Nuclear power plant steam generator blowdown system and flow regulating valve anti-cavitation method thereof

Abstract

The invention discloses a nuclear power plant steam generator blowdown system and a flow regulating valve anti-cavitation method thereof. The blowdown system comprises a blowdown pipeline, a heat exchanger, a flow regulating valve, a flowmeter, a filtering and desalting purification unit and a condenser, wherein the blowdown pipeline is connected between a steam generator and the condenser; the heat exchanger, the flow regulating valve, the flowmeter and the filtering and desalting purification unit are arranged on the blowdown pipeline. According to the anti-cavitation method, a throttling element is arranged on the blowdown pipeline between the flow regulating valve and the condenser, so that the pressure of a downstream outlet of the flow regulating valve is improved, and the pressure drop of the flow regulating valve is reduced to eliminate the influence on valve cavitation. Compared with the prior art, the nuclear power plant steam generator blowdown system has the advantage that the pressure of the downstream outlet of the flow regulating valve is improved through the throttling element additionally arranged on the nuclear power plant steam generator blowdown system disclosed by the invention, so that the flow regulating valve does not need to work under a cavitation working condition, and the service life is prolonged.

Description

technical field [0001] The invention belongs to the field of nuclear power. More specifically, the invention relates to a blowdown system of a steam generator of a nuclear power plant and a method for preventing cavitation of a flow regulating valve thereof. Background technique [0002] see figure 1 , in the pressurized water reactor nuclear power plant unit, the main function of the steam generator blowdown system is to maintain the water quality of the secondary side by continuously blowing down the secondary side of the steam generator 10. During normal operation, the sewage on the secondary side of the steam generator 10 is continuously discharged at a certain flow rate, and the sewage is cooled by exchanging heat with the cooling water system 13 through the non-regenerative / regenerative heat exchanger 12 , and then filtered through the desalination purification unit 14 It is discharged to the condenser 16 and returned to the secondary loop water circulation system. T...

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Problems solved by technology

On the other hand, the sewage flow rate of the steam generator sewage system is usually only 1% of the rated steam flow rate. The flow regulating valve 18 has been working under the condition of high pressure difference and low flow rate for a long time. The high pressure drop makes the valve very prone to cavitation. thereby seriously affecting its service life

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