Patent ID: 7857911

Claim:
A method of conditioning and removing scale and deposits within a heat exchange system that utilizes at least one heat transfer liquid comprising: taking the heat exchange system out of service; removing at least a portion of the heat transfer liquid from the heat exchange system; introducing an aqueous cleaning solution of a scale conditioning agent into the heat exchange system, wherein the scale conditioning agent comprising a chelant, the chelant being present in the aqueous cleaning solution at a treatment concentration that is higher than 1 weight percent and less than or equal to about 2 weight percent; maintaining the aqueous cleaning solution at a treatment temperature; maintaining the aqueous cleaning solution at a treatment pH that is higher than 9.0 and less than or equal to 11.0; removing substantially all of the aqueous cleaning solution from the heat exchange system; introducing replacement heat transfer liquid; and returning the heat exchange system to service, wherein the heat exchange system comprises a steam generator of a nuclear power plant, wherein the method is performed without using a corrosion inhibitor.