Facebook Instagram Youtube Twitter

Heatup and Cooldown Rate Limits

The NSSS heat up from Cold Shutdown (MODE 5) to Hot Standby (MODE 3) is performed by reactor coolant pumps which are very powerful (they can consume up to 6 MW each), and therefore its work together with a decay heat can be used for heating the primary coolant before a reactor startup. Reactor coolant system pressure must be increased to satisfy net positive suction head requirements to operate the reactor coolant pumps. Reactor coolant pumps are started sequentially. The primary plant heat-up rate is limited to about 30°C per hour to minimize internal stress in the material of the pressure vessel, primary piping, and other components.

Heat up, and cooldown rate limits are based upon the impact on the future fatigue life of the plant. The heat up and cooldown limits ensure that the plant’s fatigue life is equal to or greater than the plant’s operational life. Large components such as flanges, the reactor vessel head, and even the reactor vessel itself are the limiting components. Usually, the most limiting component will set the heat up and cool down rates.


Materials Science:

  1. U.S. Department of Energy, Material Science. DOE Fundamentals Handbook, Volume 1 and 2. January 1993.
  2. U.S. Department of Energy, Material Science. DOE Fundamentals Handbook, Volume 2 and 2. January 1993.
  3. William D. Callister, David G. Rethwisch. Materials Science and Engineering: An Introduction 9th Edition, Wiley; 9 edition (December 4, 2013), ISBN-13: 978-1118324578.
  4. Eberhart, Mark (2003). Why Things Break: Understanding the World, by the Way, It Comes Apart. Harmony. ISBN 978-1-4000-4760-4.
  5. Gaskell, David R. (1995). Introduction to the Thermodynamics of Materials (4th ed.). Taylor and Francis Publishing. ISBN 978-1-56032-992-3.
  6. González-Viñas, W. & Mancini, H.L. (2004). An Introduction to Materials Science. Princeton University Press. ISBN 978-0-691-07097-1.
  7. Ashby, Michael; Hugh Shercliff; David Cebon (2007). Materials: engineering, science, processing, and design (1st ed.). Butterworth-Heinemann. ISBN 978-0-7506-8391-3.
  8. J. R. Lamarsh, A. J. Baratta, Introduction to Nuclear Engineering, 3d ed., Prentice-Hall, 2001, ISBN: 0-201-82498-1.

See above:
Power Plant Materials