核电厂海水蝶阀密封圈失效原因分析

Failure Analysis of Seal Ring of Seawater Butterfly Valve in Nuclear Power Plant

电厂维修人员在日常检修期间发现两台海水蝶阀密封不严,解体后发现其橡胶密封圈存在不同程度的撕裂。通过对失效橡胶密封圈及备件的宏观观察、材质鉴定、硬度测试、拉伸测试和压缩永久变形等分析手段,发现失效密封件为丁腈橡胶,橡胶本体已严重老化,对比新备件,拉伸性能和压缩永久变形各参数已下降,橡胶密封圈在阀门反复开关动作中受到挤压最终导致了开裂。

The maintenance personnel of the power plant found that the seals of the two seawater butterfly valves were not tight during daily maintenance.It found that their rubber seals were torn to varying degrees after disassembly.Through the macro observation,material identification,hardness test,tensile test and compression permanent deformation analysis of the failed rubber seal ring and spare parts,it was found that the failed seal was nitrile rubber,and the rubber body had been seriously aged.Compared with the new spare parts,the parameters of tensile properties and compression set had decreased.The rubber seal ring was squeezed during the repeated opening and closing action of the valve,which eventually led to cracking.