Evaluation of thermal striping damage for a tee-junction of LMR secondary piping

This paper presents the thermomechanical and fracture mechanics evaluation procedure of thermal striping damage on the secondary piping of LMFR using Green's function method and standard FEM. The thermohydraulic loading conditions used in the present analysis are simplified sinusoidal thermal loads and the random type data thermal load. The thermomechanical fatigue damage was evaluated according to ASME code subsection NH. The analysis results of fatigue for the sinusoidal and random load cases show that fatigue failure would occur at a geometrically discontinuous location during 90,000 hours of operation. The fracture mechanics analysis showed that the crack would be initiated at an early stage of the operation. The fatigue crack was evaluated to propagate up to 5 mm along the thickness direction during the first 944 and 1083 hours of operation for the sinusoidal and the random loading cases, respectively