In this paper, the uncertainty in the operational behavior of an industrial system has been analysed using Intuitionistic Fuzzy Set (IFS) Theory. The performance of systems depends on various reliability parameters such as system failure rate, mean time to repair (MTTR), mean time between failures (MTBF), expected number of failures (ENOF), system reliability and availability. Therefore it is necessary for plant personnel to have relevant information about these parameters. As primary data related to failure and repair time are extracted from literature/experiments/expert opinions it may contain some uncertainty and impreciseness. To deal with the impreciseness and explore the information about the system parameters, IFS theory has been incorporated here. In this study, the behavior analysis and reliability measures of TAB Manufacturing Plant are discussed by Vague Lambda-Tau (VLT) method which is based on IFS theory and lambda-tau technique. The objective of this study is to analyse and find more information about reliability indices and to show the importance of Vague Lambda-Tau method over Fuzzy Lambda-Tau method. For this purpose, all the system parameter-values are obtained by Fuzzy Lambda-Tau method and are compared with Vague Lambda-Tau method values. The uncertainty analysis, done here will help the decision analyst to achieve better system maintenance strategy for failure-free operation of the system.