An experimental set-up has been developed to perform slow strain rate tensile (SSRT) tests on tubular 304L stainless steel (SS) specimens in supercritical water (SCW) environment (550 degrees C 250 bar) The supercritical water is circulated inside an internally pressurized tubular specimen mounted into a universal mechanical test rig and heated by a single loop resistance heating furnace The set-up enables in situ monitoring of acoustic emission and electrochemical potential during the SSRT test The SCW environment is found to significantly influence the mechanical performance of the material as a result of corrosion processes A correlation between acoustic emission response and change of electrochemical potential is revealed The findings are compared with preliminary results of tests performed on bulk SS specimens under the same condition in a commercial autoclave The advantages and potentialities of both set-ups are discussed (C) 2010 Elsevier Ltd All rights reserved