Search

The SMART (System-integrated Modular Advanced ReacTor) is an integral-type small modular reactor developed by KAERI (Korea Atomic Energy Research Institute). This paper discusses the feasibility and applicability of a 3D-based equivalent model using dynamic condensation method for seismic analysis of a SMART control rod drive mechanism. The equivalent model is utilized for complicated seismic analysis during the design of the SMART. While the 1D-based beam–mass equivalent model is widely used in the nuclear industry for its calculation efficiency, the 3D-based equivalent model is suggested for the seismic analysis of SMART to enhance the analysis accuracy of the 1D-based equivalent model while maintaining its analysis efficiency. To verify the suggested model, acceleration response spectra from seismic analysis based on the 3D-based equivalent model are compared to those from the 1D-based beam–mass equivalent model and experiments. The accuracy and efficiency of the dynamic condensation method are investigated by comparison to analysis results based on the conventional modeling methodology used for seismic analysis.

Hybrid energy systems with small modular reactors (SMRs), a fast emerging nuclear power plant technology, and renewables hold a significant promise for the development of clean energy systems. This paper proposes a model of SMR based hybrid energy system for electricity and district heating (DH) with a detailed dynamic model of the reactor and a quasi-static model of the DH system in Siemens PTI PSS/E and PSS/Sincal. A multi-time scale approach, separating the load following and frequency regulation operation, is proposed to assess the flexible operation in the presence of highly intermittent renewable energy sources (RESs). A portion of a modified IEEE 30-bus system network is used as a test system for an isolated community for simulating the proposed hybrid energy system, and comparative results are shown to demonstrate the potential benefits of the DH system, thermal energy storage, and the electrical energy storage to the SMRs flexible operation.

Cogeneration coupling of the small modular reactor (SMR) based nuclear power plant (NPP) with district heating (DH) system enhances SMRs ability to provide flexible operation. The coordinated reactor control and DH steam extraction can fulfill the load following requirements, while the battery energy storage system (BESS) and the steam bypass system can absorb the short term disturbances, allowing the system to host renewable energy sources (RESs) such as wind and photovoltaics (PV). This paper develops an optimal operation framework for the SMR-RES hybrid energy system for electricity and DH and demonstrates the proposed scheme using a portion of the IEEE-30 bus system. The simulation results from a set of studies are provided to demonstrate the load following (LF) and frequency regulation (FR) operation for a month-long period. The operational results for different RES hosting levels are analysed, evaluating the optimum size of wind and PV plants for the proposed system. The results show that the proposed hybrid energy system is feasible as a stand-alone system and can optimally host as high as 50% renewables.

An integral test facility, PILLAR, was commissioned, aiming to provide valuable experimental results which can be referenced by system and component designers and used for the performance demonstration of liquid-metal-cooled, passive small modular reactors (SMRs) toward their licensing. The setup was conceptualized by a scaling analysis which allows the vertical arrangements to be conserved from its prototypic reactor, scaled uniformly in the radial direction achieving a flow area reduction of 1/200. Its final design includes several heater rods which simulate the reactor core, and a single heat exchanger representing the steam generators in the prototype. The system behaviors were characterized by its data acquisition system implementing various instruments. In this paper, we present not only a detailed description of the facility components, but also selected experimental results of both steady-state and transient cases. The obtained steady-state test results were utilized for the benchmark of a system code, achieving a capability of accurate simulations with ±3% of maximum deviations. It was followed by qualitative comparisons on the transient test results which indicate that the integral system behaviors in passive LBE-cooled systems are able to be predicted by the code.

This paper presents the computational fluid dynamics (CFD) validation and scaling assessment of the condensation heat transfer (CHT) models in the presence of non-condensable gas for the passive containment cooling system (PCCS) of the small modular reactor (SMR). The STAR-CCM+ software with 3D scaled-down SMR containment geometries was used in CFD simulations with steam and non-condensable gas (NCG). The limitations and approximations of the previous studies were resolved to avoid scaling distortion and uncertainties. Air was used as the NCG gas with steam. The multi-component gas model was used to define the steam-NCG mixture, and the condensation-seed parameter was used as the source term for the fluid film model. Three different turbulence models were used to check the heat flux performances and temperature distributions on the coolant side. The heat flux was estimated from the axial coolant bulk temperature, which was identical to the test data reduction method. An implicit-unsteady numerical solver was applied to the conjugate heat transfer models between the gas, liquid, and solid regions. Detailed simulations were performed, and simulation results were validated with the measured parameters experimentally. The condensation heat transfer performance was quantified using non-dimensional numbers and compared for different scaled geometries to identify the scaling distortions.

In this study, lattice physics calculations were carried out to evaluate the reactor physics characteristics of different advanced fuel lattices cooled with 7LiOH/NaOH or FLiBe and moderated extern...

Small modular reactors (SMRs) are currently framed as a clean energy innovation with a vital role to play in decarbonizing power production. We review two popular sustainability transitions framewo...

