Uncertainty is inherent in almost all aspects of our life. We usually ignore uncertainty to avoid complexity. However solutions so obtained are quite far from the reality and ignoring uncertainty may lead to over (under) estimation. So we need to quantify the uncertainty so as to be aware of the risk involved in any decision making process. Uncertainties can be modeled and analyzed using different theories, viz. Probability theory, Possibility theory, Evidence theory etc. Modeling of an uncertain parameter depends on the nature of the information available. In this paper we have considered uncertainty quantification of parameters in the case of radiological risk assessment. Radiological Risk means, risk associated with the release of radionuclides when radioactive materials are released into the environment. There are various pathways through which radionucliodes can reach human being namely inhalation, ingestion through drinking water and through contaminate food. The main aim of risk assessment is to determine the potential detriment to human health from exposure to a substance or activity that under plausible circumstances can cause to human health. We have analyzed the propagation of the risk both in terms of probability and possibility theory. One advanced method of probabilistic risk assessment (PRAs),viz. P-box method is discussed in this paper. A case study is also carried out with this method and compared with the results taking the parameters of the input distribution of the model as Fuzzy number.

Fuzzy Number Probability-box Probability Bounds Analysis Uncertainty Variability