Life duration assessments of power station plants require also an approximately exact calculation of the operational stresses. The article deals with the stress determination in a pipe bend under internal pressure in the creep range by using a simplified non-elastic analysis. It is based on an analogue consideration between plasticization and creep. The rearrangement of the primary stresses due to creep is correctly described for a pipe bend made of the material 14 MoV 6 3. and leads to a lower stress level, compared to elastic-determined values. The influence on the life duration assessment is considerable and is shown on an example.