Seismic Safety Analysis Of Pulse Sieve Plate Extraction Column

Nuclear safety has always been a matter of public concern,since the Fukushima nuclear accident,the seismic performance of nuclear equipment has become a hot topic for many scholars.For the spent fuel reprocessing equipment,China does not have a perfect design and manufacturing standard.Therefore,whether the reprocessing equipment can ensure the safety during the earthquake also needs more in-depth research.In this paper,the seismic safety analysis of the pulsed sieve plate extraction column of the nuclear fuel reprocessing plant was carried out by ANSYS software.The stress and deformation results of the equipment under different levels of earthquake were obtained by finite element analysis.The results are checked by the French RCC-M standard.The specific work content is as follows:(1)The complete finite element model of the pulsed sieve plate extraction column was established using the ANSYS APDL module and simplified reasonably.The device is mainly composed of four parts: the upper clarification chamber,the pulse tube,the lower clarification chamber and the sieve plate in the pulse tube.At the same time,the paper also draws an external bracket,which is connected by a plurality of support plates and flanges and a pulse extraction column.The interface with a diameter of less than 50 mm was neglected during the modeling.The final model was about 11.7 meters high and the total number of cells reached 286,963.(2)According to the operating condition and installation mode of the equipment,the loads and constraints to be applied are determined.Then the static structure analysis of the equipment is carried out under the corresponding load combination,the stress and deformation of the equipment under the design condition are determined,and its strength is checked.Selecting the appropriate modal analysis method to extract the natural frequencies and modes of the first twenty orders,this paper lists the first eight modes.(3)In this paper,the stress and deformation of the pulse sieve plate extraction column during the earthquake are checked.Then,ANSYS dynamic spectrum analysis module is used to simulate and calculate the stress and deformation under abnormal working conditions(when OBE earthquake occurs)and accident working conditions(when SSE earthquake occurs)respectively when the equipment is under no load(ie,in non-operating state)and full load((ie,in running state).The calculation results are checked with the RCC-M standard,it was found that the stress of the pressure component,the stress of the plate support,the stress of the linear support,and the weld strength on the plate support were all in compliance with the regulations.The pulse sieve plate extraction column operates normally at the earthquake of the OBE level and can safely stop operating at the SSE level.In addition,it can be seen from the stress calculation results that the weakest part of the whole equipment is the position where the pulse tube is connected with the upper and lower clarification chamber.