doubts about the correctness of the engineering and operational safety assessment, which arises from the modeling of transient modes and methodologically should help light water small modular nuclear reactor designers/developers to correct the model they are usually creating for studying the stability of the thermal-hydraulic circuit of the light water small modular nuclear reactor with the natural circulation of primary coolant. After the NuScale report publication and the following presentation review, additional questions arise regarding the analysis methodology, which was carried out and presented as part of the licensing package presented to NRC. After having carefully and critically read the available part of the presented report on the study of instabilities and the presentation issued by NuScale, the answer to the NRC safety committee request could be concluded that the instability analysis has not been performed correctly not only technically, but theoretically. Some clarification of the problem of analysis of instabilities is required additional explanations for further integral light water small modular nuclear reactor design developments and correct analysis implementations.

Low-temperature nuclear heating reactors: Characteristics and application of licensing law in China

As one type of small modular nuclear reactor (SMR), the low-temperature nuclear heating reactors (LTNHRs), which have the characteristics of small size, a large power ratio, and good adaptability, can help provide energy in winter as well as reduce greenhouse gas emissions. Despite a growing number of LTNHRs worldwide, a mature legal regulatory system specifically targeting LTNHRs remains undeveloped. Further, few discussions have focused on the prospect of regulating LTHHRs and how national and international frameworks can respond to the new and increasing development of LTNHRs. Given the growing prominence of LTNHRs, this article aims to fill in the research gap by exploring possible regulatory pathways for LTNHRs and whether the existing nuclear regulatory frameworks developed for large reactors could be sufficiently applied to LTNHRs. The article examines and analyzes the prospects and potential challenges for regulating LTHHRs, specifically in the field of licensing. In particular, the article takes the Chinese nuclear legal system as an example to analyze whether the existing legislation and regulations can meet the new requirements for licensing of LTNHRs—given their unique characteristics—in China. Finally, this article proposes suggestions to address the obstacles to regulating LTNHRs, including amending the existing international regulatory framework, improving licensing supervision throughout environmental assessment and public participation, and strengthening international legal cooperation, to ensure the robust and reasonable development of LTNHRs worldwide.

Neural network extended state-observer for energy system monitoring

Due to the complexity of industrial energy systems such as the thermal power plants, renewable plants and batteries, energy system monitoring is gaining more and more attentions. Energy system monitoring methods give the estimations of internal process variables or parameters that can be adopted as the possible indicators for health conditions, which not only founds the basis for diagnosis and prognostics but also strengthens the situation awareness of system operators. In this paper, a neural network extended state-observer (NN-ESO) is newly proposed for general energy systems with measurements of key process variables, where the neural network adopted is the multi-layer perception (MLP). The advanced characteristics of this NN-ESO lies in the following three aspects: (1) No prior knowledge about the process dynamics is used in the observer design. (2) The globally bounded estimations of the exterior disturbances and their changing rates in the measurement channels can be provided. (3) The MLP in the NN-ESO is trained and deployed online without any offline training samples. By adopting the estimations of the exterior disturbances and their varying rates as the health indicators, the NN-ESO is applied for the operation monitoring of a modular high temperature gas-cooled reactor which is a typical small modular nuclear reactor. Simulation results show not only the satisfactory estimation performance but also the feasibility of applying NN-ESO for system monitoring.

Machine learning-driven energy management of a hybrid nuclear-wind-solar-desalination plant

The ongoing energy transition and incoming water scarcity crisis demand coordinated research to ensure a fossil-free future for humankind. Aiming to increase energy efficiency, reduce curtailment and decarbonize water production, this paper proposes a novel energy management system (EMS) for a hybrid plant compound by a small modular nuclear reactor acting as cogeneration unit, a wind and solar farms as generators. Additionally reverse osmosis and multi-stage flash desalination plants are included as demand responsive units along with a freshwater storage. Mixed integer linear programming (MILP) is employed to formulate this stochastic optimization problem, where piecewise linear functions define operational costs and efficiencies of SMR and desalination motivating energy efficiency and safety. Renewable availability point forecasts are obtained with physics informed machine learning models whose error is characterised by fitting the predictor's residuals to different statistical distributions following an unsupervised methodology. The suitability of the EMS is addressed in two study cases, one exploring the flexibility exploitation of the algorithm and another proving its suitability for real-time implementation. The dispatcher manages to keep unaltered the SMR's core reaction while satisfying both electrical and water demand in different renewable availability regimes by fully exploiting sector coupling flexibility. Simultaneously, renewable curtailment is kept to a minimum.

