As the demand for fl exible, low-carbon energy solutions grows, this project explores the design of a fast-ramping sodium-cooled fast reactor (SFR) to support modern electrical grids challenged by variable renewable energy sources. The selected 2000 MWt reactor uses control rods for reactivity control, with europium oxide (Eu₂O₃) optimized as the absorber material. Simulations in OpenMC, paired with point kinetics analysis, confi rmed the reactor’s ability to ramp from 10% to 100% power at 10% per minute. Thermal safety and structural integrity were verifi ed under transient conditions, and the design meets the targeted capital cost of $1000/kWe offering a safe, responsive, and cost-effective nuclear alternative to traditional peaker plants.
Team: Owen Carmicino, Jay Gaiardelli, Mills Haskett, Anna Tam
Project Advisor: Prof. Yaron Danon, Peter Brain, Nick Thompson
Members of the design group
Project Motivation
The growing integration of solar energy into the electrical grid has introduced new challenges in balancing supply and demand due to its intermittent nature. Addressing these fl uctuations requires energy technologies capable of rapid ramping, since current energy storage solutions, such as batteries, remain signifi cantly more expensive than grid electricity. While natural gas plants currently fi ll this role, fast-ramping nuclear reactors present a promising alternative, offering the benefi ts of low-carbon emissions and cost-effective, energy-dense fuel.
Figure 1: Radial Layout of Reactor Core
Project Description
This project aims to develop a fast-ramping nuclear reactor design that meets key performance and economic criteria specified by the customer. The reactor must be capable of ramping power output at a rate of 10% per minute, with the ability to operate flexibly across a wide power range—from 10% to 100% of full capacity. To ensure economic viability, the design will target overnight capital costs at or below $1000 per kilowatt-electric (kWe). Additionally, the reactor
must maintain safety and structural integrity during rapid transients, ensuring reliable operation under dynamic grid conditions.
Figure 2: Control Rod Insertion Profile and Required Reactivity for Achieving 10% to 100% Power Ramping
Results and Accomplishments
The sodium-cooled fast reactor (SFR) was selected as the most suitable design to meet the project’s performance, safety, and economic objectives. This choice was driven by the advantages of operating in the fast neutron spectrum, where issues like fission product poisoning are significantly reduced compared to traditional pressurized water reactors (PWRs). A 2000 MWt reactor core was developed and modeled using the Monte Carlo simulation tool OpenMC, with the radial core layout shown in Figure 1. Control rods serve as the primary mechanism for both reactivity control and power ramping.
Europium oxide (Eu₂O₃) was chosen as the absorber material for the control rods due to its favorable neutron absorption properties and low cost. The control rod worth was calculated using OpenMC simulations, and, in combination with point kinetics equations, the required reactivity insertions for meeting ramping demands were determined.
The final reactor design demonstrated the capability to ramp power output from 10% to 100% at a rate of 10% per minute, satisfying the customer’s performance requirements, as shown in Figure 2. Thermal analysis confirmed that the fuel centerline temperature and cladding remained within safe operating limits throughout transient conditions, ensuring structural integrity and safe operation during power changes.
Additionally, a cost evaluation confirmed that the reactor approaches the targeted overnight capital cost of $1000/kWe, reinforcing its potential as a cost-effective and flexible power generation solution. Overall, the project successfully delivered a technically sound and economically viable fast reactor concept capable of supporting modern, dynamic electrical grids.