| Containment vessel of nuclear power plant is the last protective barrier to prevent the leakage of radioactive materials into the surrounding environment,so its importance is self-evident.In order to investigate the dynamic response characteristics and failure mechanism of the CPR1000 prestressed concrete containment vessel(PCCV)structure under earthquakes and impact loads,a series of shaking table tests and impact tests of a 1/20 scale concrete containment vessel(CCV)model which was designed and constructed based on the similitude requirements from the Buckingham's ?-Theorem were carried out.A mixed material was developed to construct the model containment vessel.The main research contents and conclusions of this paper are as follows:(1)A mixed material was developed by mixing cement,ore powder,barite powder,barite sand,and water together in a specific ratio based on the similitude requirements from the Buckingham's ?-Theorem.The specimen tests for the mixed material,including cube splitting tests,three/four-point-bending tests,free vibration tests of cantilever beam,were conducted to study the relationship between the material parameters,such as Young's modulus,tensile strength,ultimate tensile strain,compressive and tensile fracture failure mode,dynamic Young's modulus,and so on,and mix proportion,curing time,as well as ambient temperature.The material tests showed that the mixed material is basically similar with the prototype concrete and could adequately meet the similitude requirements for the dynamic failure model tests of containment vessel.(2)A 1/20 scale model CCV was constructed on the shaking table at Dalian University of Technology(DUT)by employing the mixed material.The horizontal and vertical earthquake waves generated from RG1.60 spectrum were loaded step by step until the macroscopic failure occurred in the model containment vessel.The model test results showed that the maximum acceleration magnification factor of the model CCV was 1.974(0.2g case,horizontal direction).Until the second last test case with the horizontal peak earthquake motion of 0.9g(corresponding to 0.9g for the prototype structure),the model CCV only had slight damage,and the model as a whole was still within the elastic range.In the last case with the horizontal peak earthquake motion of 1.2g(corresponding to 1.2g for the prototype structure),a circle of cracks occurred at the cylinder wall heel of the model containment vessel,which meant that rupture failure had occurred and the cylinder wall heel of the CCV is the weak region under earthquake.Although a circle of concrete cracks appeared around the cylinder wall foot,the model CCV still remained integral as a whole and neither cracking parts dislocation nor collapse occurred.Because the test model was a plain concrete structure and the model test results should be conservative estimation,it can be concluded that the prototype PCCV for CPR1000 nuclear power plant had sufficient seismic safety margin.(3)In order to investigate the response of containment vessel subjected to impact loads,a series of impact tests of the 1/20 scale model CCV were conducted.The equivalent similar models of the small aircraft(Xin Zhou MA600)and large commercial aircraft(Boeing 737-800)were selected as the model aircrafts for the impact tests.The model test results showed that under the impact of small aircraft,local punching shear failure of the containment vessel structure occurred and the structural elastic integrity remained;under the first impact of large commercial aircraft,large number of macroscopic cracks occurred,but basic integrity maintained and neither integral destruction nor collapse occurred,while under the second impact,the containment vessel was collapsed.The prototype PCCV for CPR1000 nuclear power plant had a good impact-resistant ability against large aircrafts. |
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