Systematic approach for assessment of accident risks in chemical and nuclear processing

The industrial accidents which occurred in the last years, particularly in the 80's, contributed a significant way to draw the attention of the government, industry and the society as a whole to the mechanisms for preventing events that could affect people's safety and the environment quality. Techniques and methods extensively used the nuclear, aeronautic and war industries so far were adapted to performing analysis and evaluation of the risks associated to other industrial activities, especially in the petroleum, chemistry and petrochemical areas. The risk analysis in industrial facilities is carried out through the evaluation of the probability or frequency of the accidents and their consequences. However, no systematized methodology that could supply the tools for identifying possible accidents likely to take place in an installation is available in the literature. Neither existing are methodologies for the identification of the models for evaluation of the accidents' consequences nor for the selection of the available techniques for qualitative or quantitative analysis of the possibility of occurrence of the accident being focused. The objective of this work is to develop and implement a methodology for identification of the risks of accidents in chemical and nuclear processing facilities as well as for the evaluation of their consequences on persons. For the development of the methodology, the main possible accidents that could occur in such installations were identified and the qualitative and quantitative techniques available for the identification of the risks and for the evaluation of the consequences of each identified accidents were selected. The use of the methodology was illustrated by applying it in two case examples adapted from the literature, involving accidents with inflammable, explosives, and radioactive materials. The computer code MRA - Methodology for Risk Assessment was developed using DELPHI, version 5.0, with the purpose of systematizing and automating the application of the methodology. (author)