In order to investigate the heat transfer characteristics of hypervatron in the divertor dome of the International Thermonuclear Experimental Reactor (ITER), the off-center electrically heating method was used simulate the one-side heating condition in the engineering application. The heat transfer experiments of subcooled water were carried out in a vertically upward hypervapotron under the system parameters as follows: system pressure P = 2.7, 3.2, 3.7 MPa, mass flux G = 2000-5000 kg.m(-2).s(-1), and equivalent one-side radiating heat flux q(e) = 2-5 MW.m(-2). The effects of parameters on heat transfer were discussed in detail. The results show that the heat transfer coefficient h is significantly affected by G in the single phase (SP) region; the h is synthetically influenced by P, G, q in the partially boiling (PB) region; the h is only affected by q in the fully developed boiling (FDB) region. The experimental data were compared with the typical correlations in single phase region and subcooled boiling region, respectively. The results show that the Dittus-Boelter correlation and the modified Shah correlation have good agreement with the experimental data. The typical CHF correlations for smooth tubes were assessed by the CHF data, the results indicate that experimental Bo(cr) are overpredicted by most CHF correlations, so it can be speculated that the hypervapotron can obtain higher CHF values than smooth tubes. (C) 2018 Elsevier Ltd. All rights reserved.