Modeling of Stress Distribution in Molten Salt Thermal Energy Storage Tanks for In-Service Central Receiver Power Plants

Julian Osorio, Mark Mehos, Janna Martinek, Bill Hamilton, Luca Imponenti, Bruce Kelly, Hank Price, Zhenzhen Yu, Chen Ni, Alejandro Rivera-Alvarez, Jose Torres, Cesar Nieto

Research output: NRELPresentation


Failures in molten nitrate salts thermal energy storage tanks (TES) have been occurring in several concentrating solar power (CSP) plants around the world after a few months or years of operation. These failures are mainly related to a combination of high stress, corrosion, large deformation, and thermal cycling. Most of these failures are a consequence of the infancy of this technology; technical standards for design, fabrication, implementation, and operation of molten salt tanks operating at temperatures up to 565 degrees Celsius do not exist and most of current in-service tanks have been designed using the recommendations from the American Petroleum Institute (API) 650 and the American Society of Mechanical Engineers ASME section II standards, which are applicable for TES tanks operating at lower temperatures. We have developed a 3-dimensional model of a representative molten salt hot tank design that uses typical CSP plant operation conditions and allows determining the temperature and stress distribution in the tank. The model also considers the initial floor residual stresses and distortion after its welding fabrication. We have identified critical thermal gradients in the tank floor and shell and locations in the tank where the stresses are high and could become susceptible points for failure.
Original languageAmerican English
Number of pages23
StatePublished - 2023

Publication series

NamePresented at the 5th Thermal-Mechanical-Chemical Energy Storage Workshop, 2-3 August 2023, San Antonio, Texas

NREL Publication Number

  • NREL/PR-5700-87158


  • concentrating solar power
  • floor fabrication
  • molten salt thermal energy storage
  • residual stress
  • tank failure
  • transient operation


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