Compatibility of Lead-Bismuth Eutectic with SiC-Coated Graphite at Elevated Temperature
- PDF / 1,189,231 Bytes
- 5 Pages / 593.972 x 792 pts Page_size
- 51 Downloads / 142 Views
to meet the growing energy demands and to counter the negative atmospheric effects arising due to usage of fossil fuels, hydrogen has emerged as a clean, reliable, and sustainable energy source.[1] In this regard, Bhabha Atomic Research Centre (BARC) is engaged in developing a prototype Compact High Temperature Reactor (CHTR), which aims at the production of industrially usable hydrogen by splitting of water.[1,2] The CHTR uses U-233- and thorium-based carbide as fuel (TRISO-coated particle) compacted in a graphite matrix.[3] Cylindrical fuel compacts are packed in fuel bores located at the walls of each graphite fuel tube. The arrangement of the fuel tube placed along with the BeO moderator is shown in Figure 1. The core heat is removed by natural circulation of lead-bismuth eutectic alloy [44.5 wt pct Pb + 55.5 wt pct Bi], which enters the fuel tube at 1173 K (900 °C) at the lower plenum, takes POULAMI CHAKRABORTY, Scientific Officer-E, is with the Fusion Reactor Materials Section, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, Maharashtra, India. Contact emails: [email protected]; [email protected]. ABHIJIT GHOSH, Scientific Officer-G, is with the Glass and Advanced Materials Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, Maharashtra, India. GAUTAM KUMAR DEY, Distinguished Scientist, is with the Materials Science Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, Maharashtra, India. Manuscript submitted April 11, 2016. Article published online August 29, 2016. METALLURGICAL AND MATERIALS TRANSACTIONS B
the reactor heat, and leaves the tube at 1273 K (1000 °C) from the upper plenum. Thus, maintenance of long-term integrity of the graphite fuel tube in the presence of lead-bismuth eutectic (LBE) in the temperature range of 1173 K to 1273 K (900 °C to 1000 °C) is an important factor in deciding the feasibility of this process. LBE is found to be substantially corrosive toward various structural materials like austenitic stainless steels.[4,5] Moreover, experiments to study the compatibility of graphite with LBE at 1073 K (800 °C) have revealed the formation of a lead-carbon reaction layer over the graphite surface that had an estimated growth rate of 61.3 lm/year.[6,7] Considering this aspect, a protective oxidation- and corrosion-resistant coating of silicon carbide (SiC) has been proposed over the graphite fuel tubes. Nevertheless, obtaining a uniform and adherent SiC coating over graphite material is a major challenge. Although SiC is a relatively hard and inert material, compatibility of the same with LBE at the high working temperatures of CHTR remains another important area of investigation.[8,9] With this view, a layer of SiC was formed on a graphite pellet through the slurry-based silicon coating followed by in situ reaction at an elevated temperature. Later, the corrosion behavior of the coated pellet with molten LBE was studied in static condition for 200 hours at 1173 K (900 °C). Commercially available graphite pellets of 17 mm diameter (5 mm thickness) were coate
Data Loading...
