Abstract: The model 100 reactor coolant pump is designed and manufactured by JSPM, which is widely used in the nuclear power plants all over the world. The No.1 seal housing flange is generally tightened by heat tightening bolts, the bolts are safe and reliable according to operation experience worldwide. According to nation’s nuclear power development strategy, the nuclear class fastening bolts have been made in China ,and used in domestic nuclear utilities widely. However, we are involved several seal housing bolts jamming recently. This paper analyzes and studies the reasons of the failure from the equipment structure, operation conditions and other factors,and develops a method to deal with the failure of the No.1 housing bolt jamming.The practice shows that the method can meet the emergency treatment requirements of the bolts jamming of model 100 reactor coolant pump No.1 seal housing.It provides useful feedback for maintenance of important equipment,cost saving and safe operation of nuclear utilities.