METHOD FOR CHEMICAL WASHING OF PWR STEAM GENERATOR

摘要

PURPOSE:To enable prevention of elution of a radioactive material deposited and remaining inside a tube by a method wherein the internal pressure of a steam generator is kept high, a washing liquid is filled at normal temperatures inside the steam generator and thereafter the pressure inside the steam generator is reduced. CONSTITUTION:Since the amount of elution becomes large at a high temperature, a washing liquid 4 is filled inside a steam generator 1 at normal temperatures whereat the amount of elution is small relatively. On the occasion, the pressure inside the steam generator 1 is kept high. After the washing liquid is filled, it flows a little into a residue extracting tube 2. At this time, a gas inside the residue extracting tube 2 is at a high pressure. By reducing the internal pressure of the steam generator 1, accordingly, the washing liquid 4 flowing into the residue extracting tube 2 is released outside the tube 2. When the temperature of the washing liquid 4 is raised thereafter, the washing liquid does not flow into the residue extracting tube 2. According to this constitution, the elution of a radioactive material deposited and remaining inside the tube can be prevented.