Year
1988
Abstract
The U.S. DOE initiated the Production Risk Evaluation Program (PREP) at Sandia National Laboratories (SNL) to assess quantitatively the potential for serious production disruption as the result of random failures, accidents, natural disasters, or sabotage at its facilities. SNL developed a procedure incorporating both network and fault tree models that identifies production vulnerabilities. For each production step, a steadystate flow model computes the \"critical time,\" which is the maximum period a step can be shut down without preventing the system from achieving production goals. The critical time is then used in fault tree analysis to determine the failure modes that can stop the process for longer than this period. Modular logic modeling is used for constructing the fault trees. Equipment restorable within its critical time need not be considered critical even though it may perform significant work. The PREP models can be used to identify those plant areas to which a saboteur would need to gain access. A security strategy using graded protection could potentially save money. PREP methods also provide quantitative insights to develop protection measures that do not infringe upon the liberties of personnel or complicate work practices.