Mitigation system selection

McIntosh, R.D. and Nolan, P.F. (2001) Review of the selection and design of mitigation systems for runaway chemical reactions. Journal of Loss Prevention in the Process Industries, 14, 27-42. 

Stavis, J. P., 1991. Practical Considerations for Nozzle Selection in Water Spray HF Mitigation Systems. Paper presented at Petro-Safe 91 Conference, Houston, February. 

This chapter focuses on four examples that have been selected to demonstrate the effects of mitigation measures. These examples are for demonstration purposes only they do not necessarily represent the optimum design of a mitigation system or actual engineering practices. The four mitigation methods that will be described are ... 

The primary objective of mitigation systems is cost-effective reduction of risk. A recommended systematic risk-based approach for the selection... 

Figure 7.23. Risk-based approach selection and evaluation of mitigation systems (G. A. Melhem and P. A. Croce, 1994).

The enterprise shall mitigate system-level risks to include products risks that were assessed to be critical to system development during concept selection. For critical risks associated with products, the enterprise utilizes simulation, scale-model tests, or prototype tests to demonstrate mitigation of risks to an acceptable level. The enterprise should assess subsystem risks and prioritize critical risks based upon probabihty of occurrence and related consequences to cost, schedule, and/or performance. 

This section of the questionnaire explored the types of mitigation systems currently being used by respondents. The most frequently selected options are shown in Table B.l (respondents were allowed to select more than one). 

When asked where future research should focus specifically to enable advances that would help to develop new and/or better mitigation technologies, the top three areas were monitoring (50 percent), coatings (45 percent), and active systems (41 percent) (more than one option could be selected). Others suggested sensors (29 percent), passive systems (21 percent), and other (21 percent). Improvement in mitigation system lifetime and improvement in the costs of mitigation ranked the lowest (14 percent and 12 percent, respectively). 

The mitigation systems and actions for the Super LWR are selected by reference to LWRs. They are summarized in Table 6.25. The functions of these systems and actions can be categorized into several groups. 

The elimination of a fire hazard may be the ideal solution, but it is often not possible. In general, the optimum level of fire protection is achieved by selecting from the other appropriate prevention and mitigation options. The higher the performance availability (or lower the probability of failure-on-demand) of each selected fire protection feature, the more effective the overall fire protection system. The generally preferred approach to improve effectiveness is to select a combination oipassive and active fire protection features. 

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