In the paper, the assessment of safety of the pipelines elements from the heat and power generating plants of Ukraine made of l 2Kh I MF steel has been presented. The SINT AP procedures for failure assessment have been performed assuming two shapes of hypothetical cracks along the straight segments of pipeline. The thermal stresses during the cooling process have been taken into account in the analysis. The analysis has been performed at the first level of SINT AP procedures. Two stages: a) before pipeline operation and b) after 156000 hours of service work have been analyzed. The comparison of results obtained by other assessment method has been made.