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Conference Article: Tee-junction of LMFR secondary circuit involving thermal, thermomechanical and fracture mechanics assessment on a striping phenomenon

Lee, H.-Y.; Kim, J.-B.; Yoo, B. (Korea Atomic Energy Research Institute (Korea, Republic of))

Abstract

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 thermal loads. The thermomechanical fatigue damage was evaluated according to ASME code subsection NH. The results of fatigue analysis for the sinusoidal and random type load cases showed that fatigue failure would occur at a welded joint during 90 000 hours of operation. The assessment for the fracture behavior of the welded joint 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 940.7 and 42 698.9 hours of operation for the sinusoidal and the random loading cases, respectively. However, it was evaluated that the crack would be arrested because of the low level of the primary stresses. The fatigue and crack propagation analyses for the random type loads were performed by Green's function method.

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key words: crack propagation; fracture mechanics; green function; lmfbr type reactors; secondary coolant circuits; thermal analysis; thermal fatigue; thermal stresses; welded joints
Reference:
Final report of a co-ordinated research project 1996-1999
International Atomic Energy Agency, Vienna (Austria)
IAEA-TECDOC--1318, pp:153-167