Assessing the Impact of Equipment Aging on System Performance Using Simulation Modeling Methods

The radiological Inductively Coupled Plasma Mass Spectrometer (ICP-MS) is used to analyze the radioactive samples collected from different radioactive material processing operations at Savannah River Site (SRS). The expeditious processing of these samples is important for safe and reliable operations at SRS. As the radiological (RAD) ICP-MS machine ages, the experience shows that replacement parts and repairs are difficult to obtain on time for reliable operations after 5 years of service. A discrete event model using commercial software EXTEND was prepared to assess the impact on sample turn around times as the ICP-MS gets older. The model was prepared using the sample statistics from the previous 4 years. Machine utilization rates were calculated for the new machine, 5 year old machine, 10 year old machine, and a 12 year old machine. Computer simulations were run for these periods and the sample delay times calculated. The model was validated against the sample statistics collected from the previous 4 quarters. 90% confidence intervals were calculated for the 10^th, 25^th, 50^th, and 90^th quantiles of the samples. The simulation results show that if 50% of the samples are needed on time for efficient site operations, a 10 year old machine could take nearly 50 days longer to process these samples than a 5-year old machine.