Heat transfer characteristics in lead-bismuth and pressurized water system

In the concept of advanced intermediate heat exchanger (AIHX) an intermediate heat transfer medium with no reactivity between sodium and water is expected, and lead-bismuth eutectic is considered as good candidate. The concept design of lead-bismuth reactor system is conducted. Study of heat transfer characteristics of lead-bismuth in helical tube system is important and an experimental facility was constructed. Heat transfer experiment was carried out in forced convection and natural convection. Heat balance of the loop was found to be very reliable. Very accurate heat transfer equation for lead-bismuth to water at about 280degC was obtained. The present results show 40% lower heat transfer coefficient than Hoe's equation, because of slightly different geometry of cooling tubes. It was found that correlation of temperature fluctuation gives reliable flow velocity in the case of lead-bismuth. (author)