Conference Agenda

In the era of carbon neutrality, low-carbon hydrogen production technology is emerging as a source of hydrogen energy that can replace fossil fuels. As one of the low-carbon hydrogen production technologies, the High Temperature Steam Electrolysis (HTSE) methods that produce hydrogen through electrolysis of high-temperature steam are gaining attention. In this regard, the Korea Atomic Energy Research Institute (KAERI) has conducted an integral test for hydrogen production by coupling a helium loop simulating a high-temperature gas-cooled reactor with a high-temperature steam/air supply system and an HTSE system including two Solid Oxide Electrolyte Cells (SOEC) for hydrogen production. The heat provided by the helium loop is utilized to produce steam and air suitable for HTSE through a steam generator and multi-stream heat exchanger in a high-temperature steam/air production system. These are provided to the SOEC stacks within the HTSE system to produce hydrogen. The integral test results confirmed that the helium loop and the high-temperature steam/air supply system could be coupled to reliably supply the steam and air with suitable temperature, pressure, and flow conditions for the SOEC stacks. In addition, the results demonstrated that two 3kw SOEC stacks at 700℃ with 80A of current produced 4.3kg/day of hydrogen.

Using a Light Water Reactor (LWR) to produce steam for process heating is a topic of rising interest in the industry. LWR process steam has been successfully used in district heating and in petrochemical processes operating at lower pressures and temperatures. However, to make a significant impact on decarbonizing petrochemical plants, higher pressures and temperatures would be advantageous. Previous studies have suggested that high temperature gas reactors would be best suited for this application. However, a recent study by the Idaho National Laboratory, comparing a NuScale plant with augmented steam compression and heating, to a high temperature gas reactor, has shown that both options are technical viable and economically competitive.

This paper examines the use of a steam production cycle in which steam generated by a single NuScale Power Module (NPM) is directed through an intermediate heat exchanger to produce process steam that is subsequently compressed and heated to achieve commercial scale steam temperatures, pressures, and flow rates. For example, a six module NuScale plant fully dedicated to steam production can produce 1088 metric tons of steam per hour (2.4 Mlb/hr) at 500^oC and 6.8 MPa using commercially available compressors and heaters. The NuScale flexible modular design makes it possible to assign one or more NPMs to produce steam and other NPMs to produce electricity, or each NPM can produce steam and electricity simultaneously. Process controls and regulatory requirements are also evaluated.

The Inertial Electrostatic Confinement Thruster (IECT) presents a promising solution as a space electric thruster device that employs an external centripetal electrostatic field to generate thrust through plasma interaction. This paper proposes a nuclear-powered IECT space propulsion system by using the system simulation language Modelica. To improve the accuracy and efficiency of system simulation across different spatiotemporal scales, this paper introduces a synchronous time Modelica-C coupled simulation method that accelerates calculations related to the IECT core. Furthermore, a multi-dimensional particle-in-cell simulation is implemented to better represent the physical processes occurring within the IECT core. System-level simulations are conducted to analyze the performance of the proposed system under various working conditions. The simulation results demonstrate that the proposed system can achieve satisfactory performance with significantly reduced resource requirements. Notably, Modelica exhibits robust capabilities for modeling space nuclear power systems and accurately describes plasma systems when coupled with external C code.

Integrated energy systems (IES) represent an emerging innovation for decarbonizing the power and industrial sectors. In response to this transition, decision-makers must address site-specific capacity and operation planning for heat and power supply, as well as the extent of heat and market engagement. The literature on the IES widely evaluates its economic viability under energy arbitrage operations. These operations leverage price differentials by reallocating energy production across spatial or temporal dimensions. However, prior studies have not examined various conflicting goals that decision-makers encounter in investment. For instance, industrial plant owners may aim to maximize nuclear heat utilization in their production processes to meet carbon emission targets, potentially replacing their existing fossil fuel energy sources. On the other hand, some may have limited grid access capacities for selling and buying electricity, which constrains arbitrage operations. Thus, we aim to make the following contributions in this work: (1) we introduce four reactor deployment scenarios to examine varying reactor capacity planning, considering decision-makers to either partially or completely replace their existing energy facilities with nuclear energy, (2) we formulate different grid access availabilities to identify optimal thermal energy storage (TES) and balance-of-plant capacities under site-specific constraints, (3) we assign additional operational targets, including maximizing electricity sales, minimizing carbon emissions, and minimizing dependency on external grids. The Xe-100 reactor and two-tank molten salt TES designs are optimized for various real-world industrial load scenarios. Our results reveal significant variations in system sizing and operation, highlighting the importance of including tailored constraints and operational goals.

Thermal energy storage is a promising technology that enables greater efficiency, load following, and therefore enhanced economy of nuclear reactors. The metrics to evaluate latent heat storage units are often material focused, which accounts for properties such as conductivity, latent heat, and density but fails to represent system level characteristics. We instead introduce a realistic metric that captures a more comprehensive system level thermal performance. To this end we seeked to use rate capability curves and a Ragone plot in the context of high-temperature latent heat storage. The Ragone plot helped elucidate design effectiveness and material pairings that would best balance energy storage and power delivery.

In this study, we designed a latent heat thermal storage system to pair Kairos Power’s KP-FHR with an energy storage amount equal to 10 hours of full power. Specifically, we investigated the impacts of thermal storage geometries and heat exchanger configurations on the system capacity and scale. Our preliminary design of the latent heat storage system has achieved a 7 times volume reduction compared to an equated two-tank sensible heat storage. We also carried out CFD simulation in Star-CCM+ to study the transient characteristics of these candidate geometries. Using these simulation results, we have demonstrated the use of rate capability curves and a Ragone plot to evaluate the comprehensive system performance.