Isobaric reactor starting and stopping system of high-temperature gas cooled reactor unit

Abstract

The utility model provides an isobaric reactor start-stop system of a high-temperature gas cooled reactor unit, which comprises a nuclear island evaporator, a steam-water separator, a bypass drain valve, a steam-water separator drain valve and a condenser, the nuclear island evaporator is connected to a main steam collecting pipe through a first main steam pipeline and a second main steam pipeline, and the reactor start-stop system is connected to the main steam collecting pipe through a first main steam pipeline and a second main steam pipeline. The pressure of an outlet of the nuclear island evaporator is maintained at a rated value through the bypass drain valve, the liquid level in the steam-water separator is maintained within a rated range through the steam-water separator drain valve, and compared with the prior art, the device has the advantages that a reactor starting and stopping system is simplified, and the manufacturing cost is saved; active control targets are reduced, and operation control logic is clear and concise; a steam-water separator inlet regulating valve is omitted, so that the operation stability is improved, and the operation intensity is reduced; a steam-water separator safety valve is omitted, and part fault hidden dangers are reduced.

Description

Technical Field

[0001] The system of the utility model belongs to the thermal system within the scope of the conventional island of the high-temperature gas-cooled reactor nuclear power unit, and is applicable to the start-up and shutdown system of the high-temperature gas-cooled reactor nuclear power unit. This technology can achieve remarkable effects in aspects such as simplifying the existing start-up and shutdown system of the high-temperature gas-cooled reactor nuclear power unit, simplifying operation control, improving system reliability, and saving construction investment. Background Art

[0002] The high-temperature gas-cooled reactor unit is equipped with an independent start-up and shutdown system. During the start-up and shutdown process of the high-temperature gas-cooled reactor nuclear island, the start-up and shutdown system establishes the start-up cycle of the secondary side of the nuclear island, protects the nuclear island evaporator, and takes away the heat generated by the nuclear island during the start-up and shutdown process.

[0003] The existing start-up and shutdown of the in-operation high-temperature gas-cooled reactor unit is a pressure-reducing system. The key components configured in the start-up and shutdown system include a steam-water separator, a steam-water separator inlet regulating valve, a bypass discharge valve, and a steam-water separator drain valve.

[0004] The designed operating pressure of the steam-water separator in the pressure-reducing start-up and shutdown system is lower than the designed operating pressure at the outlet of the nuclear island evaporator. During the commissioning stage of the start-up and shutdown system, the steam-water separator inlet regulating valve is used to maintain the constant value of the pressure at the outlet of the nuclear island evaporator at 13.9 MPa(a) or 14.3 MPa(a), and the bypass discharge valve and the steam-water separator drain valve are used to maintain the constant value of the operating pressure of the steam-water separator at 5.0 MPa(a). The operating conditions of the steam-water separator inlet regulating valve in the existing start-up and shutdown system are complex, the selection is difficult, the equipment cost is expensive, and the operation control logic is complex. Summary of the Utility Model

[0005] The purpose of the utility model is to develop a start-up and shutdown system scheme for a high-temperature gas-cooled reactor unit with isobaric operation, so as to cancel the pressure-reducing link in the start-up and shutdown process of the high-temperature gas-cooled reactor unit, simplify the system configuration, optimize the operation control, reduce potential accident hazards, and reduce the operation intensity on the premise of ensuring the system functions.

[0006] To achieve the above object, the utility model provides an isobaric start-up and shut-down reactor system for a high-temperature gas-cooled reactor unit, which includes a nuclear island evaporator, a steam-water separator, a bypass discharge valve, a steam-water separator drain valve and a condenser. The nuclear island evaporator is connected to the main steam header through a first main steam pipeline and a second main steam pipeline. The nuclear island evaporator, the first main steam pipeline, the third main steam pipeline, the steam-water separator inlet pipeline and the steam-water separator are connected in sequence. The upper outlet and the lower outlet of the steam-water separator are respectively connected to the inlet steam pipeline of the bypass discharge valve and the inlet pipeline of the steam-water separator drain valve through the steam-water separator outlet pipeline. The bypass discharge valve is connected to the upper inlet of the condenser through the bypass discharge valve outlet steam pipeline. The steam-water separator drain valve is connected to the lower inlet of the condenser through the steam-water separator drain valve outlet pipeline. A steam-water separator bypass pipeline is arranged between the steam-water separator inlet pipeline and the steam-water separator outlet pipeline. The nuclear island evaporator, the first main steam pipeline, the third main steam pipeline, the steam-water separator bypass pipeline, the inlet steam pipeline of the bypass discharge valve, the bypass discharge valve, the bypass discharge valve outlet steam pipeline and the condenser are connected in sequence. Valves are respectively arranged on the first main steam pipeline, the second main steam pipeline, the steam-water separator bypass pipeline, the steam-water separator inlet pipeline and the steam-water separator outlet pipeline.

