Main pump shaft seal water injection system of a nuclear power station

A main pump shaft seal water injection system of a nuclear power plant, comprising:

• a jet pump, a high pressure cooler, a hydrocyclone, valves and a main connection pipeline arranged outside of a main pump, an auxiliary pump and an internal flow path arranged in the main pump, inner and outer flow paths of the main pump are connected with a shaft seal water injection hole and a high temperature water drainage hole on the main connection pipeline, the main connection pipeline is connected between an upper filling water pipeline of a RCV and a shaft seal water injection hole of a main flange, the jet pump, the high pressure cooler and the hydrocyclone are sequentially arranged on the main connection pipeline, further comprising a bypass pipeline connected in parallel with the jet pump, the high pressure cooler and the hydrocyclone, the main connection pipeline is provided with a normally open main pipeline isolating valve at each end of a parallel section connected in parallel with the bypass pipeline, the bypass pipeline allows low temperature upper filling water in the RCV system to bypass the jet pump, the high pressure cooler and the hydrocyclone, and enter the shaft seal water injection hole of the main flange directly.