Method for nuclear power large-scale heat supply system to exit working condition when one main feed water pump trips

Abstract

The heat supply system pressurizes and heats the heat supply circulating water from the steam turbine high pressure cylinder exhaust pipe, and then supplies to the secondary heat exchange station. When the generator power is greater than 80.7%, the unit is in the reactor control mode, the steam turbine is in the LL control mode, the ICV is in the high exhaust pressure control mode, and the reactor thermal power is 100%. When the generator power is less than or equal to 80.7%, one main feed water pump trips. At this time, the steam turbine RB signal is triggered, and after a delay of 5s, the heat supply system exits the heat supply working condition, and after a delay of 5s, the heat supply system slowly exits, which can prevent the fluctuation of the unit load.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nuclear energy heating, in particular to a method for nuclear energy large-scale heating working condition under the condition of one main feed water pump tripping. BACKGROUND

[0002] Now cities have generally adopted central heating systems, and the heating energy is still mainly fossil energy, which is difficult to avoid the emission of carbon oxides affecting the environment. Nuclear energy as a clean, efficient and stable energy source can provide users with a continuous supply of heat, and nuclear energy heating is gradually becoming another energy supply type of nuclear energy. The existing nuclear power unit implements external heating, and after one main feed water pump trips under the heating working condition, the heating system is exited in the process of rapid power reduction of the steam turbine, and the influence of exiting the heating system on the unit needs to be considered. If the selection is not appropriate, the steam originally flowing to the heat exchanger will quickly enter the low-pressure cylinder of the steam turbine, which may affect the safe operation of the steam turbine. Therefore, the heating exit scheme after one feed water pump trips has important significance. SUMMARY

[0003] The present application provides a method for nuclear energy large-scale heating working condition under the condition of one main feed water pump tripping, which is used to solve the technical problem that during the external heating of the nuclear power heating unit, the large-scale heating steam quantity is large under the transient working condition of one feed water pump tripping, which accounts for more than 1 / 3 of the low-pressure cylinder steam inlet quantity, which may affect the strength of the low-pressure cylinder and cause the vibration of the steam turbine, thereby causing the shutdown and shutdown of the unit.

[0004] The technical scheme for solving the above technical problem is that the heating system pressurizes and heats the heat network circulating water from the steam turbine high-pressure cylinder exhaust pipe, and then supplies it to the secondary heat exchange station. When one main feed water pump trips, the heating system exits the heating working condition, which specifically includes the following steps: (1) one main feed water pump trips, triggering the RB signal of the steam turbine; (2) after a delay of 5s, triggering the heating system to exit the heating working condition.

[0005] After triggering the RB signal of the steam turbine, the steam turbine load decreases at a rate of 100% rated load / minute.

[0006] When the RB signal of the steam turbine is triggered for 18 seconds, the steam turbine load decreases to the target value.

[0007] When the RB signal of the steam turbine is triggered for 18 seconds, the GV opening is closed to the target opening.

[0008] When the steam turbine load is 70%, the heating system completely exits the heating working condition.

[0009] During the process of the steam turbine load decreasing within 0-18 seconds, the 4 ECVs are slowly closed.

[0010] When the generator power is less than or equal to 80.7%, one main feed water pump is tripped.

[0011] When the generator power is greater than 80.7%, the unit is in the mode of the reactor following the turbine control, and the turbine is in the mode of LL control.

[0012] The heat supply system comprises a steam side system for heat release and a circulating water side system for heat absorption. DETAILED DESCRIPTION

[0013] The present application provides a method for heat supply system to exit the working condition when one main feed water pump is tripped in the large-scale heat supply working condition of nuclear energy, the heat supply system pressurizes and heats the heat supply circulating water from the steam pipe of the high-pressure cylinder of the turbine, and then supplies the second heat exchange station, when the generator power is greater than 80.7%, the unit is in the mode of the reactor following the turbine control, and the turbine is in the mode of LL control, and the ICV is in the mode of high exhaust pressure control, and the reactor thermal power is 100%, when the generator power is less than or equal to 80.7%, one main feed water pump is tripped, at this time, the RB signal of the turbine is triggered, after 5s delay, the heat supply system exits the heat supply working condition, after 5s delay, the heat supply system slowly exits, which can prevent the fluctuation of the unit load, and has the technical effect of preventing the fluctuation of the unit load; after the RB signal of the turbine is triggered, the turbine load decreases at the rate of 100% rated load / minute, when the turbine load decreases to 70% at 18s, the GV opening is closed to the target opening, and the heat supply system completely exits the heat supply working condition. During the turbine load decreasing process within 0-18s, the four ECVs are slowly closed.

[0014] The heat supply system comprises a steam side system for heat release and a circulating water side system for heat absorption, and specifically comprises a heat supply circulating water system, a heat supply circulating water system and a heat supply circulating water system.

[0015] The English abbreviations used in the present application are RB=Run Back, the Chinese term is auxiliary fault load reduction, GV=Governing Valve, the Chinese term is high-pressure cylinder inlet steam regulating valve, ECV=Extraction steam control valve, the Chinese term is extraction steam regulating valve, and ICV=Intercept Valve, the Chinese term is low-pressure cylinder inlet steam regulating valve.

[0016] Although the embodiments of the present application have been shown and described above, it should be understood that the above-described embodiments are exemplary and should not be construed as limiting the present disclosure, and those skilled in the art can make changes, modifications and replacements to the above-described embodiments within the scope of the present disclosure.

Claims

1. A method for a nuclear energy large-scale heat supply system to exit a heat supply system operating condition when a main feedwater pump trips in a nuclear energy large-scale heat supply operating condition, characterized in that: The heating system pressurizes and heats the heat network circulating water from the exhaust pipe of the high-pressure cylinder of the steam turbine, and then supplies it to the secondary heat exchange station. When one main feed water pump trips, the heating system exits the heating working condition, which specifically includes the following steps: (1) One main feed water pump trips, triggering the RB signal of the steam turbine; (2) After a delay of 5s, the heating system exits the heating working condition; After the RB signal of the steam turbine is triggered in step (1), the load of the steam turbine decreases at a rate of 100% rated load per minute; When the RB signal of the steam turbine is triggered for 18s, the load of the steam turbine decreases to the target value; When the load of the steam turbine is 70%, the heating system completely exits the heating working condition; During the load decrease of the steam turbine in 0-18s, the 4 ECVs slowly close.

2. A method for a nuclear energy large scale heat supply system to exit from a heat supply condition in the case of a trip of a main feedwater pump according to claim 1, characterized in that: When the RB signal of the steam turbine is triggered for 18s, the GV opening is closed to the target opening.

3. A method of nuclear energy large scale heat supply system for heat supply condition in case of trip of a main feedwater pump according to claim 1, characterized in that: When the generator power is ≤80.7%, one main feed water pump trips.

4. A method for a nuclear energy large scale heat supply system to exit from a heat supply condition according to claim 3, wherein: When the generator power is >80.7%, the unit is in the stack following mode, and the steam turbine is in the LL control mode.

5. A method for a nuclear energy large scale heat supply system to exit from a heat supply condition in which a main feedwater pump is tripped according to any one of claims 1-2, characterized in that: The heating system includes a steam side system for releasing heat and a circulating water side system for absorbing heat.

6. A method of nuclear energy large scale heat supply system shutdown in case of trip of a main feedwater pump for heat supply conditions, according to claim 5, characterized in that: The heating system includes a heat network heating steam system, a heat network circulating water system and a heat network heater drain system.