DEPOSITION SLUDGE PHYSICAL AND CHEMICAL CLEANING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a method for efficiently removing deposition sludge deposited on a facility and an appliance such as a steam generator, a boiler, and a heat exchanger used in a nuclear plant.SOLUTION: Treatment target materials are immersed in a cleaning liquid containing at least one kind selected from NH, ETA (mono-ethanol-amine) and NH. Then, temperature and pressure of the cleaning liquid is changed for generating bubbles in the cleaning liquid. In addition, for promoting removal of sludge, temperature of the cleaning liquid is increased. An ETA or NHamount in the cleaning liquid is adjusted so that pH of the cleaning liquid is 7.5-9.5, and concentration of NHin the cleaning liquid is 20 ppb-0.1%.