In order to meet the cooling needs of high heat flux (HHF) internal plasma facing components (PFC) of fusion reactor, experimental investigations of hypervapotron (HV) heat transfer enhancement with the alumina-water nanofluids were carried out. Pressure water hypervapotron loop-II (PWHL-II) has been constructed to implement the high heat flux HV heat transfer correlative experiments for PFC. The triangular fins in HV test section of chromium-zirconium-copper alloy were processed similar to the International Thermonuclear Experimental Reactor like (ITER-like) divertor targets and the Neutral Beam Injector (NBI) cooling components. 200 KW high frequency induction heating equipment was developed to use as the power source of HHF. Alumina-water nanofluids of four different mass fractions were prepared by ultrasonic dispersion technology. The experiments of heat transfer enhancement measurement have been completed. Real-time temperature data of the four specified positions at the root of HV fins were acquired by the temperature sensors and used to analyze the heat transfer performance enhancement under each of the corresponding conditions. Experimental results show that the HV heat transfer performance enhancement with the mass fraction 0.01% alumina-water nanofluids is better than that of the mass fraction of 0.005%, 0.05% and 0.10% alumina-water nanofluids as well as deionized water under HHF and different flow velocities. In the cases of high flow velocity at different heat flux, the heat transfer enhancement of the 0.01% alumina-water nanofluids in HV increases by 17% on average and 31% at most in comparison with deionized water. In the case of HHF, the heat transfer enhancement of the 0.01% alumina-water nanofluids in HV increases by 21% on average and 30% at most in comparison with deionized water. The results in question can function as a reference for design optimization and improvements of the ITER-like devices' water cooling structure of the HHF plasma facing components for future fusion reactors. (C) 2016 Elsevier Ltd. All rights reserved.