Small modular reactors (SMRs) are suitable for deployment in isolated underdeveloped areas to support highly localized microgrids. In order to achieve almost autonomous operation for reducing the cost of operating personnel, an autonomous control system with decision-making capability is needed. In this paper, a decision-making method based on Bayesian optimization algorithm (BOA) is proposed to explore the optimal operation scheme under fault conditions. BOA is used to adjust exploration strategy of operation scheme according to observations (operation schemes previously explored). To measure the feasibility of each operation scheme, an objective function that considers security and economy is established. BOA attempts to obtain the optimal operation scheme with maximum of the objective function in as few iterations as possible. To verify the proposed method, all main pump powered off fault is simulated by RELAP5 code. The optimal operation scheme of the fault is applied, the transient result shows that all key parameters are within safe limits and SMR is maintained at relatively high power, which means that BOA has the decision-making capability to get an optimal operation scheme on fault conditions.

A detailed computational fluid dynamics (CFD) simulation analysis model was developed using ANSYS CFX 16.1 and analyzed to simulate the basic design and internal flow characteristics of a 180 MW small modular reactor (SMR) with a natural circulation flow system. To analyze the natural circulation phenomena without a pump for the initial flow generation inside the reactor, the flow characteristics were evaluated for each output assuming various initial powers relative to the critical condition. The eddy phenomenon and the flow imbalance phenomenon at each output were confirmed, and a flow leveling structure under the core was proposed for an optimization of the internal natural circulation flow. In the steady-state analysis, the temperature distribution and heat transfer speed at each position considering an increase in the output power of the core were calculated, and the conceptual design of the SMR had a sufficient thermal margin (31.4 K). A transient model with the output ranging from 0% to 100% was analyzed, and the obtained values were close to the Thot and Tcold temperature difference value estimated in the conceptual design of the SMR. The K-factor was calculated from the flow analysis data of the CFX model and applied to an analysis model in RELAP5/MOD3.3, the optimal analysis system code for nuclear power plants. The CFX analysis results and RELAP analysis results were evaluated in terms of the internal flow characteristics per core output. The two codes, which model the same nuclear power plant, have different flow analysis schemes but can be used complementarily. In particular, it will be useful to carry out detailed studies of the timing of the steam generator intervention when an SMR is activated. The thermal and hydraulic characteristics of the models that applied porous media to the core & steam generators and the models that embodied the entire detail shape were compared and analyzed. Although there were differences in the ability to analyze detailed flow characteristics at some low powers, it was confirmed that there was no significant difference in the thermal hydraulic characteristics' analysis of the SMR system's conceptual design.

Over the course of the last several years the Canadian Nuclear Safety Commission (CNSC) has engaged with numerous vendors and potential licenses of small modular reactor (SMR) technology. This paper discusses what an SMR is and what potentially makes them different from standard nuclear power plants (NPP). Readiness activities for the potential licensing of SMRs are described as well as modifications being made to the CNSC’s existing regulatory framework to facilitate the same, without reducing safety. The role of the CNSC’s discussion paper DIS-16-04, Small Modular Reactors: Regulatory Strategy, Approaches and Challenges (DIS 16-04) and how feedback received on it helped confirm the CNSC’s modifications to be undertaken to the regulatory framework, as well as areas requiring further clarity, are highlighted. Finally, the role of the CNSC Vendor Design Review process is described as well as other readiness activities undertaken by the CNSC that are helping to ensure that the CNSC will be ready to accept and evaluate a license application for an SMR.

The SMART (System-integrated Modular Advanced ReacTor) is an integral-type small modular reactor developed by KAERI (Korea Atomic Energy Research Institute). This paper discusses the development of a dynamic equivalent model of the SMART control rod drive mechanism that can be efficiently utilized for complicated analysis during the design of the SMART. A semi-empirical approach is used to develop the equivalent model; that is, the equivalent model is defined analytically and verified empirically. Two types of tests, dynamic characteristics tests and seismic loading tests, are conducted for the development and verification of the dynamic equivalent model, respectively. Acceleration response spectra from the seismic analysis based on the developed equivalent model show good agreement with those from the seismic loading tests.

One of the barriers on the implementation of nuclear energy in Indonesia is public perception towards the safety of nuclear power plants (NPPs). Therefore, it is necessary to perform a study about the radiation impact of normal and abnormal operations of an NPP. In accordance to the program of Ministry of Research and Technology period 2020-2024, concerning the plan to build a small modular reactor (SMR)-type NPP, a radiation safety study has been performed for the 100 MWe Pressurized Water Reactor (PWR-100MWe). Source term release of radioactive substances into the environment from PWR-100MWe is a starting point in the study of the radiological consequences of reactor operation. Therefore, this paper will examine the PWR-100MWe source term under normal and abnormal operating conditions, according to the design and the design basis accident (DBA). The initial trigger of the DBA is Lost of Coolant Accident (LOCA) such as Small LOCA and Large LOCA. Due to the limitations of available SMR data, the study of PWR-100MWe source term refers to the assumption of the release fraction of fission products per subsystem in a larger 1000MWe PWR. It is expected from this assumption that pessimistic source term will be obtained. The study begins with calculation of PWR-100MWe core inventory using ORIGEN2 code based on PWR-100MWe reactor parameters. Through the mechanistic source term model and PWR-1000MWe release parameters, source terms will be obtained for normal operation and abnormal conditions i.e. DBA. Normal source term is used to calculate the consequences of normal operation, which will be used for environmental monitoring and environmental safety analysis of the site. Whereas accident source term is the basis for calculating the radiological consequences of accidents used for SAR documents and nuclear preparedness.Keywords: SMR, PWR-100MWe, normal operation, source term, accident

This paper provides information on the issues that impact the adoption of Small Modular Reactors (SMR) in microgrids as additional resources. It summarizes the technical and economic characteristics and financial model cases. It also discusses technical issues related to SMR installations and their operation and control in load following and frequency regulation.

