In October 2015, JIS B8223 (Boiler feedwater and boiler water quality standards) was
revised and issued, and for the Heat Recovery Steam Generator (HRSG) of combined cycle plant,
the operational standards for High-AVT (high pH) water treatment that Mitsubishi Hitachi Power
Systems, Ltd. (MHPS) has applied at actual plants since 2001 were adopted. High-AVT water
treatment has been increasingly applied as a measure against Flow Accelerated Corrosion and
phosphate corrosion problems both inside and outside Japan and is useful as an alternative
technology to hydrazine, the carcinogenicity of which has been pointed out. In addition, from an
economic point of view, the advantages of the adoption of High-AVT water treatment, such as the
shortening of plant start-up time and the reduction of operating costs, have been verified.
