One of the obstacles that is inhibiting the development of supercritical water oxidation (SCWO) into a viable industrial process, is the problem of corrosion. A bench scale stainless steel flow reactor for supercritical water oxidation studies was constructed. Corrosion of the reactor was studied under pressure of 400 bars and at temperatures of 250, 375 and 420 degreesC. The concentrations of various metals in the effluent were monitored by flame atomic absorption spectrometry. Higher corrosion rates were observed at 375 degreesC, or near the critical temperature. Addition of hydrogen peroxide also significantly increases the corrosion of stainless steel. Exposure of the reactor to open air between experiments is also found to be a contributing factor to the corrosion of SCWO experiment. (C) 2002 Elsevier Science B.V. All rights reserved.