Some energy consumers require power on an anytime, all-year-round basis with a high level of certainty, including defense installations, isolated communities, and some industrial processes. For the...

Canada has attracted specific interest from developers of nonwater-cooled small modular reactor (SMR) technologies, including concepts based on high-temperature gas-cooled reactors (HTGRs). It is anticipated that some research and development (R&D) will be necessary to support safety analysis and licensing of these reactors in Canada. The Phenomena Identification and Ranking Table (PIRT) process is a formalized method in which a panel of experts identifies which physical phenomena are most relevant to the reactor safety analysis and how well understood these phenomena are. The PIRT process is thus a tool to assess current knowledge levels and (or) predictive capabilities of models, thus providing direction to a focused R&D program. This paper summarizes the results of a PIRT process performed by a panel of experts at Canadian Nuclear Laboratories for a limiting or “worst-case” accident scenario at a generic HTGR-type SMR. Suggestions are given regarding the highest priority R&D items to support severe accidents analysis of these reactors.

A rapid build-out of direct air capture (DAC), deployed in order to mitigate climate change, will require significant amounts of both low-carbon thermal and electrical energy. Firm low-carbon power resources, including nuclear, geothermal, or natural gas with carbon capture, which also will become more highly valued as variable renewable energy penetration increases, would be able to provide both heat and electricity for DAC. In this study, we examined the techno-economic synergy between a hypothetical DAC plant in the year 2030 and a nuclear small modular reactor, and determined two avenues for which this relationship could benefit the nuclear plant. First, we demonstrated that, under certain assumptions, selling a portion of its energy to a DAC facility allows the nuclear plant to take in 21% less revenue from selling electricity to wholesale markets than its projected levelized cost, and still break even. Second, after estimating a potential revenue stream, we showed that an integration with DAC allows for the nuclear plant's capital costs to be up to 35% higher than what would be required if only selling electricity to wholesale markets. This could enable the nuclear plant to operate economically even in the face of variable and decreasing wholesale electricity prices, and also could offer developers more financial certainty when planning a new project. Ultimately, this study shows that the need for low-carbon energy for DAC plants might incentivize the development of advanced nuclear plants and firm low-carbon resources more broadly.

In this research, we focussed on producing nuclear products through the most rapidly growing technology, “additive manufacturing (AM)”. AM has successfully entered almost all manufacturing industries as this is the most reliable technology for producing products efficiently and on time. When we look towards the nuclear industry, the need to efficiently manufacture complex nuclear products can be successful through AM. In nuclear industries, there are many other spare components. Through the AM, the time for manufacturing for those products deducted by almost 90%. The cost-saving factor of AM helped nuclear industries in many ways. By producing a small modular reactor by AM technology, the cost and time can be cut significantly. Many products like impeller, thimble plugging device, pressure vessels, and boiling water reactor lower tie plates. Many big industries are also looking for manufacturing of the reactor core. That will be the game-changer. As the products manufactured would be used in nuclear industries, the material needs to be very durable, rugged and sturdy. Many researchers are still developing such materials to withstand the immense aggressive environment of the reactor. Different materials are already in action, which is a mixture of different properties. Addbor N25 is specially developed such that it can withstand radiation without failure. It is made through a combination of boron carbide and nylon. Boron carbide is one of the most complex materials present. Silicon carbide can also be seen for the production of other spare parts. Different factors are also considered for selecting material like geometrical tolerance, mechanical properties, chemical composition, and behaviour towards corrosion, hardness and friction. Many old nuclear industries also face the problem that the complex parts they have manufactured through old manufacturing techniques cannot manufacture through the same technique as they would not give the desired configuration. Here AM becomes majorly helpful by the production of the product with exact configuration through reverse engineering. We considered all the available materials through this research and studied all the properties and the possible product that can be formed.

In this paper, the conceptual design and a preliminary study of the LUT Heating Experimental Reactor (LUTHER) for 2 MWth power are presented. Additionally, commercially sized designs for 24 MWth and 120 MWth powers are briefly discussed. LUTHER is a scalable light-water pressure-channel reactor designed to operate at low temperature, low pressure, and low core power density. The LUTHER core utilizes low enriched uranium (LEU) to produce low-temperature output, targeting the district heating demand in Finland. Nuclear power needs to contribute to the decarbonizing of the heating and cooling sector, which is a much more significant greenhouse gas emitter than electricity production in the Nordic countries. The main principle in the development of LUTHER is to simplify the core design and safety systems, which, along with using commercially available reactor components, would lead to lower fabrication costs and enhanced safety. LUTHER also features a unique design with movable individual fuel assembly for reactivity control and burnup compensation. Two-dimensional (2D) and three-dimensional (3D) fuel assemblies and reactor cores are modeled with the Serpent Monte Carlo reactor physics code. Different reactor design parameters and safety configurations are explored and assessed. The preliminary results show an optimal basic core design, a good neutronic performance, and the feasibility of controlling reactivity by moving fuel assemblies. Publishers version

The nuclear industry is entering into a generation in which Small Modular Reactors (SMRs) could provide solutions to the worlds future energy needs. New technology and operations will be associated with new Human Factors (HF) design challenges. Operators may be faced with a higher cognitive workloads while monitoring several reactor units at once from a central main control room (MCR), or when monitoring units remotely. Automated processes may be implemented to mitigate human error, however may also result in a reduced sense of operator awareness in situations where operators fail to develop an accurate mental model of plant status. The present article highlights design recommendations that should be considered during the early stages of SMR MCR design to optimize human performance. Also discussed is the potential applications of eye tracking, and virtual reality (VR) to inform designers on best practices in display design and control room environments, respectively.

