Failure Prediction of Irradiated Fuel Rod in Nuclear Reactors Under Reactivity-Initiated Accidents by Means of Statistical Approach

Abstract

During the last decade, RIA behavior of high-burnup fuel rod has been of great concern in nuclear safety since there is an evidence of.fuel rod failures at unexpectedly low enthalpy values. A statistics-based methodology was proposed to predict failure probability of irradiated fuel rods. Based on RIA results published in literature, the failure enthalpy of irradiated fuel rod was correlated with oxide thickness, fuel burnup, and pulse width. The 'equivalent enthalpy' was introduced as a single damage parameter characterizing the cladding damage of irradiated fuel rod. The failure probability distribution was represented as a function of equivalent enthalpy applying a two-parameter Weibull statistical model. Lifetime prediction was attempted using the developed methodology to estimate the effects of corrosion, fuel burnup, peak fuel enthalpy and type of cladding materials used.