NSGI

Your Predictive/Condition Based Maintenance Program

Tuesday, July 26th, 2011 | Condition Monitoirng & Predictive Maintenance | 8 Comments

The purpose of a predictive/condition based maintenance (PdM/CBM) program is to communicate information about the condition of the machinery under surveillance. The PdM/CBM report should include only information that helps the reader to clearly understand the results of the condition monitoring efforts. The report should include:

• An equipment status report including operating availability and component availability
• A priority work list including work pending, work in progress, and work completed
• Status definitions for satisfactory, marginal, and critical
• A summary of the operating status of each component to include fully operational, marginal, critical, and inoperable

Individual equipment status reports for equipment that is marginal or worse

The report serves two primary functions:

1. It provides a valuable source of information for plant maintenance, operations, and engineering.
2. It continually shows the impact of PdM/CBM on the plant to upper management. This line of communication justifies the program and allows for continued management support.

 

The reporting period is determined by the needs of the plant but a report should be prepared at least annually. It is important to note that the report should not contain any raw data collected from a diagnostic system. It should be concise and clear.

 

 

The following elements should be included in a PdM/CBM periodic report:

• Management summary – Provides a synopsis that highlights the activities performed during the reporting period. When possible, use photographs of actual plant conditions that illustrate successes.
• Equipment performance – Provides a list of equipment that predictive maintenance indicates is in an abnormal condition and has been placed on an alert or watch list.
  • Windows® format and supporting documentation can be used to identify equipment condition. Also indicate in this section those pieces of equipment that have been removed from the alert or watch list.
  • Information sharing – Provides a section to be used by predictive maintenance personnel to explain various aspects of the program or to share examples where assistance has been provided to other station departments.
  • Cost-benefit – Provides cost savings that are attributed to predictive maintenance activities. Consider costs that were avoided because equipment replacement, maintenance labor hours, and purchase of replacement power were not needed.
  • Continuous improvement and operating experience – Provides discussions on new technologies and training received by predictive maintenance personnel. This section could also be used to document any internal or external examples of operating experience factored into the predictive maintenance program.

 

Program Metrics

All nuclear plants have extensive goals and metrics to indicate effectiveness of plant programs and processes and to measure progress toward desired improvements. These metrics do not always relate to the effectiveness and progress of the PdM/CBM program itself. Therefore, it is useful to have a clearly defined set of performance measures that specifically relate to the PdM/CBM process.

 

A Best practice set of metrics is as follows:

• Focus on four important cost areas:
  • Equipment reliability and unit availability
  • Operations and maintenance costs
  • Capital expenditures
  • Thermal unit performance
  • Maintenance task balance between unplanned corrective maintenance tasks (which are reactive), planned CM on run-to-failure equipment, repetitive PM tasks, and condition directed tasks, which are planned CM or PM tasks initiated as a result of decisions from the PdM/CBM process. Planned CM is defined as a situation where either the equipment has been predetermined as run-to-failure, or condition monitoring has detected degradation of the equipment and allowed time for proper planning and optimum scheduling of the task.
  • Return on investment for PdM/CBM activities.
  • Effectiveness in implementing the PdM/CBM process

PdM/CBM Key Performance Indicators

Performance Parameter	Indicator	Target
Data Collection	Number of delinquent data collection PMs	0
	Number of surveillance tests repeated due to errant vibration data	0
	Percentage data collection of total PdM/CBM components – Motor Analysis Program	100%
	Percentage data collection of available PdM/CBM components – Motor Analysis Program	100%
	Percentage data collection of total PdM/CBM components – Thermography Program	95%
	Percentage data collection of available PdM/CBM components – Thermography Program	98%
	Percentage data collection of total PdM/CBM components – Vibration Program	95%
	Percentage data collection of available PdM/CBM components – Vibration Program	98%
Data Analysis	Number of occurrences of unidentified equipment degradation within PdM/CBM scope	0
	Lube oil sample backlog	80% ≤ 2 weeks 0% > 4 weeks
Equipment Reliability	Percentage of undetected failures of PdM/CBM scope components	<1.0%

 

Tags: CBM, Condition Based Maintenance, condition monitoring, PdM, Predictive Maintenance