| High-level radioactive waste liquid evaporator is used for concentratingthe high-level radioactive waste in a nuclear power station so that to theamount of the radioactive waste to be treated is reduced. It is also helpful forthe rercycle use of the radionuclide and the nitric acid. Obviously, it isimportant to guarantee the safety of high radioactive waste liquid evaporatorin service. Specifically, the equipment should be able to operate under theOBE condition and should be shut down safely under the SSE condition. Inthis thesis, seismic safety analysis was carried out for the high-levelradioactive waste liquid evaporator. The main contents are as follows.First of all, in this thesis, seismic spectrum analysis for the evaporatormade by special material was carried out with the finite element softwareANSYS. The whole finite element model including the pipe from the firstfixed pipe support to the nozzle wedded to the evaporator is established so thatthe problem of lacking nozzle load data can be solved. After performing modeanalysis and spectrum analysis, stress distributions of the structure under theaction of design, abnormal and accident loading cases are obtained and safetyassessment for the structure is completed based on Design And Construction Rules for Mechanical Components of PWR Nuclear Islands RCC-M.Secondly, seismic time-history analysis for high-level radioactive wasteliquid evaporator was also conducted. Displacement time history andmovement trajectory at typical positions are obtained. Also founded are thechanging of the stress intensity concentration over time and the stressdistribution at the most dangerous moment in the process of earthquake.Finally, comparing the results obtained by spectrum analysis andtime-history analysis, it is found that the former is more conservative than thelatter. |
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