Water inlet starting process for multi-module straight-flow evaporator of sodium-cooled fast reactor

Abstract

The invention particularly relates to a water inlet starting process for a multi-module straight-flow evaporator of a sodium-cooled fast reactor. The water inlet starting process comprises the following steps: step 101, positively heating the evaporator; step 102, reverse heating of the evaporator; 103, water is fed into the evaporator; the evaporator is arranged in a three-loop water vapor loop of the sodium-cooled fast reactor and consists of a plurality of evaporator modules. The method meets the requirement for on-site safe and stable operation of a sodium-cooled fast reactor unit, is suitable for water inlet starting control of the sodium-cooled fast reactor multi-module straight-flow evaporator, and fills the technical blank of water inlet of the sodium-cooled fast reactor multi-module straight-flow evaporator; the risks of sodium-water reaction and equipment damage in the water inlet process of the multi-module straight-flow evaporator of the sodium-cooled fast reactor are avoided.

Description

Technical Field

[0001] The invention relates to the technical field of sodium-cooled fast reactor direct-current steam generators, and in particular to a water-inlet start-up process for a sodium-cooled fast reactor multi-module direct-current evaporator. Background Art

[0002] Water inflow into the sodium-cooled fast reactor direct current steam generator is a key technology for the sodium-cooled fast reactor direct current steam generator and is a necessary condition for the sodium-cooled fast reactor to continue to increase its power after reaching the critical state. However, the multi-module direct current evaporator of the sodium-cooled fast reactor is a unique equipment for commercial sodium-cooled fast reactors, and there is no precedent for reference. In order to avoid the risk of sodium-water reaction and equipment damage during the water inflow of the multi-module direct current evaporator of the sodium-cooled fast reactor, it is necessary to develop a water inflow start-up technology for the multi-module direct current evaporator of the sodium-cooled fast reactor to fill the technical gap of water inflow into the multi-module direct current steam generator of the sodium-cooled fast reactor. Summary of the invention

[0003] The purpose of the present invention is to provide a water inlet startup process for a multi-module direct current evaporator of a sodium-cooled fast reactor, which is repeatedly verified during the startup process of a sodium-cooled fast reactor unit, meets the requirements for safe and stable on-site operation of the sodium-cooled fast reactor unit, is suitable for water inlet startup control of a multi-module direct current evaporator of a sodium-cooled fast reactor, fills the technical gap of water inlet for a multi-module direct current evaporator of a sodium-cooled fast reactor, and avoids the risks of sodium-water reaction and equipment damage during the water inlet process of a multi-module direct current evaporator of a sodium-cooled fast reactor.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] A sodium-cooled fast reactor multi-module direct-flow evaporator water inlet start-up process comprises the following steps:

[0006] Step 101, the evaporator is warm;

[0007] Step 102, evaporator reverse warming;

[0008] Step 103, water enters the evaporator;

[0009] The evaporator is in the third loop of the sodium-cooled fast reactor and is composed of a plurality of evaporator modules.

[0010] As one possible implementation method, step 101, the evaporator is warming up, includes the following steps:

[0011] The (185-190)℃ feed water in the deaerator is sent to the electric valve in front of the evaporator through the main feed water pump and the main feed water regulating valve, and the positive warming feed water is discharged to the sewage tank through the positive warming steam trap. During this process, the opening of the positive warming steam trap is manually controlled to make the temperature rise rate of the pipeline between the main feed water regulating valve and the electric valve in front of the evaporator at (3-5)℃ / min;

[0012] When the stem temperature of the positive heating steam trap reaches (150-160)℃, it means that the evaporator has completed positive heating.

[0013] As one of the achievable methods, step 101, the evaporator is warming up, specifically includes the following steps:

[0014] Step 1011, stop the main feed water pump, close the electric valve before the evaporator, the positive heating steam trap and the main feed water regulating valve;

[0015] Step 1012, operating the deaerator;

[0016] Step 1013, after the feed water temperature in the deaerator reaches (185-190)°C, operate the main feed water pump;

[0017] Step 1014, adjust the opening of the main water supply regulating valve to (5-15)%;

[0018] Step 1015, adjust the opening of the positive heating drain valve so that the temperature rise rate of the pipeline between the main feed water regulating valve and the electric valve before the evaporator is (3-5) ° C / min;

[0019] Step 1016, use a temperature gun to test the temperature of the positive heating steam trap valve stem. When the temperature of the positive heating steam trap valve stem reaches (150-160)°C, it indicates that the evaporator has completed positive heating.

[0020] Step 1017, shut down the deaerator and main feed water pump, and close the main feed water regulating valve and positive heating drain valve.

[0021] As one possible implementation method, step 102, evaporator reverse warming, includes the following steps:

[0022] The steam generated by the boiler is discharged to the blowdown tank after passing through the start-up expansion tank, the pressure reduction regulating valve, the start-up expansion module electric valve, the start-up expansion fast closing valve, the evaporator module and the anti-warming steam trap. During this process, the opening of the anti-warming steam trap is manually controlled to make the temperature rise rate of the pipeline between the start-up expansion tank and the anti-warming steam trap be (3-5)℃ / min;

[0023] When the difference between the inlet water supply pressure of the evaporator module and the pressure of the start-up expansion tank is (0~0.3)Mpa, and the inlet water supply temperature of the evaporator module is (185~190)℃ and is stable and no longer increases, it means that the evaporator has completed the reverse warming.