Numerical investigation of a plate-type steam generator for a small modular nuclear reactor

A numerical feasibility study was conducted to investigate the thermal–hydraulic characteristics of a steam generator with corrugated plates for a small modular reactor. Accordingly, a one-dimensional thermal–hydraulic analysis code was developed based on the existing state-of-the-art thermal–hydraulic models and correlations for corrugated plate heat exchangers. Subsequently, the pressure loss, heat transfer, and instability characteristics of the steam generator with corrugated plates were investigated according to the chevron angle and mass flux. Additionally, the characteristics of rectangular and disk-type corrugated plate steam generators with equivalent heat transfer areas were analyzed. The steam generator with disk-type corrugated plates exhibited better performance in terms of pressure loss and heat transfer rate than the rectangular type. In addition, when the mass flux decreased from the onset of boiling points, reverse gradients of the total pressure change were observed in both types. Thus, it was confirmed that Ledinegg instability could occur in the steam generator with corrugated plates. However, it was dependent on the chevron angle, and the optimal chevron angle to minimize instability was 45° under the conditions of the present analysis.

Design of the CAREM nuclear reactor core with dual cooled annular fuel and optimizing the thermal-hydraulic, natural circulation, and neutronics parameters

The small modular nuclear reactor (SMR) with annular fuel which is cooled internally and externally has the potential to maintain high power density with a sufficient safety margin. The benefit of the dual cooled annular fuel design is that heat can be transferred to the coolant from both the outer and inner surfaces.In this paper, design of the Argentina small modular reactor (CAREM) core with hexagonal assemblies using dual-cooled annular fuels with internal and external cooling is presented. Neutronics and thermal-hydraulic parameters are evaluated and analyzed by changing internal fuel radius. For this purpose, at the first, the dual-cooled annular fuel under clean and cold conditions is modeled and the effective multiplication factor has been calculated for different inner clad diameter. Indeed, the internal and external radius have been changed in such a way to maintain the reactor under moderated.Then, these annular fuels under full power conditions are modeled and power peaking factor has been calculated. Finally, natural circulation parameters are performed for a simulated fuel rod in the hot channel using computational fluid dynamics (CFD) simulation codes. These results are compared with the conventional CAREM reactor. One of the most prominent advantages of the annular fuels is the ability to make softer neutrons in which reduce maximum power peaking factor and improves fuel management and safety parameters in the reactor core.For data fitting, an artificial neural network is trained using the observed data. The input consists of different internal and external radiuses and output consists of fuel rods’ pitch, thermal-hydraulic and neutronic parameters. Finally, the optimal geometry of fuels is determined using the neural network by implementing the genetic algorithms.Indeed, developed Artificial Neural Network (ANN) utilizing the obtained data, predicts the thermal-hydraulic and neutronic parameters of the CAREM reactor core with dual-cooled annular fuels. Presented optimization algorithm, which has a significant ability to attain the best solutions, also determines the optimal values of natural circulation parameters (Vmax/Vavg, Vout-Vin, and pressure drops), heat transfer coefficients, MDNBR, RPPF, and excess reactivity of the reactor. Also, the designed artificial neural network and genetic algorithm has been validated using neutronic and thermal hydraulic calculations. Results indicate that by using annular fuels, better reactor safety and thermal efficiency are achieved.

