Assessment of operational risk of steam turbine valves

The paper estimates the technical risk associated with the operation of power machines. The sources of risk are presented with possible scenarios of failures. The risk involving the operation of steam turbine valves is discussed in more detail. The point estimation technique for reliability analysis and the finite element analysis of thermal stresses are applied. Calculations of the probability of failure are made for random loads and random properties of materials. On the basis of the real data, mean values of stresses and strains under transient operating conditions were calculated, as well as the level of stresses under creep conditions. The calculated values were used for estimation of the probability of valve failure and the value of technical risk