Reliability centred maintenance - an overview in Indian PHWR context

Over the last few decades, attitude and approach to maintenance has changed very rapidly together with new maintenance techniques, growing awareness of effect of equipment failure on safety and environment and increasing pressure to achieve high plant availability and to contain cost. Broadly, the approach and technique for maintenance are categorized in four groups viz. reactive maintenance, preventive maintenance, predictive maintenance and finally, the latest concept of Reliability Centered Maintenance (RCM). While the reactive maintenance is basically 'run it till it breaks' mode is an old concept for maintenance. In preventive maintenance either a time based schedule or a schedule based on that of machine run time. The goal here is to minimize system and component degradation and thus, sustain or extend the useful life of the equipment. A predictive maintenance approach strives to detect the onset of equipment degradation and differs from preventive by basing maintenance needs on the actual condition of equipment rather than some predetermined schedule. Finally, the Reliability Centered Maintenance (RCM) is the maintenance approach used when following a process that assesses equipment condition and determines the maintenance requirement in operating context. This paper brings out a case study of Reliability Centred Maintenance Technique carried out for Indian PHWR highlighting various aspects of RCM and application of the same. Though this technique of maintenance is not strictly followed presently. This can improve maintenance approach in future. (author)