Design of a new Small Modular Nuclear Reactor using TVS-2M Fuel Assemblies and Fuel Depletion analysis during the fresh-core cycle length

In this paper, a new fresh Small Modular Nuclear Reactor core with changes on the Fuel Assembly-type, fuel enrichment, and gadolinium (Gd) concentration of the Fuel Assemblies (FAs) is designed and proposed to improve and enhance the NuScale nuclear reactor as a typical PWR-Small Modular Reactor. An algorithm is additionally presented to redesign the core consisting of square lattice FAs into a core including hexagonal FAs. This algorithm is implemented based on the utilization of MCNP code which classifies the design criteria considering simplified modeling and complicated modeling with high computational cost. The algorithm is helpful for a designer to manage the computational cost of modeling during the design process.Core design Basis Limits including Neutronic and Thermal-hydraulics (TH) analysis, are performed and verified for the first cycle of the presented new Small Modular Nuclear Reactor as a Hexagonal NuScale (HNu). Via ANSYS-FLUENT& MCNP codes, TH and Neutronic analysis have been coupled. Also, the burnup calculations for the presented core have been done to analyze the core first cycle length. The excess reactivity and power peaking factor have been assessed during the first-cycle length. Average core fuel depletion has been taken into account, and masses of produced fission fragments and build-up of plutonium isotopes and the remaining mass of uranium isotopes (and Gd) have been computed at the end of the cycle (EOC).The presented new core (HNu) has the benefits of both the TVS-2M FA and NuScale. Compared to the NuScale, HNu has several advantages and superiority, such as increasing MDNBR, decreasing the maximum temperature of fuel and clad, more fuel burn-up, longer working cycle length, and decreasing the maximum power peaking factor.

Domain decomposition in the GPU-accelerated Shift Monte Carlo code

The GPU solver within the Shift continuous-energy Monte Carlo neutron transport code has been extended to provide domain decomposition in addition to domain replication to enable the solution of problems with memory requirements exceeding the capacity of a single GPU. The strategy follows the Multiple Set, Overlapping Domain (MSOD) approach that is used in Shift’s CPU solver and integrates into the event-based algorithm used for Shift’s GPU solver. Furthermore, the ability to assign processors to spatial domains non-uniformly has been maintained. Two different approaches for communicating particle data between domains are considered, and multiple criteria for load balancing problems have been investigated. Numerical results are presented for both fresh and depleted small modular nuclear reactor (SMR) cores. A parallel efficiency of approximately 80% was achieved with up to 16 spatial domains measured relative to full domain replication. A scaling study on the Summit supercomputer demonstrates a weak scaling parallel efficiency of over 90% on over 24000 GPUs.

Controllability of S-CO2 power system coupled small modular reactor with improved compressor design

• A larger backswept angle S-CO 2 compressor has steeper slope of pressure ratio and better surge margin. • A system with larger backswept angle compressor can apply inventory control for wider load range. • A system with larger backswept angle compressor has better performance at the low power level. A Supercritical CO 2 (S-CO 2 ) power cycle is one of the next generation power conversion cycles, which has many advantages originate from unique fluid’s characteristics near the critical point. Recently, a concept of small modular nuclear reactor (SMR) coupled with an S-CO 2 power cycle is proposed to target aggressively expanding SMR market. However, many components of S-CO 2 power cycle were designed with the experiences from the conventional fluids such as air and water. In this paper, in order to harness the full potential of the S-CO 2 power cycle by utilizing the fluid properties further, an S-CO 2 compressor with different characteristics from air compressor is evaluated in the viewpoint of system level. The analyzed compressor has a larger backswept angle in the impeller than the conventional compressor and this can be done due to the unique properties of S-CO 2 . A 10 MW scale SMR is selected to demonstrate the compressor’s effect on the system performance and control. As a result, S-CO 2 cycle with larger backswept angle compressor can be regulated by inventory control in a wider load variation because the system has low surging mass flow rate. Thus, the system with larger backswept angle compressor has 5.6% wider part-load performance range with inventory control alone than the system with conventional compressor.

