Preventive Maintenance Task Selection and Implementation

DOE-STD-1052-93

failure causes and mechanisms

failure rates as compared to the industry if easily retrievable and available

Although plant data is weighed more heavily, failure data from other sources should

also be used. Newer plants may have to rely more on industry experience. This data

should be reviewed closely to determine that failure modes and causes are plausible

and coded correctly. DOE Notices and Bulletins are valuable sources of failure

information. Component failure analysis reports should be used and failure rate data

may be helpful in evaluating failure history. Unacceptable levels of corrective

maintenance noted on a component may indicate problems with maintenance work

practices, inadequate procedures, spare parts, or inappropriate design. Corrective

actions for these causes of problems should be addressed on a case-by-case basis

rather than considering additional PM tasks.

Much of the information collected may be validated and additional perspective gained

from interviews with key operating, maintenance, engineering, and vendor personnel.

Information gained by interviews should be compared with the history data to ensure

all known failures and reliability . problems are identified for analysis.

8. PREVENTIVE MAINTENANCE TASK SELECTION AND IMPLEMENTATION

This section discusses the selection and implementation of applicable and effective PM tasks.

To accomplish this effort, significant failure modes identified from the FMEA are evaluated

using a logic tree analysis to classify the importance of the failure modes. This information

is then used to recommend applicable and effective PM tasks or design changes. The

recommended PM tasks are compared to the existing PM tasks to determine if the new tasks

should be implemented or if the existing tasks should be modified or deleted. This section

also discusses development of an integrated project plan to implement the recommended PM

tasks.

8.1

Logic Tree Analysis

A decision or logic tree analysis (LTA) process, may be used to determine the

importance of each significant failure mode and aid in the selection of applicable and

effective preventive maintenance tasks. The logic tree requires the analyst to answer

"yes" or "no" to a series of questions. These answers should determine the decision

path. The analyst starts by evaluating if the failure mode is visible or evident to the

operating crew. The analyst then determines the consequence and importance of the

component functional failure. After determining the consequences and importance

of the failure, an applicable and effective PM task is selected or a design change may

be necessary. The following questions may be used in the logic tree process:

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