[0007] During the start-up and shut-down operation stage of the reactor system, the bypass discharge valve is used to maintain the outlet pressure of the nuclear island evaporator at the rated value, and the steam-water separator drain valve is used to maintain the liquid level in the steam-water separator within the rated range. Compared with the prior art, the utility model has the following advantages: the start-up and shut-down reactor system is simplified, saving the construction cost; the number of active control targets is reduced, and the operation control logic is clear and concise; the inlet regulating valve of the steam-water separator is cancelled, improving the operation stability and reducing the operation intensity; the safety valve of the steam-water separator is cancelled, reducing the potential trouble of component failure. Brief Description of the Drawings

[0008] Appendix Figure 1 It is a system diagram of the solution of the utility model.

[0009] The marks in the drawings are as follows: 1 - nuclear island evaporator; 2 - condenser; 3 - steam-water separator; 4 - bypass discharge valve; 5 - steam-water separator drain valve; 6 - first main steam pipeline; 7 - second main steam pipeline; 8 - third main steam pipeline; 9 - steam-water separator inlet pipeline; 10 - steam-water separator outlet pipeline; 11 - steam-water separator bypass pipeline; 12 - inlet steam pipeline of the bypass discharge valve; 13 - bypass discharge valve outlet steam pipeline; 14 - inlet pipeline of the steam-water separator drain valve; 15 - steam-water separator drain valve outlet pipeline. Detailed Embodiment

[0010] The utility model provides an isobaric start-up and shut-down reactor system for a high-temperature gas-cooled reactor unit. The designed operating pressure of the steam-water separator 3 in the isobaric start-up and shut-down reactor system is equal to the designed operating pressure of the nuclear island evaporator 1. The operating pressure before the bypass discharge valve 4 and the steam-water separator drain valve 5 is equal to the outlet pressure of the nuclear island evaporator 1. Compared with the step-down start-up and shut-down reactor system, the isobaric start-up and shut-down reactor system cancels the regulating valve at the inlet of the steam-water separator and the safety valve of the steam-water separator. The key components of the isobaric start-up and shut-down reactor system are composed of an isobaric steam-water separator 3, a bypass discharge valve 4, and a steam-water separator drain valve 5.

[0011] The system includes a nuclear island evaporator 1, a steam-water separator 3, a bypass discharge valve 4, a steam-water separator drain valve 5, and a condenser 2. The nuclear island evaporator 1 is connected to the main steam header through a first main steam pipeline 6 and a second main steam pipeline 7. The nuclear island evaporator 1, the first main steam pipeline 6, a third main steam pipeline 8, a steam-water separator inlet pipeline 9, and the steam-water separator 3 are connected in sequence. The upper outlet and the lower outlet of the steam-water separator 3 are respectively connected to the bypass discharge valve inlet steam pipeline 12 and the steam-water separator drain valve inlet pipeline 14 through a steam-water separator outlet pipeline 10. The bypass discharge valve 4 is connected to the upper inlet of the condenser 2 through a bypass discharge valve outlet steam pipeline 13. The steam-water separator drain valve 5 is connected to the lower inlet of the condenser 2 through a steam-water separator drain valve outlet pipeline 15. A steam-water separator bypass pipeline 11 is arranged between the steam-water separator inlet pipeline 9 and the steam-water separator outlet pipeline 10. The nuclear island evaporator 1, the first main steam pipeline 6, the third main steam pipeline 8, the steam-water separator bypass pipeline 11, the bypass discharge valve inlet steam pipeline 12, the bypass discharge valve 4, the bypass discharge valve outlet steam pipeline 13, and the condenser 2 are connected in sequence. Valves are respectively arranged on the first main steam pipeline 6, the second main steam pipeline 8, the steam-water separator bypass pipeline 11, the steam-water separator inlet pipeline 9, and the steam-water separator outlet pipeline 12.

[0012] The main process of this system is designed according to Appendix Figure 1 for design.

[0013] The operation process of the isobaric start-up reactor system is divided into four stages:

[0014] Stage 1: The outlet of the nuclear island evaporator 1 is in the subcooled water stage

[0015] The valve (LBA10 AA101), the valve (LBH10 AA101), and the steam-water separator drain valve 5 are in the open state; the valve (LBA10 AA102), the valve (LBF10 AA101), the valve (LBH20 AA101), and the bypass discharge valve 4 are in the closed state.

[0016] Starting from the reactor startup, the temperature of the medium at the outlet of the nuclear island evaporator 1 gradually rises from ~105°C to ~338.3°C, with a pressure of 14.3 MPa(a). The outlet medium is subcooled water, and the subcooled water enters the steam separator 3 through the first main steam pipe 6, the third main steam pipe 8, and the steam-water separator inlet pipe 9. The inside of the steam separator 3 is a liquid phase space, and the subcooled water is controlled and discharged to the condenser 2 through the steam separator drain valve 5.

[0017] The feed water pump at the front end of the nuclear island evaporator 1 controls the circulation flow rate, and the steam separator drain valve 5 controls the set value of the outlet pressure of the nuclear island evaporator 1.

