Pressurized-Thermal-Shock Test of 6-Inch-Thick Pressure Vessels. PTSE (Pressurized-Thermal-Shock Experiment)-2: Investigation of Low Tearing Resistance and Warm Prestressing.

摘要

The second pressurized-thermal-shock test of a 148-mm-thick steel pressure vessel with a 1-m-long flaw was performed to investigate fracture behavior of a vessel under conditions relevant to a flawed nuclear reactor pressure vessel during an overcooling accident. The objectives were to observe transitional crack behavior in a steel with low tearing resistance and the effects of warm prestressing on crack initiation. Two combinations of pressure and thermal transient conditions were imposed on the vessel with initial vessel temperatures of 300 and 275 C. The crack propagated after being warm prestressed. Warm prestressing elevated the load at fracture significantly. The second transient produced a cleavage crack propagation and arrest followed immediately by unstable tearing. Stable ductile tearing preceded both brittle fractures and also followed the first crack arrest. The final cleavage propagation arrested at high KI levels in spite of the low ductile tearing resistance.