Dynamic risk assessment for atex zone installations

Abstract

Risk assessment in the nuclear and chemical/petrochemical facilities is becoming a key to the engineering activity, which is necessary to optimize protective layers to limit societal and individual risks. Risk assessment related to the protection engineering discipline usually involves two parts: (1) deterministic analysis based on dynamic process modeling with the goal of verifying the protection design and (2) Probabilistic analysis, aiming to assess the frequency of consequences of accidents outside the design basis. This work deals with the two parts mentioned above in order to extend the experience of nuclear and chemical/petrochemical industries into a common risk analysis aiming in the _rst part at modeling the chemically reacting processes within explosive atmospheres installations using deterministic tool analysis based on thermodynamic and chemical reactions modeling. There are some similarities between Bhopal disaster, the Chernobyl accident and TMI, the phenomenology is similar in that the temperature and the pressure caused by exothermic reactions had increased dramatically leading to a loss of containment. The second part aims to develop an adequate computing tool for the transient simulations to _nd damage domains and calculate their exceedance frequencies, i.e. identify those transients within a sequence that lead to damage and calculate the exceeding frequency of the contribution of all paths within the sequence. More speci_cally, this work aims to develop an adequate Dynamic Risk Assessment (DRA) model through a simpli_ed case of Methyl-Isocyanate explosion scenario inside the storage tank 610 of the Bhopal plant. A comparison with a similar scenario (i.e. compartment containment analysis of H2 deagrations) in the nuclear industry is also made to show the feasibility of a common DRA