System and method for extreme hot start of high temperature gas cooled reactor nuclear power unit

Abstract

The invention discloses a system and method for extreme hot start of a high temperature gas cooled reactor nuclear power unit. The system comprises a steam turbine, an evaporator, a primary loop system, a steam-water separator, a high-pressure heater, a deaerator, a water supply pump and seven valve groups. The method comprises the following main steps that factors for triggering reactor protection are analyzed, the protection factors that helium circulation of the primary loop system and feed-water circulation of the secondary loop evaporator do not need to be terminated after reactor protection actions are identified, and circulation of the primary loop system and the secondary loop system is maintained after the reactor protection actions; in the re-start process of the reactor unit, steam and water are recycled, and the water is conveyed through the steam-water separator into the deaerator so as to increase the feed-water temperature; before impulse starting of the steam turbine, the steam generated by the evaporator is introduced into the high-pressure heater so as to further increase the feed-water temperature. According to the method, the time from shutdown to re-start of the high temperature gas cooled reactor nuclear power unit is reduced to 3 hours or below from 170 hours or above, and the availability of the high temperature gas cooled reactor nuclear power unit is greatly improved.

Description

technical field [0001] The invention belongs to the technical field of nuclear power, and in particular relates to a system and method for starting a high-temperature gas-cooled reactor nuclear power unit in an extremely hot state. Background technique [0002] At present, for high-temperature gas-cooled reactor nuclear power units, after the reactor trips, the main nuclear fan stops, the inlet and outlet baffles of the main nuclear fan are closed, and the inlet water valve and outlet steam valve on the secondary side of the evaporator are closed, interrupting the primary and secondary loop circulation. ; The steam source of the low-pressure heater, deaerator and high-pressure heater is all interrupted, and the feed water cannot be heated. [0003] The current system mainly has the following deficiencies: [0004] 1) After the reactor trips, even if the cause of the unit trip is judged in a short time and the trip factor is eliminated, it can be started immediately, but the...

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Problems solved by technology

[0004] 1) After the reactor trips, even if the cause of the unit trip is judged in a short time and the trip factor is eliminated, it can be started immediately, but the current design must cool the evaporator and the reactor in order to re-establish the primary loop cycle and the secondary loop cycle, and this process It takes more than 170 hours, reducing the availability of high temperature gas-cooled reactor nuclear power units;

[0005] 2) The cooling of the evaporator needs to go through pressure relief and emptying, the process control is complicated, the cooling rate is not easy to control, and the weld seam of the evaporator is prone to cracks, which threatens the safety of the evaporator;

[0006] 3) After the secondary side of the evaporator is depressurized and emptied, the pressure on the secondary side is much lower than the pressure on the primary side, and the evaporator generates reverse pressure, which deviates from the normal operating conditions of the evaporator (normal operation secondary side 14Mpa, primary side 7Mpa, After pressure relief and emptying, the secondary side pressure is lower than 1Mpa, while the primary side pressure is maintained at 7MPa), which is easy to cause damage to the evaporator;

[0007] 4) During the cooling process of the evaporator using auxiliary steam, water hammer is prone to occur, which is not conducive to the safe operation of the evaporator;

[0008] 5) After the evaporator is cooled, when the cycle is established again, the temperature of the feed water is difficult to increase due to the limited heating source of the feed water temperature, and the temperature of the primary side of the evaporator is very high (especially at the initial stage of starting the main nuclear fan), causing the evaporator The temperature difference between the primary side and the secondary side is very large, and the evaporator is easily damaged

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