Small modular reactors (SMR) are in great demands in the near future and the lead-based fast reactor is one of the most important directions in the development of SMR. In this paper, core design and analysis of a LEad-bismuth Small MOdular Reactor (LESMOR) was developed and examined to realize the notion of “LESS is MORE”. LESMOR is a 300 MWt pool-type reactor where all facilities are mounted in a reactor vessel. Advanced nitride fuel is adopted, and the spent-plutonium is used as the driven fuel and thorium is used as the fertile fuel. Sub-channel analysis was performed in the assembly design using an in-house sub-channel code SUBAS, and the 11 × 11 scheme with a pitch-to-diameter (P/D) ratio of 1.4 was adopted. The full core neutronic performance was studied and evaluated in this paper. Results show that the reactor can be maintained critical for 20 years and the maximum radial power factor is 1.28. The steady-state thermal-hydraulic performance of the core was analyzed, including the characteristics of the mass flow distribution and the hottest assembly. The peaking fuel cladding temperature is 519.2 °C, and the maximum fuel center temperature is 723.4 °C, both within the temperature limit. This paper provides valuable information in the neutronic and thermal-hydraulic design and analysis of LBE nuclear reactor.

The NuScale Small Modular Reactor (SMR) is premised on well-established nuclear technology principles with a focus on integration of components, simplification or elimination of systems, automation, and use of passive safety features. Traditional nuclear power plants have in some cases operated up to four modules from a single control room. Due to the unique nontraditional operating characteristics of this technology a state-of-the art control room design was needed to ensure proper staffing totals for monitoring and control of multiple modules (twelve) from a single control room. To accomplish this, the human system interface and control room layout must translate the functional and task requirements needed for safe operation of the plant into the detailed design of workstations, alarms, controls, navigation, and other needs of the control room operations staff.

This work presents the safety-related neutronics and thermal-hydraulics features of a reactor core designed to fit into a Small Modular Reactor (SMR) moderated and cooled by light water. The core design process is conducted in an iterative manner to optimize its performance from safety perspective. The optimized core is operated without boron in the moderator and is characterized by enhanced safety features as a result of (1) avoiding concerns related to boric acid induced corrosion of a reactor pressure vessels internals; and (2) eliminating the probability of boron dilution accidents. The optimization studies are performed with an advanced multi-physics simulation tools including both neutronics (deterministic, Monte Carlo) coupled with a subchannel thermal-hydraulics code. With an intensive core design iteration process and through using such multi-physics tools, a reactor core with sufficient thermal margins, a cold shutdown margin, and a reduced power peaking factor is obtained. In this paper, the core design approach, core features, and the verification of the core analysis method are discussed in details. Finally, it has been concluded that the developed and optimized core fulfills all safety requirements and design objectives.

When the small modular reactor (SMR) operates off-grid, the load following demand increases. To solve this problem, a flexible load is used to compensate the electricity load. The flexible load comprises power-consuming systems that can change their load actively, such as district heating, desalination, hydrogen production, and other industrial heat supply systems. Based on the modeling of the nuclear steam supply system, turbine, and flexible load, a simulation platform is established in the MATLAB/Simulink environment. For the load following to be compensated by the flexible load, the key problem is dynamic load allocation, in which the electricity load is divided into a moderate part and fluctuating part. The two parts of the load are undertaken by the SMR and flexible load, respectively. Based on the characteristics of different flexible loads, the changeable flexible load and fluctuating flexible load are presented. Two load following control methods are presented for the two types of flexible loads. The simulation results show that the present method can not only relieve the load following burden of the reactor core but also provide steam with stable quality to the flexible load, thereby improving the flexibility and efficiency of the SMR.

An ex-vessel–type control element drive mechanism (CEDM) is installed on the nozzles of a reactor vessel closure head. However, there has been a demand for locating CEDMs inside the reactor...

At present, no clear guidelines exist for modeling non-water-cooled small modular reactors (SMRs) despite the rising need for high-fidelity simulation tools to support regulators and the industry. ...

Small Modular Reactor (SMR) is a small, compact version of a conventional Nuclear Power Plant (NPP) and holds much promise for the future. Installing SMRs in a region requires a series of carefully planned steps out of which site selection is a critical one. This paper proposes a novel mathematical model for evaluating potential land sites for their suitability of hosting a modular NPP. Most existing decision making tools for NPP site selection rely on qualitative information from the experts. These tools require significant resources and therefore can only be applied to a limited number of selected sites. The proposed model is a Mixed Integer Non-linear Programming (MINLP) formulation which considers a variety of factors like cost, cooling water availability, earthquake risk, etc. to identify best locations for the SMRs in a distributed power system. A case study based on a virtual EIP simulator is conducted to demonstrate the capabilities of the model by finding the optimal locations of modular NPPs. The model offers a preliminary platform for carrying out further extensive studies.