Development and analysis of a polygenerational smart energy hub for sustainable communities

A new community based polygeneration smart energy system is proposed to meet the demands of a community in a sustainable manner and applied to case study where we aim to balance Ontario’s energy requirements while minimizing carbon emissions. In this case study, the smart energy hub utilizes a 30 MW small modular nuclear reactor which provides a unique and novel gas system at high temperature level integrated for the production and transportation of chemical energy; this occurs through a circuit in which an endothermic reaction (steam methane reforming plant) is connected to an exothermic reaction (methanation plant) and appears to be an attractive and preferable solution that meets the environmental requirements for a stable and efficient energy supply process. Complex multiscale subsystems are developed, modeled and simulated in the Aspen plus. Thermodynamic analyses on different sub-plants are presented, considering natural gas as the main feedstock, and incorporating power and heat production through chemical looping. The energy hub is capable of generating 10.8 MW of electricity and supplying 17.9 MW of heat for district heating. Hence, the overall energy and exergy efficiencies of the smart energy system are found to be 54% and 76% respectively. Also, a power to gas plant is integrated into the energy hub for the production of anhydrous ammonia with a capacity of 1816.22 tons/day and 100% carbon capture capabilities. Moreover, the impact of varying the input proportions of the system on the products and functionality of the energy hub are investigated.

On the inherent load following features of a small modular nuclear reactor

Small modular reactors (SMR) are deemed to largely participate in the midterm electricity production owing to their remarkable operational features. Among all, the coordinated employment of in-built design characteristics to procure enhanced safety and sustainability objectives is a key advantage. Inherent load following aspects of the NuScale integral design of SMRs will thus be explored in this work. To this end, a reasonably accurate coupled dynamic modeling platform is developed which accompanies the thermo-neutronic phenomena in the reactor core alongside with the heat transfer to the steam generator. Turbine leading (reactor following) operation is investigated as the load cycling strategy which largely relies on the role of thermal reactivity feedbacks in the reactor core to accommodate for the power demand scheduled from the turbine side. Comprehensive sensitivity analysis is conducted to figure out the opposing behavior of the fuel and coolant feedbacks in this regard. In line with the delaying act of the plant cold leg (connecting the reactor core and the steam generator), these results would help more appropriately occasion inherent load following features especially at the design stage, thus enabling more rapid load following scenarios in small modular reactors.

Are energy policies for supporting low-carbon power generation killing energy storage?

This paper explores the impacts of energy policies for supporting low-carbon infrastructure on the economic and financial performance of energy storage when coupled with a generator. The study sets in the UK context and the unit of analysis is the generator connected with energy storage. An analytical method is derived to assess the impact of policy schemes for low-carbon infrastructure on energy storage. The case study of energy storage systems coupled with a Small Modular nuclear Reactor (SMR) is quantitatively investigated in three scenarios: 1. SMR-only (the baseline); 2. SMR with thermal energy storage; and 3. SMR with Lithium-ion battery. For the strike price at 100 £/MWh, the net present value for scenarios 2 and 3 reduces from 562 M£ to 379 M£ and from 376 M£ to -1144 M£, respectively, when the energy storage capacity increases from 100 MWh to 1 GWh. As the net present value reduces with increased energy storage capacity (when coupled with generation), this work shows that low-carbon incentives are, unintentionally, barriers to the development of energy storage due to: (A) current generator incentives give a favourable return on investment and energy storage would diminish it; (B) energy storage cannot participate in generator only incentives.

Nuclear renewable hybrid energy system assessment through the thermal storage system

