Study On Localization Of The 850-Ton Large Scale Hydraulic Snubber For Nuclear Power Plants

Hydraulic snubber is one of the important safety protection devices for mechanical equipments in the nuclear power plants.During normal operation,it does not confine thermal displacement of equipments or piping without applying external force.When equipments or piping are subjected the impact loading with a sudden change such as earthquakes or pipe whips,its velocity will suddenly increase.The lift valve of the hydraulic snubber will close and instantly become an approximate rigid structure to support equipments or piping when it moves faster than the locking speed,to prevent them from being damaged by impact load.As the domestic manufactures started relatively late on the design and manufacturing of the hydraulic snubber,the techniques are not yet mature especially for large scale hydraulic snubbers,which resulted in a fact that most snubbers mainly relies on import currently.In order to realize localization of large scale hydraulic snubbers for nuclear power plants,and meet the requirements of China’s Nuclear Long-and-medium Term Development Planning,it is significant to conduct in-depth study on design,manufacturing and performance testing of the large scale hydraulic snubber.The 850-ton large scale hydraulic snubber used for steam generator support in CAP1400 PWR will be studied as a research subject in this paper.Firstly,a complete design proposal is put forward in this paper with overall considerations in structure design scheme,material selection of main parts and load capacity according to the actual design load.Secondly,a 1:1 model prototype of the snubber is designed and manufactured by an experienced domestic manufacturer,and the test procedures of static functional test,dynamic functional test and environmental test with testing results are also studied.Further analysis indicates that testing results can meet the requirements of engineering application,which fills the domestic blank.