Monte Carlo Method for Uncertainty Analysis of HTGR Accident Consequences

A method for propagating the uncertainties in the prediction of postulated accident consequences was devised. The method uses simplified mathematical models, derived from first principles and detailed deterministic computer model results to describe controlling physical processes in the transport of radioactive material from the plant and resulting population doses and health effects. These simplified models are used in a computationally efficient Monte Carlo error propagation technique. The approach is shown to be useful for uncertainty analysis of core heatup accidents postulated for the High Temperature Gas-Cooled Reactor. In combination with accident frequency predictions, the method provides the complementary cumulative risk curves typically used to present the final results of a risk assessment study