Research On Processing Key Problems Of Nuclear Steel A508-ⅢCompact Tension Specimen Based On Master Curve Approach

With the rapid development of the nuclear power industry in China, the safe running of Nuclear power plant is particularly important. In order to ensure the normal operation of the reactor pressure vessel, the three generation of advanced pressurized water reactor nuclear power plant such as the new AP1000, the technical requirements prescribed that fracture toughness specimen should be placed in the reactor irradiation monitoring samples. At present, the method of material fracture toughnessresearch is new developed Master Curve method. But the compact tension specimen processing technology was really complicated, especially the prefabricated fatigue crack stage often spend a lot of manpower and material resources. In addition, in the American and China standard, the requirements and regulations of crack propagation rate in prefabricated fatigue crack stage and side grooves effects on fracture toughness test and crack morphology are a little bit fuzzy. In this paper, focused on nuclear reactor pressure vessel steelA508-III, the key problems of the processing technology of the compact tensile specimen in Master Curve method were studied. The main cotents and conclusion of this paper are as follows:(1) Focused on the compact tensile specimen of domestic A508-III steel, fatigue crackextension test under the load of prefabricated fatigue crack was researched. Combined with fatigue crack closure effect, the Paris formula which fatigue crack extension at low speed was fitted.(2) The influence of side grooves for 0.5T C(T) specimen fracture crack morphology was analysised. Including the initial crack lengtha0, depth of tunnel and crack front straightness. Combined with the existed prefabricated crack technology, the appropriate improvement scheme was proposed in order to improve the efficiency and success of the test and reduce the test cost.(3) Based on Master Curve method, the reference temperature To for 0.5T C(T) specimen with side grooves was calculated through the fracture toughness test. The difference between Tofor specimen with side grooves and specimen without side grooves was compared.