[0018] Phase 2: The outlet of the nuclear island evaporator 1 is in the wet steam stage

[0019] Valve (LBA10 AA101), Valve (LBH10 AA101), Valve (LBH20 AA101), steam separator drain valve 5, and bypass discharge valve 4 are in the open state; Valve (LBA10 AA102) and Valve (LBF10 AA101) are in the closed state.

[0020] The temperature of the medium at the outlet of the nuclear island evaporator 1 is ~338.3°C, with a pressure of 14.3 MPa(a). The outlet medium is wet steam, and the wet steam enters the steam separator 3 through the first main steam pipe 6, the third main steam pipe 8, and the steam-water separator inlet pipe 9. The steam separator 3 separates the steam and water from the wet steam, and the saturated steam is controlled and discharged to the condenser 2 through the steam separator outlet pipe 10, the bypass discharge valve inlet steam pipe 12, the bypass discharge valve 4, and the bypass discharge valve outlet steam pipe 13. The saturated water is controlled and discharged to the condenser 2 through the steam separator drain valve inlet pipe 14, the steam separator drain valve 5, and the steam separator drain valve outlet pipe 15.

[0021] The feed water pump at the front end of the nuclear island evaporator 1 controls the circulation flow rate, the bypass discharge valve 4 controls the set value of the outlet pressure of the nuclear island evaporator; the steam separator drain valve 5 controls the liquid level inside the steam separator.

[0022] Phase 3: The outlet of the nuclear island evaporator 1 is in the superheated steam stage I

[0023] Valve (LBA10 AA101), Valve (LBH10 AA101), Valve (LBH20 AA101), and bypass discharge valve 4 are in the open state; Valve (LBA10 AA102), Valve (LBF10 AA101), and steam separator drain valve 5 are in the closed state.

[0024] The temperature of the medium at the outlet of the nuclear island evaporator is between ~338.3°C and ~370°C, the pressure is 14.3 MPa(a), and the outlet medium is superheated steam. The superheated steam enters the steam separator 3 through the first main steam pipeline 6, the third main steam pipeline 8 and the steam-water separator inlet pipeline 9, and then is discharged to the condenser 2 through the steam-water separator outlet pipeline 10, the bypass discharge valve inlet steam pipeline 12, the bypass discharge valve 4 and the bypass discharge valve outlet steam pipeline 13 in a controlled manner.

[0025] The front-end feed water pump of the nuclear island evaporator 1 controls the circulation flow rate, and the bypass discharge valve 4 controls the set value of the outlet pressure of the nuclear island evaporator 1; the steam-water separator drain valve 5 is interlocked and closed.

[0026] Stage 4: The outlet of the nuclear island evaporator is in the superheated steam stage II

[0027] The valve (LBA10 AA101), the valve (LBF10 AA101), and the bypass discharge valve 4 are in the open state; the valve (LBA10 AA102), the valve (LBH10 AA101), the valve (LBH20 AA101), and the steam-water separator drain valve 5 are in the closed state.

[0028] The temperature of the medium at the outlet of the nuclear island evaporator 1 is between ~370°C and the rated main steam temperature, the pressure is 14.3 MPa(a), and the outlet medium is superheated steam. All the superheated steam is discharged to the condenser 2 through the first main steam pipeline 6, the third main steam pipeline 8, the steam-water separator bypass pipeline 11, the bypass discharge valve inlet steam pipeline 12, the bypass discharge valve 4, and the bypass discharge valve outlet steam pipeline 13 in a controlled manner.

[0029] The front-end feed water pump of the nuclear island evaporator 1 controls the circulation flow rate, the bypass discharge valve 4 controls the set value of the outlet pressure of the nuclear island evaporator, the steam-water separator 3 is taken out of operation, and the steam-water separator drain valve 5 is interlocked and closed.

Claims

1. A high-temperature gas-cooled reactor unit isobaric start-up and shutdown system, characterized in that: It includes a nuclear island evaporator, a steam-water separator, a bypass discharge valve, a steam-water separator trap and a condenser. The nuclear island evaporator is connected to the main steam header through the first main steam pipeline and the second main steam pipeline. The nuclear island evaporator, the first main steam pipeline, the third main steam pipeline, the steam-water separator inlet pipeline and the steam-water separator are connected in sequence. The upper outlet and the lower outlet of the steam-water separator are connected to the bypass discharge valve inlet steam pipeline and the steam-water separator trap inlet pipeline respectively through the steam-water separator outlet pipeline. The bypass discharge valve is connected to the upper inlet of the condenser through the bypass discharge valve outlet steam pipeline. The steam-water separator trap is connected to the lower inlet of the condenser through the steam-water separator trap outlet pipe, a steam-water separator bypass pipe is arranged between the steam-water separator inlet pipe and the steam-water separator outlet pipe, the nuclear island evaporator, the first main steam pipe, the third main steam pipe, the steam-water separator bypass pipe, the bypass discharge valve inlet steam pipe, the bypass discharge valve, the bypass discharge valve outlet steam pipe and the condenser are connected in sequence, and valves are respectively arranged on the first main steam pipe, the second main steam pipe, the steam-water separator bypass pipe, the steam-water separator inlet pipe and the steam-water separator outlet pipe.

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