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Title: Integrated Cyber/Physical Impact Analysis to secure US Critical Infrastructure

Technical Report ·
DOI:https://doi.org/10.2172/1761819· OSTI ID:1761819

In a common electric power plant, heat is used to boil water into steam which drives a turbine. The steam from the turbine outlet is condensed with cooling water. This is the common Rankine cycle and, even after decades of development is relatively inefficient and water intensive. Alternatively, a closed Brayton cycle recirculates the working fluid, and the turbine exhaust is used in a recuperating heat exchanger to heat the turbine feed. A "supercritical cycle' is a closed Brayton cycle in which the working fluid, such as supercritical carbon dioxide (sCO2), is maintained above the critical point during the compression phase of the cycle. The key property of the fluid near its critical point is its higher gas density, closer to that of a liquid than of a gas, allowing for the pumping power in the compressor to be significantly reduced resulting in improved efficiency. Other advantages include smaller component size and the reduced use of water, not only due to the increased efficiency, but also due sensible heat rejection which facilitates dry air cooling compared to air-cooled steam condensers. A Sandia National Laboratories commercialization review concluded that the technology has applicability across various power generation applications including fossil fuels, concentrated solar power and nuclear power. In 2006, Sandia National Laboratories (SNL), recognizing the potential advantages of a higher efficiency power cycle, used internal funds to establish a testing capability and began partnering with the U.S. Department of Energy Office of Nuclear Energy to develop a laboratory-scale test assembly to show the viability of the underlying science and demonstrate system performance. Since that time, SNL has generated power, verified cycle performance, and developed cycle controls and maintenance procedures. The test assembly has successfully operated in different configurations (simple Brayton, waste heat cycle, and recompression) and tested additives to the s-CO2 working fluid. Our current focus is to partner with industry and develop cycle components and control strategies sufficient to support a successful commercial offering. This paper has been developed for the Energy Policy Institute's (EPI's) 6th Annual Energy Policy Research Conference scheduled for 8 & 9 September 2016 in Santa Fe, NM. We describe the cycle in more detail and describe specific benefits and applications. The paper will also include current technology development activities and future plans.

Research Organization:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA)
DOE Contract Number:
AC04-94AL85000
OSTI ID:
1761819
Report Number(s):
SAND-2016-8203; 671240
Country of Publication:
United States
Language:
English