Decontamination of steam generators at Loviisa Nuclear Power Plant

In 1980, during the annual inspection at Loviisa 1 Nuclear Power Station, some minor faults were indicated in the welding seams of the water chambers in two steam generators. This led to more inspection work and to thousands of work--hours inside the steam generators. A decontamination apparatus was quickly designed and constructed. Advice on tested decontamination chemicals was received from the reactor vendor. With the use of the decontamination machine with alternating basic and acid solutions, a decontamination factor of 300 resulted, and the work could be performed without any restrictions on working time