The Japan Atomic Energy Agency has been conducting research and development on the thermo-chemical iodine-sulfur (IS) process, which is one of the most attractive water-splitting hydrogen production methods that uses nuclear thermal energy. The sulfuric acid decomposer is one of the key components of the IS process. The boiling heat transfer coefficients of sulfuric acid solutions are required to design the sulfuric acid decomposer. These coefficients were measured in aqueous solutions where the mole fraction of H2O ranged from 0.17 to 0.37 (heat flux range from 16.9 kW/m(2) to 5.6 kW/m(2)) and compared with the empirical correlations formulated for binary mixtures. A combination of the Stephan-Korner correlation, using the empirical constant A(o) = 2.00, and the Nishikawa-Fujita correlation was used to predict the experimental results with an accuracy of +/- 10%. (C) 2013 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.