ARES Corporation

Many clients of ARES Corporation need to know the strengths and weaknesses of their systems.  They need information related to the possible failure points in each process and the consequences associated with each fault.  Failure Modes and Effects Analysis (FMEA) or Failure Modes Effect and Criticality Analysis (FMECA) are effective engineering tools for evaluating systems at a number of stages in the design process.  Depending on the project, ARES uses one of the models to answer several questions about the operation and safety of a system and areas where improvements can have substantial impacts on system performance. FMEA/FMECAs also allow for modeling proposed engineering changes to existing systems.

FMEA/FMECAs can be utilized for a variety of reasons, including, but not limited to, determining:

• Identified failure modes which present an unacceptable consequence to facility workers or the public
• System reliability versus throughput rate requirements
• Recommendations for improving the safety and reliability of equipment/processes

In order to answer these questions, ARES first performs an FMEA/FMECA, and then develops reliability block diagrams using the information contained in the FMEA/FMECA and RBDA+ (Reliability Block Diagram Analysis).

ARES conducts their analysis using the guidelines of MIL-STD-1629A. The system being investigated is first broken down into major subsystems, and from there into individual components (e.g., mechanical components, motors, valves, relays, switches, instruments, etc.). If desired, the system can be broken down into parts and pieces for the analysis. Utilizing standard information, engineering experience and engineering judgment, the failure modes for each component are then determined. For each failure mode, the local effects and system-wide effects are then determined and categorized as to severity. In addition, mitigating features of the design and methods of detecting a failure are also identified in the analysis. All of this information is recorded on an FMEA/FMECA worksheet. An example worksheet for the Multi-Canister Overpack Handling Machine (MHM; a large crane in a radioactive waste storage facility) is shown below. The information gathered on the individual components can then used to build the reliability block diagrams for the RAM analysis.

An Example of the Results of this Process is Shown Below:

This rigorous application of FMEA/FMECA has been utilized on such projects as:

• Large crane reliability assessments for critical processing facilities
• Selection of process equipment redundancy systems for radioactive waste handling facilities
• Determination of probable throughput over extended periods in waste handling operating facilities

This approach offers opportunities for our clients to minimize initial costs, achieve a comprehensive understanding of failure modes and probabilities and prepare a tailored maintenance approach to achieve reliability goals.