Fully ceramic micro-encapsulated (FCM) fuel has high thermal conductivity and fission product retention capabilities. It can improve the accident tolerance ability of light water reactors (LWRs). Small modular reactors (SMRs) shows a good inherent safety due to their good design and low power density. Combining FCM fuel and SMR may greatly improve the safety of the reactor. In this paper, a SMR model using FCM fuel is built by referring to the Westinghouse Small Modular Reactor (WSMR). Based on this model, we analyzed some accidents associated with SMR using FCM fuel and compare this information with SMR using UO2 fuel. The results indicate that the steady running temperature of FCM fuel is low and that the temperature increases slowly in accidents. The SMR using FCM fuel has good safety features and delay the melting of the core. Under the conditions of station black-out (SBO) combined with failure of core makeup tanks (CMTs) and ADS automatic depressurization system (ADS), the failure time of the core using FCM fuel is 5.49E4 s, which is 7.10E3 s (1.97 h) longer compared with that of UO2 fuel. When considering reinvestment in CMTs, the time limit of FCM fuel is 1.33E4 s (3.70 h) longer compared with that of UO2 fuel, which offers enough time for the restoration of safety system in the accident state. Because of its low temperature, the hydrogen production rate of FCM fuel is reduced compared with that of UO2. However, given the use of zirconium cladding, the final output of hydrogen is the same as or even more than UO2 fuel, and hydrogen elimination devices must be considered.

Small modular reactor (SMR) is a type of advanced reactor depending on its inherent safety, good economic performance, and multipurpose. SMR always adopts the multi-modular layout, which uses several nuclear steam supply systems (NSSSs) to supply steam to a common steam header. A pressurized water reactor (PWR) type multi-modular SMR (MSMR) system is studied in this paper. Due to the operation demands of continuity and flexibility during load following, a proper control strategy and operation scheme of the MSMR must be investigated. A master-slave control strategy is proposed for steam flow sharing control of the MSMR systems. Under the proposed control strategy, one of the NSSS modules is selected as the master control channel, and its feed water flow rate is regulated using the steam header pressure error. The remaining NSSS modules are treated as the slave channels. The feed water flow rate of the master channel is utilized to slave the other channels, which are flow-controlled. Three operation schemes are set according to different operation demands. (1) Equilibrium Scheme (EquS), in which every module undertakes the same load during the load following operation. (2) Non-equilibrium Scheme (NEquS), in which every module undertakes the different loads during the load following operation. This operation scheme manages more modules operate at full power to ensure its economy and operation simplicity. (3) Constant Output Scheme (ConS), which is mainly used during refueling or maintenance process. When one module is disturbed, other modules undertake its load to ensure the total power output constant. Based on these schemes, four typical operation cases are defined and simulated. Through the analysis of the simulation results, the suitable operation conditions for these operation schemes are suggested, and the relevant control strategy is verified.

There has been a steady growth of interest in the technology of small modular reactors (SMR) in the world recently. SMRs are considered as a promising area for the further development of nuclear industry. The paper defines the term “small modular reactor”, presents the scope, potential advantages and disadvantages of SMR. A review was made and a classification of SMR projects was proposed depending on the novelty of their technical solutions. The paper presents an enlarged comparative analysis of individual SMR technical solutions (based on the example of Holtec International SMR-160) with operating Ukrainian NPPs to identify peculiarities of SMR that should be addressed in licensing. Certain specific design solutions of SMR-160 are correlated with defense-in-depth levels. The approaches and condition for licensing SMR designs in the international practice are analyzed. The paper identifies problematic aspects with regard to regulatory framework and confirmation of the efficiency of SMR design solutions, as well as formulates proposals and recommendations for the first steps to ensure the licensing process in response to the initiative of the operating organization Energoatom.

This article investigates a high temperature prismatic core small modular reactor concept based on the U-Battery. To achieve a long operational time without reloading of the fuel, a high fissile fuel load is required, to provide the required excess reactivity which needs to be compensated to allow safe operational states in all stages of the life of the core. This is achieved through the means of reactivity control methods. In this article we deploy a design methodology for controlling the reactivity in a design based on the U-Battery. The initial excess reactivity within the core was 2000 pcm, implying that the reactivity control systems were required to bring this to unity. To reduce this reactivity, we investigated three main reactivity control methods. Initially the control rod designs which is kept constant. Then a full range of fixed burnable poison designs are evaluated. The final reactivity control method investigated the process of flux spectrum hardening by changing the moderation within the core. This work managed to identify that maximum full power days without any reactivity control as 1364 days. The fixed burnable poisons deployed reduced this lifetime by 62 days due to a reduced neutron economy. However, by removing part of the central reflector the flux spectrum hardens (increases the proportion of fast neutrons) this provides additional bred plutonium provided an additional 62 full power operating days. The meant that the overall design saw no lifetime reduction due to reactivity control devices, without including the use of control rods. Due to the implemented reactivity control systems, the highest point of reactivity has been identified as 1.03, this meant that the control rod position required to reduce this reactivity is limited to the maximum of 50% insertion. Identifying the power profile at this position showed additional loading at the fuel below this point, where additional thermal distribution work will be undertaken.

