Probabilistic Radiological Risk Assessments for Radiation Facilities with Vague Information

The objectives of this article are to provide streamlined technique, including the Delphi approach, Bayesian update and two-dimensional Monte Carlo analysis(2D MCA), and to provide information through the investigation of factors in risk model which supports risk assessment for the radiological risk assessment in operation of such radiation facilities with vague information. The scope of this study is restricted to risk assessment. Focus was placed on the framing of probabilistic risk assessment(PRA) procedure applicable to a system for which information on risk contributing factors is vagueness. Incorporation of the Delphi panel method and the Bayesian update into PRA for dealing very uncertain factors was addressed in particular. The PRA methodology established through this study for facilities with vague information on risk contributing factors was applied for risk assessment for field radiography. Task analysis was performed for operations and scenarios based on the risk ranking and relative frequency were constructed for each task in field radiography. The risks for the worker and the public member were estimated by dividing into the normal and accident situations.