In support of the use of more efficient and low-carbon nuclear energy along with solar energy in power generation systems, the present paper presents a technical-economic analysis of a nuclear renewable hybrid energy system (NR-HES) case study for a given electricity and residential heat demand profiles of a typical remote community in Canada. The studied hybrid energy system is composed of a small modular nuclear reactor (SMR), a concentrated solar tower (CST), and a thermal energy storage (TES) unit. A fossil fuel backup energy source is also considered to generate excess electricity as needed. The CST and nuclear reactor both share the same TES system. Five different thermal storage fluids are examined: Therminol, Dowtherm, solar salt, Hitec salt, and Hitec XL salt. A transient thermodynamic mathematical model is developed in order to determine the overall configuration, performance, and operation strategy for the NR-HES. The operational strategy of the NR-HES is based on the steady-state full-power operation of the SMR, storing the excess energy in the TES system when the combined nuclear and solar power generation exceeds the power demand of the electrical grid and using the stored thermal energy during the periods of peak demand A detailed economic analysis of the NR-HES is conducted for each operational scenario, including the annualized cost of the TES system and the NR-HES plant, as well as annual revenue and profit generated by the TES system. The developed model is used to obtain the most economical thermal storage fluid and to optimize the size of TES system in order to minimize the use of fossil fuels and maximize profit. Parametric studies of reactor thermal power and CST's field area are conducted to determine their effect on the performance and configuration of the NR-HES. Based on the current case study in terms of demand profiles, the results revealed that Therminol is the most economical thermal storage fluid for the present NR-HES with a charging capacity and round-trip storage efficiency of 237 268 MWh/year and 96%, respectively. The optimum Therminol storage tank size is evaluated to be 14 m in height and 10 m in diameter with a yearly average power cycle efficiency of ~36% and economic profit of 1 158 30 CAD/year. The parametric studies indicated that a larger TES size may decrease the usage of fossil fuel energy sources; however, it increases system total capital cost and decreases the power cycle efficiency and TES profit at given load. The results of this study indicate that an NR-HES is a promising low-carbon power generation system with the potential to meet the electricity and residential heat demand of remote communities.

An option for integration of Carnot Battery into a small Nuclear Power Plant

This article proposes a combination of nuclear power plant and grid-scale energy storage, classified as Carnot battery. The electric heater heats molten salts when excess electricity is available in the grid. The steam that is produced in a small modular nuclear reactor is heated with hot molten salts in the external super-heater. For continuous superheating to be ensured, the plant is equipped with molten salt thermal energy storage. The combined plant and reference NPP are modelled and simulated at steady-state conditions. Due to the higher turbine inlet temperature, the efficiency of the combined generation-storage nuclear plant is substantially improved. The proposed concept makes the co-location of NPP and Carnot Battery more attractive than the separate plants. The integrated thermal storage acts as secondary electricity storage. As such, it surpasses compressed air storage and is competitive with the pumped hydro storage, in the absence of their geographical and environmental constraints.

Design of a Small Modular Nuclear Reactor with dual cooled annular fuel and investigation of the fuel inner radius effect on the power peaking factor and natural circulation parameters

Recently, a kind of fuel called “dual-cooled annular fuel” is used in the nuclear reactors, which allows the coolant to flow from the inside and outside of the fuel rod and finally causes a substantial increase in power density. The dual-cooled annular fuel rod has both inner and outer coolant channels. Also, Small Modular Reactors (SMRs) are the innovative design of nuclear reactors making remarkable interest during recent years. Since there is not enough available operating experience on SMRs, it might be possible to initiate extensive investigations on these types of reactors for the purpose of improving the current performance level of these systems, significantly.In this paper, for the first time, the core of a Small Modular Reactor (SMR) is designed based on the use of internally and externally cooled annular fuels. And then, neutronics and natural circulation parameters of this type of reactor are analyzed. For this purpose, at the first, the dual-cooled annular fuel under clean and cold conditions is modeled for the different inner clad diameter with same distance gap to gap of fuel rod and effective multiplication factor has been calculated. Then, these annular fuels under full power conditions are modeled for each inner clad diameter and power peaking factor has been calculated. Finally, natural circulation parameters calculations are performed for a simulated fuel rod in the hot channel using computational fluid dynamics simulation codes. These calculations are compared with a conventional NuScale reactor that does not use this kind of fuel. One of the most prominent of its advantages is the ability to moderate more of the neutrons in the reactor core with this type of fuel, which can increase the core effective multiplication, reduce total power peaking factor and improve natural circulation parameters. Increasing of the effective multiplication coefficient at cold and clean condition leads to increase the excess reactivity of the core which increases the operation cycle without refueling and it is useful from fuel management view-point. Also, it was found that by increasing the inner radius by more than 0.5 (cm), the power peaking factor increases, which is due to the more increasing of the pitch lattice relative to the mean free-path and excessive reduction of the mean power-density in the core and, also, increasing the flux gradient.