Nuclear power can solve the energy trilemma of supplying baseload, clean and affordable power. However, a review of nuclear power plant (NPP) builds show mixed results, with delays in Finland and in the US offset by successes in China, South Korea and the UAE. In the West, financing for new builds has been difficult in the face of a deregulated energy market, billion-dollar upfront investments, long build times and in the case of the US historically low gas prices. We explore how the nuclear industry is innovating in facing these challenges through a review of nuclear power developments in the past, present and future. Early developments in nuclear power in the 1950s resulted in a variety of designs, out of which the pressurised water reactor (PWR) became dominant for its compactness and overall economy. Over the next 10 years, several PWR-based small modular reactor (SMR) designs are expected to come online within an eight-year timeframe. Their modular construction and fabrication in a controlled factory setting aims to shorten build times from 8 to 3 years. However, the lack of established regulatory approval pathways may be a time-limiting challenge that needs to be overcome by the first fleet of SMRs. The passive safety and a smaller fuel loading of SMRs will allow them to be deployed at more potential sites, including brownfield replacements of old coal-fired power plants or power unconventional, remote or islanded grids. Some SMRs are also designed to load follow which will allow them to work harmoniously with intermittent renewables sources with the promise of an affordable, truly carbon-neutral grid. In the longer term, advanced nuclear reactors in the form of sodium cooled, molten salt cooled, and high temperature gas cooled reactors hold the promise of providing efficient electricity production, industrial heat for heavy industry as well as the generation of hydrogen for synthetic fuel.

The Small Modular Reactor (SMR) concept is designed such that it will solve some of the construction problems of large reactors. SMRs are designed to be “shop fabricated and then transported as modules to the sites for installation” (IAEA, 2018). As a consequence they theoretically have shorter build schedules and require less capital investment (Locatelli et al., 2014). Factory built modules can also increase safety and productivity, due to higher quality tools and inspection available. A literature review has highlighted substantial work has been undertaken in the research, development and construction of different types of reactors and reactor modules but the design of balance of plant modules has not been extensively researched (Wrigley et al., 2018). The focus of this paper is a case study for balance of plant modules in a light water reactor which also could have applications to other reactor types. Modules that are designed for factory build and transport may be built in a standardized module approach. By maximizing module size for transport, this maximizes work offsite, to achieve the cost and schedule savings associated. A design method needs to be developed to help support this approach. To enable this, a three step method is proposed: group components into modules, layout the modules and arrange components inside the modules. The Shearon Harris nuclear power plant was chosen for its publically available data. A previous study on this plant used matrix reordering techniques to group components and heuristically assign them to large modules, built for construction in an assembly area on site, highlighting a potential capital cost savings of 15%. This paper utilizes the same allocation of components to modules as the previous study but aims to undertake the challenge of how balance of plant modules should be arranged. The literature review highlighted that although the facility and plant layout problem has been extensively researched, mathematical layout optimization has not been applied to nuclear power plants. Many techniques for layout optimization have been developed for facilities and process plants however. The work in this paper develops an optimization model using a genetic algorithm for module layout and allocation within a nuclear power plant. This paper analysed two configurations of modules, where balance of plant modules are located on either one or two sides of the nuclear island. The objective function was to minimise pipe length. In the original research, where the plant was configured for assembly on site, the balance of plant modules are located around three sides of the nuclear island. The objective function was calculated at 14,914. As the distances are calculated rectilinearly, this number would be higher in reality as pipework has to be routed around containment. The optimization reduced the objective function by 33.9% and 37.8% for the three and four floor layouts respectively when balance of plant modules are located on two sides of the nuclear island. Furthermore, when modules are located on one side of the nuclear island, the objective function was reduced by 45.4% and 46.1% for three and four floor layouts respectively. This will reduce materials used, reduce build time and hence reduce the cost of a nuclear power plant. This method will also save design time when developing the layout of modules around the plant.

It has been argued that risk and performance-based approaches to licensing would be appropriate for Small Modular Reactors (SMRs) because their risk profiles differ from large-scale reactors. This is based on several factors including their limited electrical capacity of 300 MW, the below grade reactor vessel, and passive safety features. One design feature that can significantly reduce accident severity is the larger lateral surface area-to-volume (A/V) ratio of SMRs. Following a nuclear accident, this larger A/V ratio can increase the removal of radioactive particles due to natural phenomena compared to large light water reactors (LWRs). To quantify the improvements in safety, this work estimates the airborne radioactivity within containment and environmental dose exposure in a post-accident scenario for an advanced Generation III+ LWR (AP1000), a representative Generation II LWR (Surry), and an SMR. On average, the AP1000, Surry, and SMR produces 139, 153, and 104 curies/ft3 (182, 200, and 136 terabecquerels/m3) 75 min after a Loss-of-coolant-accident (LOCA). Using Monte Carlo simulations, the SMR produces less radioactivity per volume in containment than the AP1000 and Surry 84% and 96% of the time, respectively. On average, the AP1000, Surry, and SMR produces 84, 106, and 7 thousand curies/ MW th (3.1, 3.9, and 2.5 petabecquerels/ MW th ) 75 min after a LOCA. The larger A/V ratio of the SMR plays a substantial role in reducing the radioactivity. While it is expected that the SMR would have a lower levels of radioactivity compared to the AP1000 and Surry, the SMR produces less radioactivity after normalizing by thermal reactor power and containment volume. With respect to environmental dose exposure, the US Environmental Protection Agency 1–5 rem (0.01–0.05 sieverts) Protective Action Guide (PAG) limits for whole body exposure is not exceeded at the 10-mile (16.1-km) EPZ using the mean estimates for the AP1000 and Surry. The iPWR does not exceed the 1 rem (0.01 sieverts) lower PAG limit for whole body exposure at the 5-mile (8-km) EPZ using the mean value. These findings can be used in conjunction with the improved analytical methods, found in the SOARCA study, to provide accurate and realistic estimates for exposure. This will help create a pathway to develop a regulatory basis for technology-neutral, risk-based approach to EPZs for iPWRs.

