Sodium Compatibility of Advanced Materials

Technical Report · Tue Sep 15 04:00:00 EDT 2009

DOI:https://doi.org/10.2172/2505021· OSTI ID:2505021

Natesan, Krishnamurti ^[1]; Li, Meimei ^[1]; Momozaki, Yoichi ^[1]; Rink, David L. ^[1]

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1. Argonne National Laboratory (ANL), Argonne, IL (United States)

This report gives a description of ongoing activities in the design, fabrication, construction, and planned testing of advanced structural materials in a forced convection sodium flow loop. The work is the Argonne National Laboratory (ANL) portion of the effort on the work project entitled, "Sodium Compatibility of Advanced Fast Reactor Materials," with Oak Ridge National Laboratory (ORNL) as the technical lead and is a part of Advanced Structural Materials Program for the Advanced Fuel Cycle Initiative (AFCI) Reactor Campaign. The objective of this project is to develop information on sodium corrosion compatibility of advanced materials being considered for sodium reactor applications. This report is the third deliverable from ANL in FY09 (M3505050704) under the work package “Sodium Compatibility of Advanced Fast Reactor Materials.” An earlier report examined the thermodynamic and kinetic factors involved in the purity of liquid sodium coolant for sodium reactor applications. Available information was presented on solubility of several metallic and nonmetallic elements along with a discussion of the possible mechanisms for the accumulation of impurities in sodium. That report concluded that the solubility of many metals in sodium is low (<1 part per million) in the temperature range of interest in sodium reactors and such trace amounts would not impact the mechanical integrity of structural materials and components. The earlier report also analyzed the solubility and transport mechanisms of nonmetallic elements such as oxygen, nitrogen, carbon, and hydrogen in laboratory sodium loops and in reactor systems such as Experimental Breeder Reactor-II (EBR-II), Fast Flux Test Facility (FFTF), and Clinch River Breeder Reactor (CRBR). Among the nonmetallic elements discussed, oxygen is deemed controllable and its concentration in sodium can be maintained in sodium for long reactor life by using cold-trap method. It was concluded that among the cold-trap and getter-trap methods, the use of cold trap is sufficient to achieve oxygen concentration of the order of 1 part per million. Under these oxygen conditions in sodium, the corrosion performance of structural materials such as austenitic stainless steels and ferritic steels will be acceptable at a maximum core outlet sodium temperature of ≈550°C. In the current sodium compatibility studies, the oxygen concentration in sodium will be controlled and maintained at ≈1 ppm by controlling the cold trap temperature. Among the nonmetallic elements in sodium, carbon was assessed to have the most influence on structural materials since carbon, as an impurity, is not amenable to control and maintenance by any of the simple purification methods. The dynamic equilibrium value for carbon in sodium systems is dependent on several factors, details of which were discussed in the earlier report. Furthermore, the transport of carbon in the primary and secondary loops of the reactor system and its effect on the carburization-decarburization behavior of structural components was addressed. Based on this assessment, the current sodium compatibility studies will examine the role of carbon concentration in sodium on the carburization-decarburization of advanced structural materials at temperatures up to 650°C. Carbon will be added to the sodium by exposure of carbon-filled iron tubes, which over time will enable carbon to diffuse through iron and dissolve into sodium. The method enables addition of dissolved carbon (without carbon particulates) in sodium that is of interest for materials compatibility evaluation. The removal of carbon from the sodium will be accomplished by exposing carbon-gettering alloys such as refractory metals that have a high partitioning coefficient for carbon and also precipitate carbides, thereby decreasing the carbon concentration in sodium.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE)
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 2505021
• Report Number(s): ANL-AFCI--276; 65204
• Country of Publication: United States
• Language: English

Related Subjects

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22 GENERAL STUDIES OF NUCLEAR REACTORS
36 MATERIALS SCIENCE