The Supercritical CO2 Heat Removal System (sCO2-Hero)
– Short description: The “supercritical CO2 heat removal system”, sCO2-HeRo, safely, reliably and efficiently removes residual heat from nuclear fuel without the requirement of external power sources. This system therefore can be considered as an excellent backup cooling system for the reactor core or the spent fuel storage in the case of a station blackout and loss of ultimate heat sink. sCO2-HeRo is a very innovative reactor safety concept as it improves the safety of both currently operating and future BWRs and PWRs through a self-propellant, self-sustaining and self-launching, highly compact cooling system powered by an integrated Brayton-cycle using supercritical carbon dioxide. Since this system is powered by the decay heat itself, it provides new ways to deal with accidents that are beyond design.
The sCO2-HeRo provides breakthrough options with scientific and practical maturity, which will be proven by means of numerical tools, like advanced CFD, and small-scale experiments to determine the performance of the components like a compact heat exchanger and a turbo-machine set. A demonstration unit of the sCO2-HeRo system will be installed in a unique glass model in order to demonstrate the maturity of the system. Finally, the potential of this system to deal with a range of different accident scenarios and beyond-design accidents will be shown with the help of the German nuclear code ATHLET.
– Project website: http://www.sco2-hero.eu
– Link to CORDIS: https://cordis.europa.eu/project/rcn/196912/factsheet/en
Supercritical CO2 Cycle for Flexible & Sustainable Support to the Electricity System (sCO2-Flex)
–Short description: Current fossil-fuel power plants have been designed to operate in base-load conditions, i.e to provide a constant power output. However, their role is changing, due to the growing share of renewables, both in and outside the EU. Fossil-fuel plants will increasingly be expected to provide fluctuating back-up power, to foster the integration of intermittent renewable energy sources and to provide stability to the grid. However, these plants are not fit to undergo power output fluctuations.
In this context, sCO2-Flex consortium addressees this challenge by developing and validating (at simulation level the global cycle and at relevant environment boiler, heat exchanger(HX) and turbomachinery) the scalable/modular design of a 25MWe Brayton cycle using supercritical CO2, able to increase the operational flexibility and the efficiency of existing and future coal and lignite power plants.
sCO2-Flex will develop and optimize the design of a 25MWe sCO2 Brayton cycle and of its main components (boiler, HX, turbomachinery, instrumentation and control strategies) able to meet long-term flexibility requirements, enabling entire load range optimization with fast load changes, fast start-ups and shut-downs, while reducing environmental impacts and focusing on cost-effectiveness. The project, bringing the sCO2cycle to TRL6, will pave the way to future demonstration projects (from 2020) and to commercialization of the technology (from 2025). Ambitious exploitation and dissemination activities will be set up to ensure proper market uptake.
– Project website: https://www.sco2-flex.eu
– Link to CORDIS: https://cordis.europa.eu/project/rcn/211750/factsheet/en
UNITED STATES OF AMERICA
– Short description: NET Power has developed a novel power system that produces electricity from natural gas. The technology is cost competitive with current technologies but generate zero atmospheric emissions – eliminating the smokestack altogether. This system is based on a new thermodynamic cycle called the Allam Cycle which is a breakthrough in power generation technology. It uses a high-pressure, highly recuperative, oxyfuel, supercritical CO2 cycle that makes emission capture a part of the core power generation process, rather than an afterthought. The result is high-efficiency power generation that inherently produces a pipeline-quality CO2 byproduct at no additional cost to the system’s performance.
– Company’s website: https://www.netpower.com/
– More info: Power Magazine, Pioneering Zero-Emission Natural Gas Power Cycle Achieves First-Fire, May 2018. Link
Supercritical Transformational Electric Power (STEP)
– Short description: The United States Department of Energy (DOE) Supercritical Transformational Electric Power (STEP) program has awarded USD 80 million towards a public-private program to demonstrate a fully integrated functional 10 megawatts electrical (MWe) power plant that uses sCO2 instead of steam as the working fluid to run a turbine in a Brayton cycle. The thermodynamic advantages allow the power plant to generate the same amount of electricity from less fuel with smaller equipment, which decreases CO2 emissions and operating costs. This initiative will integrate and prove compact, modular technologies that can be used across a broad array of applications, efficiently converting heat to electric power and creating clean energy from natural gas, coal, next-generation nuclear, concentrated solar thermal, and industrial waste heat sources.
The Gas Technology Institute (GTI), Southwest Research Institute (SwRI), and General Electric (GE) are leading the team working to revolutionize future power generation. The transformational supercritical carbon dioxide (sCO2) power cycle technology being designed and constructed in San Antonio, Texas will be cleaner, more compact, and more energy efficient than current electricity generation.
– Project website: https://www.netl.doe.gov/node/7549
More information about Supercritical CO2 programmes in USA can be found in the website of the Department of Energy’s National Energy Technology Laboratory
In addition to the projects listed above, the contribution of other smaller facilities to the development of sCO2 technology must also be acknowledged. Most of these facilities, at the micro (<500 kWe) or mini scale (<1MWe), are located in USA (SANDIA National Laboratories, BechtelMarine Propulsion Corporation) but there are also other systems in operation in Asia (KAERI and KAIST in South Korea, Tokyo Institute of Technology in Japan and the Nuclear Power Institute of China), Europe (Research Centre Rez in Prague, Czech Republic) and Australia (University of Queensland). Finally, a note on the single commercially available system in the market must be made; this is an 8 MWe unit for Waste Heat Recovery developed by Echogen and currently commercialized by Siemens through Dresser-Rand.