Wastage and Self-Plugging by a Potential CO2 Ingress in a Supercritical CO2 Power Conversion System of an SFR

Abstract

For a CO 2 ingress accident into liquid sodium in a supercritical CO 2 power conversion system coupled with a sodium-cooled fast reactor, we investigated two major design issues: i) a wastage phenomenon in regard to structural damage adjacent to the leaking position, and ii) potential channel plugging due to the formation of a particulate reaction product. In order to understand the factors affecting the occurrence of these issues, two kinds of experiments were carried out: a wastage effect test and a self-plugging test. All experimental conditions were chosen to reasonably represent the normal operating conditions and realistic design parameters of the reference plant. The test results indicate the absence of wastage, which will not lead to additional tube ruptures and damage propagation. In the current experiment, the self-plugging of PCHE channels only took place under two limited conditions: i) the sodium temperature is over 500 C and ii) the equivalent diameter of the crack opening is less than 1.5 mm with a small leakage rate of far less than 1 g/s of CO 2 ingress.

Effect of pressure on the corrosion and carburization behavior of chromia-forming heat-resistant alloys in high-temperature carbon dioxide environments

“…The advantages of the S-CO 2 Brayton cycle include an increase in thermal efficiency, a reduction of CO 2 emission, and a compact size of components compared with the conventional steam Rankine cycle and Brayton cycles at an operating temperature above 500 • C [1,2]. In addition, an indirect S-CO 2 cycle coupled to the sodium-cooled fast reactor (SFR) could eliminate the possibility of an explosive reaction between hightemperature steam and liquid sodium [4,5], thus enhancing the safety of the nuclear systems. On the other hand, for the selection of candidate structural materials in a high-temperature S-CO 2 environment, it is essential to assess the material compatibility because excessive corrosion, oxide spallation, and internal carburization might deteriorate the heat transfer capability and long-term integrity of components, such as the compact-type intermediate heat exchanger (IHX).…”

“…The supercritical-carbon dioxide (S-CO 2 ) Brayton cycle is an attractive option for energy conversion systems of next-generation nuclear reactors, advanced-fossil power plants, and other power generating applications [1][2][3][4][5]. The advantages of the S-CO 2 Brayton cycle include an increase in thermal efficiency, a reduction of CO 2 emission, and a compact size of components compared with the conventional steam Rankine cycle and Brayton cycles at an operating temperature above 500 • C [1,2].…”

Description of the First Observed Sodium-C0₂ Reactions in the Sodium CO₂ Interaction Experiment (SNAKE)

“…Approximately 325 standard liters of CO 2 were injected into a 45 cm (15 inch) high column of sodium at a nominal temperature of 150 ˚C over the course of 3 hours. The inlet CO 2 No plugging of the micro-nozzle was detected during this experiment. Data from these experiments was reported and initial analyses of the data were completed and discussed.…”

Report on the Initial Fundamental Sodium-CO₂ Interaction Experiment

“…It should also be noted that the production of carbon monoxide at the test temperature completed here (170 ˚C) is not necessarily expected. Other researchers (Eoh et al, 2010) have not seen substantial reaction products until a temperature of 300 ˚C. This is an additional reason for skepticism that CO was generated during this first test.…”