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Title: Castable Cement Can Prevent Molten-Salt Corrosion in CSP

Abstract

NREL's study demonstrated that castable cements on metals are a protective barrier that can prevent permeation of molten salts toward metallic surfaces. The silica-based castable cement Aremco 645-N, when sprayed with boron nitride, can protect containment metallic alloys from attack by molten chlorides at high temperatures (650 degrees C) in short-term tests. Improved thermal energy storage technology could increase the performance of CSP and reduce costs, helping to reach the goal of the U.S. Department of Energy's SunShot Initiative to make solar cost-competitive with other non-renewable sources of electricity by 2020.

Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy Communications and Outreach
OSTI Identifier:
1324954
Report Number(s):
NREL/FS-5500-67037
DOE Contract Number:
AC36-08GO28308
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; castable cement; concentrating solar power; CSP; molten salts

Citation Formats

. Castable Cement Can Prevent Molten-Salt Corrosion in CSP. United States: N. p., 2016. Web.
. Castable Cement Can Prevent Molten-Salt Corrosion in CSP. United States.
. 2016. "Castable Cement Can Prevent Molten-Salt Corrosion in CSP". United States. doi:. https://www.osti.gov/servlets/purl/1324954.
@article{osti_1324954,
title = {Castable Cement Can Prevent Molten-Salt Corrosion in CSP},
author = {},
abstractNote = {NREL's study demonstrated that castable cements on metals are a protective barrier that can prevent permeation of molten salts toward metallic surfaces. The silica-based castable cement Aremco 645-N, when sprayed with boron nitride, can protect containment metallic alloys from attack by molten chlorides at high temperatures (650 degrees C) in short-term tests. Improved thermal energy storage technology could increase the performance of CSP and reduce costs, helping to reach the goal of the U.S. Department of Energy's SunShot Initiative to make solar cost-competitive with other non-renewable sources of electricity by 2020.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2016,
month = 9
}
  • Castable cements on metals form a protective barrier that is able to prevent permeation of molten salts towards metallic surfaces. Silica-based castable cements are capable of protecting containment metallic alloys from the corrosive attack of molten chlorides at temperatures as high as 650 °C. Boron nitride (BN) blocking the pores in the cured cement prevents permeation of the molten chloride towards the metal surface. The cements tested are not chemically stable in molten carbonates, because the bonding components dissolved into molten carbonates salt. The corrosion rate is 7.72±0.32 mm/year for bare stainless steel 347 in molten eutectic NaCl – 65.58more » wt% LiCl at 650 °C, which is the baseline used for determining how well the cement protects the metallic surfaces from corrosion. In particular the metal fully encapsulated with Aremco 645-N with pores filled with boron nitride immersed in molten eutectic NaCl – 65.58 wt% LiCl at 650 °C shows a corrosion rate of 9E-04 mm/year. Here, the present study gives initial corrosion rates. Long-term tests are required to determine if Aremco 645-N with BN coating on metal has long term chemical stability for blocking salt permeation through coating pores.« less
  • There is a strong resurgent interest worldwide in heavy-liquid metals as nuclear coolant and spallation neutron target material. The continuing research and development (R and D) in accelerator-driven systems and accelerator-driven transmutation of waste have brought attention to the lead-bismuth eutectic (LBE) nuclear coolant technology. Around the world R and D organizations are investigating the LBE technology in the areas of materials and corrosion, coolant quality control, thermal hydraulics, and nuclear data. There have also been concerted efforts to develop very long lived core, lead-alloy-cooled, proliferation-resistant, super safe, and transportable reactors. In this paper, the thermodynamic basis for controlling oxygenmore » level in lead-bismuth to prevent steel corrosion and coolant contamination is examined. The operational conditions, including the thermodynamic activity of oxygen, cover-gas oxygen partial pressure, mixtures of H{sub 2} and H{sub 2}O (steam) for obtaining such low oxygen partial pressure, and the voltage signals of one type of oxygen sensors (with solid electrolyte and molten bismuth electrode) are calculated. These results provide the guidance to implement the oxygen control technique. The authors are performing laboratory experiments to verify this understanding and building an LBE material and thermal-hydraulic test facility to further develop LBE technology for accelerator transmutation of wastes applications.« less
  • Corrosion and slow crack growth of hot-pressed Si{sub 3}N{sub 4}- based ceramic materials were studied to arrive at an initial determination of the severity of Na{sub 2}SO{sub 4} molten salt environments. Slow crack growth testing revealed that Na{sub 2}SO{sub 4} molten salt exposure accelerated crack growth in hot-pressed Si{sub 3}N{sub 4} compared to crack growth in air at 1300 C. The salt exposure was observed to reduce the time to failure of precracked specimens by factors of two or three. Measured crack velocity was observed to obey a power law, V = AK{sup n}, with n = 5.2 {plus minus}more » 0.2 and A = 7.6 {times} 10{sup {minus}10}. Standard corrosion coupon tests were performed on specimens of Si{sub 3}N{sub 4}/SiC-reinforced composites and hot-pressed Si{sub 3}N{sub 4} monolithic material. Weight change measurements were performed after eight-hour immersion exposures at 950, 975, and 1000 C to Na{sub 2}SO{sub 4}. Hot-pressed Si{sub 3}N{sub 4} + 5% MgO and Si{sub 3}N{sub 4}/SiC whisker-reinforced material exhibited similar surface features after molten salt exposure. A Si{sub 3}N{sub 4}/SiC fiber-reinforced material, however, revealed complete dissolution of SiC chopped fiber reinforcements.« less
  • Considerable amount of work is going on regarding the development of high temperature liquid salts technology to meet future process needs of Next Generation Nuclear Plant. This report identifies the important characteristics and concerns of high temperature molten salts (with lesson learned at University of Wisconsin-Madison, Molten Salt Program) and provides some possible recommendation for future work