Battery energy storage systems (BESS) are increasingly deployed in microgrids due to their benefits in improving system reliability and reducing operational costs. Meanwhile, advanced small modular reactors (SMRs) offer many advantages, including relatively small physical footprints, reduced capital investment, and the ability to be sited in locations not possible for larger nuclear plants. In this paper, we propose a bi-level operational planning model that enables microgrid planners to determine the optimal BESS size and technology while taking into account the optimal long-term (a yearly simulation with a 15-min resolution) operations of a microgrid with SMRs and wind turbines. Case studies are performed using realistic BESS and grid data for two BESS technologies, i.e., Li-Ion battery and compressed air energy storage. Numerical results show the effectiveness of the proposed bi-level model. The pros and cons of the two BESS technologies are also revealed.

In an iPWR (integral pressurized water reactor), the pressurizer is located at the top of the reactor vessel; this configuration requires the investigation of the mechanisms adopted for the homogenization of boron. In previous work, three representative experiments were conducted in an experimental installation made of stainless steel with a volumetric scale equal to 1:200, representing one-fourth of the pressurizer of an iPWR. The test facility layout was mounted so that the test section was fed with water or saline solutions with different concentrations, representing scenarios of boration or deboration. To determine the concentration at the inlet and outlet of the test section, samples have been collected every 10 min during the experiments representing some scenarios. The main goal in this work was to investigate how well mixing during boron dilution transients in the pressurizer of a small modular reactor can be modelled accurately by CFD (Computational Fluid Dynamics) codes. Two CFD codes were used, the commercial ANSYS CFX and the open source CFD code OpenFOAM. The use of open source software such as OpenFOAM offers a way to CFD gain acceptance in the licensing. The results of the comparison of simulations with an experiment at the test section were presented and showed a very good agreement. It was verified that deviations are less than 4%, both codes can be used to accurately represent this phenomenon. In order to improve future experiments, the dispersion of the solution inside the test section is studied with the aim to propose positions for sensors. A first simple configuration is proposed, but some further simulations will be done to find an optimum configuration.

The growth in global energy demand, coupled with priorities to address a changing climate and sustainable development, has brought attention to the need for informed development of low-carbon energy sources in both developed and emerging economies. Fossil fuels are likely to continue playing a role in energy utilization, however low carbon sources—including nuclear and renewable energy sources—require critical consideration for adapting the global energy system in line with current pressures. The need for changes in energy provision is particularly important given that the production of electricity is the largest single source of greenhouse gas emissions on a global level, particularly in emerging economies. With low carbon energy priorities, nuclear energy has the potential to meet a critical share of related targets, presenting both challenges and opportunities for commercial adoption of nuclear power. An emerging share of future electricity and heat demand could be met by the deployment of small modular reactors (SMRs). Several characteristics of SMRs are expected to provide distinct advantages over large nuclear and potentially other baseload plants in certain markets. Such advantages stem from the reactors’ smaller size, simplicity of design, modularity, operational flexibility, incremental adoption, their ability to be deployed in areas where the infrastructure to support large power plants is insufficient, as well as the ability to integrate with renewable energy sources and provide a range of nonelectrical cogeneration and hybrid process applications, make SMRs to features make them a unique, low-carbon energy technology that may be deployed in a diverse set of locations and applications. This chapter couples the unique features of SMRs with demand, policy, and locational characteristics to evaluate deployment potential across a wide range of emerging market conditions.

This chapter provides an update on small modular reactor (SMR) deployment and research and development (R&D) in Russia, covering the experience in design and operation of the marine propulsion reactors, motivations for developing land-based and barge-mounted SMRs, design status, design and operating characteristics, safety features, and anticipated applications of such reactors. With Russia currently being the world leader in deployment of innovative SMRs, presented also are deployment and licensing status and progress toward deployment of the Russian SMRs, as well as main directions of their future development and the ongoing R&D. Provided are sources of further information, complete with a comprehensive list of the key references.

X-Energy is currently designing an innovative concept of nuclear power reactor: the Xe-100. It is a Small Modular Reactor (SMR) based in High Temperature Gas Cooled Reactor (HTGR) technology and it is currently under licensing process in the United States and Canada. In addition to the generic goals, the Xe-100 Human Factors Engineering (HFE) Program is conducted to provide evidence that a reduced staffing can safely operate several reactor modules from one control room. Advanced reactor designs are changing tasks, jobs, roles, responsibilities, size and composition of the operation crews relying on the increased use of automation technologies, passive safety features and adapted control stations designs. This paper explores the details and insights of analysis and validation activities of the HFE Program, providing the key-aspects to succeed in the Staffing Validation.

In the past decade, small modular reactor (SMR) technologies have advanced significantly with the first anticipated deployments in the 2020s. Canada has emerged to be a choice country for many SMR developers because of the readiness of Canada to regulate advanced SMRs, willingness by multiple jurisdictions to host SMR prototypes, existence of mature nuclear supply chain, experienced nuclear utilities, and extensive R&D capabilities to support advanced reactor technologies. This chapter provides a summary of activities and rapidly changing SMR landscape in Canada.

