Planning and Scheduling Outages

The main objective of a shutdown is to accomplish, at the lowest possible costs, the maximum quality and quantity of work that can be completed within a limited time, defined as the outage. Shutdown activities should be concentrated on work that can only be performed during shutdown or when production systems are idle. A well-organized and adequately planned and scheduled shutdown is the best insurance for lower maintenance and high reliability of equipment. 

This fact is not designed to take away from the importance of either one. The good news is that the mechanics of planning and scheduling is the same for either daily/weekly or shutdown/project maintenance. Well planned work orders are the fundamental requirement of both routine and outage maintenance. Many organizations lose sight of this fact. 

Effective shutdown management depends on absolute adherence to prescribed standards that define what type of work will be done during scheduled shutdowns. These decisions can not be made by the maintenance planner alone. To aid in the selection, planning and implementation of outage tasks, a management team is a fundamental requirement. This team should be composed of ... 

The main scheduled outage took place during die second quarter of 1996 and was devoted to the replacement of 21 control rods and to annual maintenance operations. Performed as planned, it was followed by a series of neutron tests, then by a period of waiting for a restart authorization from the Safety Authority. 

Availability and reliability have a very major impact on the plant economy. Reliability is essential in that when the power is needed it must be there. When the power is not available it must be generated or purchased, and can be very costly in the operation of a plant. Planned outages are scheduled for non-peak periods. Peak periods is when the majority of the income is generated as usually there are various tiers of pricing depending on the demand. Many power purchase agreements have clauses, which contain capacity payments, thus making plant availability critical in the economics of the plant. 

The addition of predictive maintenance techniques as an outage-scheduling tool reduced the outage to five days and resulted in a total savings of 200,000. The predictive maintenance data eliminated the need for many of the repairs that would normally have been included in the maintenance outage. Based on the ball mill s actual condition, these repairs were not needed. The additional ability to schedule the required repairs, gather required tools and plan the work reduced the time required from three weeks to five days. 

The Nova rupture risk FTA is normally performed for the review and analytical examination of systems or equipment to emphasize the lower-level fault occurrences, and the results of the FTA calculations are regularly validated with inspection results. These results also serve to schedule maintenance operations, conduct surveys, and plan research and development efforts. Figure 5 presents the uniform corrosion branch pipeline outage FTA system. Each element of the branch in this figure contains numeric probability information related to technical and historical data for each segment of the 18 000 km pipeline. In some cases, it is simpler to assume some probability... 

Administrative improvements related to the mitigation systems include mainly a more systematic approach to outage planning where umbrella schedules are being developed covering a series of systems, to prevent opposing unavailability of trains of front line systems and support systems. 

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