Inspection, evaluation and repair of feed water nozzle and replacement of sparger of TAPS unit no. 1 reactor

Experience with worldwide BWR's (boiling water reactors) indicated that since 1974 flaws inside feedwater nozzle did occur as it was a generic problem. At Tarapur Atomic Power Station (TAPS) in both the units, few indications were detected during 1980 nozzle inspection in the blend radius of feed water nozzle, not all of them were necessarily the flaws and periodic inspection of feedwater nozzle was continued till 1987. This report describes the inspection measure started since 1980 up to the actual repair of the feedwater nozzle and replacement of feedwater spargers which were carried out during the regular refuelling outage in 1987 at TAPS Unit no. 1 reactor. The whole repair work took less than six months using totally indigenous technology. (author). 4 refs., 2 tabs., 9 figs