An overview of preparatory activities and plant operating experience during dilute chemical decontamination of primary heat transport system in MAPS units 1 and 2

Dilute chemical decontamination of primary heat transport system of Madras Atomic Power Station (MAPS) 1 and 2 units was carried out successfully in December 1993 and April 1995 respectively. The need for such decontamination campaigns had been recognised quite early at MAPS and exploratory work began in 1989 itself. This paper gives an account of work done at MAPS, like identification of the facilities required, inputs to designers regarding site operational requirements and layout/space constraints, preparatory activities preceding the first campaign in unit-1, the procedure used along with the experiences during the actual campaign. Changes brought about for unit-2 based on operating experience in unit-1 and further improvements that are desirable are presented. (author)