Measuring subcooled boiling heat transfer on a CuCrZr surface to predict durability of a heat sink material for plasma-facing components

Abstract

Energy conversion and heat transport are essential technologies for developing a commercial fusion reactor. In particular, plasma-facing components are a key to safety and effective operation. The heat transfer performance of plasma-facing components has been investigated. Boiling heat transfer is a promising method to economically cool a high heat flux in plasma-facing components because the latent heat of vaporization is high, resulting in a high heat transfer coefficient. As a result, less pumping power is needed than in single-phase flow cooling. In the event of a power loss, thermosiphons with pool boiling can be used for emergency cooling. In fusion reactors, copper-chromium-zirconium (CuCrZr) is expected to be used as a heat sink material for plasma-facing components. The surface properties of a heat sink affects boiling heat transfer. Cooling fusion reactors with boiling heat transfer requires investigating boiling characteristics on a CuCrZr surface, including critical heat flux (CHF). To characterize boiling heat transfer with CuCrZr, this study examined subcooled pool boiling with water at atmospheric pressure by varying the liquid subcooling temperature. The experimental results reveal that the CHF does not deteriorate with CuCrZr as it does with copper.