High temperature gas cooled reactor nuclear power unit secondary circuit starting and stopping system and method

Abstract

The invention discloses a high temperature gas cooled reactor nuclear power unit secondary circuit starting and stopping system and method. The system comprises a high-pressure cylinder, a low-pressure cylinder, sixteen valve groups, a steam-water separator, an evaporator, an external steam source, a bypass regulating valve, an auxiliary steam header, a high-pressure heater, a condenser, an auxiliary steam user, a unit drainage channel, a water feeding pump, a deaerator, a low-pressure heater, a condensation water pump, a condensation water supplementing system and a fine treatment system. Themethod comprises the following main steps that 1) steam is supplied by the external steam source to the auxiliary steam header in an initial stage of starting of a unit; 2) water in the steam-water separator is recovered to the deaerator; 3) bypass steam is recovered to the low-pressure heater, the auxiliary steam header and the high-pressure heater; 4) when steam extraction pressure of a steam turbine is sufficient, the steam turbine is used for extracting and supply the steam to the low-pressure heater, the auxiliary steam header and the high-pressure heater; and 5) in a secondary circuit stopping process, along with the decrease of a unit load, when the steam extraction pressure of the steam turbine is insufficient, steam in front of the bypass regulating valve is supplied to the low-pressure heater, the auxiliary steam header and the high-pressure heater.

Description

technical field [0001] The invention belongs to the technical field of nuclear power, and in particular relates to a system and a method for starting and stopping a secondary circuit of a high-temperature gas-cooled reactor nuclear power unit. Background technique [0002] In high temperature gas-cooled reactor nuclear power plants, the feed water at the evaporator inlet is heated by low-pressure heaters, deaerators, and high-pressure heaters to meet the water temperature requirements of the evaporator inlet. The normal steam sources for low-pressure heaters, deaerators, and high-pressure heaters are The steam extraction of the steam turbine; the main steam source of the auxiliary steam is the steam extraction of the steam turbine, and the backup steam source is the steam generated by the electric boiler; the water in the steam-water separator is discharged to the condenser after the water quality is qualified. [0003] The current system mainly has the following deficiencie...

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Problems solved by technology

[0004] 1) Before the steam turbine is under load, steam extraction cannot be obtained, and the feed water of the evaporator can only be heated by supplying steam to the deaerator through the start-up boiler. The start-up boiler needs to run for a long time, the cost is high, the heating effect is poor and unstable;

[0005] 2) At the initial stage of unit start-up, a large amount of steam is discharged to the condenser through the bypass, and the heat of the steam discharged into the condenser cannot be used, which is a waste of energy;

[0006] 3) The water in the steam-water separator has a certain temperature and pressure after the unit is started. After being discharged to the condenser, the heat of the water cannot be recovered and is all wasted.

[0007] 4) Steam and hot water are discharged into the condenser, which increases the temperature of the condensed water and reduces the efficiency of the steam turbine;

[0008] 5) If the temperature of condensed water is too high, it will affect the operation of fine treatment;

[0009] 6) After the steam enters the condenser and turns into condensed water, the condensed water pump must be used to pump it into the deaerator, which increases the power consumption of the condensed water pump;

[0010] 7) In the non-stop stacking operation condition, after the steam turbine is shut down, all the extraction steam is lost, the high-pressure heater, low-pressure heater, and deaerator steam source are all lost, and the temperature of the feed water at the evaporator inlet drops sharply, which affects the evaporator safety;

[0012] 9) During the normal operation of the unit, the electric boiler needs to be in a hot standby state, which is a waste of energy;

[0013] 10) Even if the electric boiler is in the hot standby state, it takes at least 15 minutes from the hot standby to the effective supply of steam to the auxiliary steam header. During the period when the auxiliary steam header loses the steam source, the deaerator loses heating. The shaft seal loses the steam source, which affects the safe operation and further start-up of the unit

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