The need to operate thermal systems, including those in nuclear power plants, below the critical heat flux (CHF) requires inconvenient compromises between economy and safety. This has led to much research aimed at enhancing the CHF. CHF enhancement was recently noticed in nanofluids where the heating surface was fouled by nanoparticles. We attempted to imitate the micro/nano multi-scale structure of nanoparticle fouling by surface modification. In this study, surface treatment was used to change the surface wettability of a Zircaloy-4 heater. A pool boiling apparatus was developed based on the results of the surface treatment, and an experimental study was performed to investigate the increase in CHF.