This chapter discusses the potential application of small modular reactor concepts in tightly coupled, nuclear hybrid energy system (NHES) architectures, also referred to as “integrated energy systems.” Such an implementation proposes to integrate multiple input resources to produce multiple output products, maximizing the use of both thermal and electrical energy during times of both low and high net electricity demand. Considerations in the design and optimization of NHES architectures capable of flexible operation and a path forward for the analysis and development of such systems are discussed.

Safety in nuclear power plants is an important area in the realm of engineering safety [1]. Small Modular Reactors (SMRs) are an emerging form of nuclear technology with widespread application, notably in austere or remote communities. SMRs are defined as power plants that produce 300 MWe or less [2], designed with modular fabrication technology for ease of onsite construction. Historically, nuclear power plants have maximized large economies of scale and been constructed with ample resources for safety regulation concerns, such as access to reliable water tables. SMRs will be deployed to remote locations without the resources normally afforded to a large power plant, and so the safety systems of these new designs must be innovative and still be able to meet the stringent safety specifications set forth by regulatory bodies [3]. This is a very important aspect of SMR design and is critical for licensing and production. This paper outlines a systematic literature review of scientific papers concerned with nuclear safety systems of SMRs. To further expound upon this topic, literature analyses were completed using keyword searches for, “nuclear safety systems,” and “small modular reactor” and then evaluating trends between articles. The databases used for this research were Google Scholar, Scopus, Web of Science, and Mendeley. The analyses were completed by use of the following literature review software: VOSViewer, Publish or Perish, MAXQDA and Vincinitas. The results are presented in the form of trend analyses, keyword cluster analysis, co-author clusters analysis, co-citation analysis, word clouds and emergence analyses. The results show a strong correlation between the study of this material and the rising interest in green energy, as well as the particular safety systems necessary for the development of SMRs.

The licensing and deployment of any small modular reactor (SMR) are dependent on whether (a) there is a significant market demand for new nuclear power, (b) SMR technology can be developed in a timely and cost-effective manner to meet the demand, and (c) the SMR technology can be licensed effectively. As described in this handbook, enhanced safety, improved security, and flexibility in siting and application are all factors that have created a market demand. Assuming a market demand for SMRs and an ability to finance, licensing becomes the next risk factor. Effective licensing is dependent, in part, on the maturity of the SMR technology. New and unproven nuclear technologies might present a challenge to effective licensing. Accordingly, near-term licensing and deployment of SMRs are focused on the proven light water reactor (LWR) technology. However as noted in Part Two, in recent years, non-LWR SMR advanced nuclear technologies have emerged, but none of these designs are sufficiently developed for licensing reviews. Some studies suggest that these non-LWR advanced designs should present an opportunity for a more performance-based, risk-informed licensing approach. The international nuclear energy community has established frameworks to identify and develop a more effective licensing approach and standards for these advanced SMR designs.

Response to the increasingly serious problems of global water risk in many arid regions of the planet has become a critical concern to governments. One of the best solutions to overcome the water shortage is using large-scale seawater desalination facilities. Currently, in many Western Asia countries with vast non-renewable resources, the fossil-fuel based power plants are considered as the dominant energy sources for driving the desalination plants (DPs). Considering numerous problems with fossil fuels, most of the water-scarce governments over the world are developing the long-term energy strategy of the country based on using sustainable and renewable energies. In this study, a techno-economic evaluation of hybrid DP powered by the Advanced Lead Fast Reactor European Demonstrator (ALFRED) and solar power plant (SPP), equipped with latent thermal storage system is conducted. The obtained results express that almost, 60% of required thermal energy for driving the thermal DP can be obtained by SPP.

Small modular reactor is seen as one of the most popular research directions in nuclear field, and lead-bismuth cooled fast reactors are widely chosen in the design of small modular reactors due to its excellent neutron properties and thermal conductivity. A 20MW lead-bismuth cooled fast reactor was designed in this paper and both fluent-based CFD analysis and cobra-based subchannel analysis were applied to its safety verification and design optimization. This paper not only presents a verified design of small modular Lead-bismuth cooled fast reactor with thorough thermal-hydraulics analysis, but also presents a platform to design heavy metal cooled fast reactor.

To achieve sustainable solutions to the current problems in energy, it is required to analyze sustainable development factors, environmental conditions, long-term plans, and actions that are considered as crucial. Energy is currently prevalent, and nuclear power resembles to provide one aspect of an efficient and sustainable solution. In this paper, Hybridized Heuristic Heterogeneous Mathematical Model (HHHMM) has been proposed for the sustainable International comparison of the economic efficiency of Nuclear energy. The proposed mathematical model is derived that nuclear energy is economically feasible to produce a progressive share of future electricity supply to achieve increasing electricity in the economy. Furthermore, the assessment is performed for a Nuclear energy integration system included a Small Modular Reactor (SMR) where a portion of the heat produces is used for the production of hydrogen via high-temperature steam electrolysis (HTSE).In addition, the economic risk is calculated by excessive energy costs and varying energy consumption, economic reactor indices and CO2 emissions constraints. Finally, the Economic loss probability distribution functions, feasibility and Sustainable Efficiency Factor (SEF) for nuclear energy strategies has been analyzed in the experimental results. Based on the analysis, there is a long-term relationship among the parameters and the effect on energy efficiency from energy sources is positive and energy from renewable sources is more advantageous in terms of energy efficiency with nuclear energy.