[0024] As one of the achievable methods, step 102, evaporator reverse warming, specifically includes the following steps:

[0025] Step 1021, close the opening and expansion quick closing valve;

[0026] Step 1022, operate the boiler and open the valve on the pipeline connecting the boiler and the start-up expansion vessel;

[0027] Step 1023, open the pressure reduction regulating valve and the start-up expansion module electric valve to preheat the pipeline between the start-up expansion container and the start-up expansion module electric valve;

[0028] Step 1024: After the pipeline pressure between the start-up expansion vessel and the start-up expansion module electric valve reaches (1-1.1) MPa, close the pressure reduction regulating valve;

[0029] Step 1025, open the expansion and opening fast closing valve to preheat the pipeline between the expansion and opening module electric valve and the anti-warming steam trap;

[0030] Step 1026, adjusting the opening of the step-down regulating valve to (3-5)%;

[0031] Step 1027, slightly open the anti-warming steam trap until there is a sound of airflow, and start the pipe between the expansion tank and the anti-warming steam trap to heat up at a rate of (3-5)°C / min;

[0032] Step 1028, operate the deaerator and the main feed water pump, open the main feed water regulating valve and the electric valve before the evaporator; when the difference between the feed water pressure at the inlet of the evaporator module and the pressure of the start-up expansion tank is (0-0.3) MPa, and the feed water temperature at the inlet of the evaporator module is (185-190)°C and is stable and no longer increases, it indicates that the evaporator has completed reverse warming;

[0033] Step 1029, shut down the boiler, deaerator and main feed water pump, close the valve on the pipe connecting the boiler and the start-up expansion tank, close the start-up expansion module electric valve, start-up expansion quick closing valve, pressure reduction regulating valve, anti-warming steam trap, main feed water regulating valve and electric valve before the evaporator.

[0034] As one possible implementation method, step 103, water entering the evaporator, includes the following steps:

[0035] The (185-190)℃ feed water in the deaerator enters the start-up expansion tank after passing through the main feed water pump, high-pressure heater, main feed water regulating valve, electric valve before evaporator, evaporator module, start-up expansion fast closing valve, start-up expansion module electric valve and pressure reduction regulating valve;

[0036] Maintain the sodium temperature at the outlet of the evaporator module at (245~250)℃ and complete water inflow to the evaporator.

[0037] As one possible implementation method, step 103, water is introduced into the evaporator, which specifically includes the following steps:

[0038] 1031. The evaporator module is put into large sodium water protection, the main feed water regulating valve opening is set to manual control, the power of the sodium-cooled fast reactor is maintained at (0.1-0.5)% × the full power of the sodium-cooled fast reactor, the step-down regulating valve is set to open automatic control after the pressure before the valve reaches 7MPa, and the speed of the main feed water pump is set to manual control;

[0039] 1032. Open the electric valve in front of the evaporator, the electric valve of the start-up and expansion module, the start-up and expansion quick-closing valve and the pressure-reducing regulating valve; operate the deaerator, the main feed water pump and the high-pressure heater;

[0040] 1033. When the water temperature in front of the main water supply regulating valve is (185-190)℃, adjust the opening of the main water supply regulating valve so that the water flow rate entering the evaporator module is (50-70)t / h, and the outlet water supply pressure of the evaporator module increases; when the outlet water supply pressure of the evaporator module rises to (3-4)MPa, and the water supply in the evaporator module becomes a water entity, reduce the opening of the main water supply regulating valve so that the outlet water supply pressure of the evaporator module increases at a rate of (0.3-0.6)MPa / min;

[0041] 1034. After the outlet water pressure of the evaporator module rises to 7MPa, increase the opening of the main water supply regulating valve to maintain the opening of the step-down regulating valve at (15-20)%;

[0042] 1035. Gradually increase the speed of the main water supply pump to maintain the pressure difference of the main water supply regulating valve at (0.8~1)MPa;

[0043] 1036. Change the speed of the main water supply pump from manual control to automatic control of the pressure difference of the main water supply regulating valve, and maintain the pressure difference of the main water supply regulating valve at (0.94~0.96)MPa;

[0044] 1037. By increasing the pressure setting value of the step-down regulating valve, the outlet water supply pressure of the evaporator module is gradually increased to 9.9 MPa;

[0045] 1038. Change the opening of the main feedwater regulating valve from manual control to automatic control of the sodium temperature at the outlet of the evaporator module, and maintain the sodium temperature at the outlet of the evaporator module at (245-250)°C;

[0046] 1039. The evaporator is filled with water.

[0047] As one of the achievable methods, the sodium-cooled fast reactor three-circuit includes a deaerator, a main feedwater pump, a high-pressure heater, an evaporator module, a superheater module, a main steam pipeline, a condenser, a boiler and a startup expansion tank; the deaerator is connected to the main feedwater pump pipeline, the main feedwater pump is connected to the evaporator module pipeline through the main feedwater regulating valve and the electric valve before the evaporator in turn, the main feedwater pump is connected to the high-pressure heater pipeline, the high-pressure heater is connected to the electric valve pipeline before the evaporator through the main feedwater regulating valve; the pipeline connecting the electric valve before the evaporator and the main feedwater regulating valve It is connected to the sewage tank pipeline through the positive heating steam trap, and the evaporator module is connected to the sewage tank pipeline through the reverse heating steam trap; the evaporator module is connected to the superheater module pipeline through the connecting valve, the evaporator module is connected to the main steam pipeline through the start-expansion quick-closing valve and the start-expansion module electric valve in turn, and the evaporator module is connected to the start-up expansion tank pipeline through the start-expansion quick-closing valve, the start-expansion module electric valve and the pressure reduction regulating valve in turn; the superheater module and the condenser are respectively connected to the main steam pipeline, and the boiler is respectively connected to the main steam pipeline and the start-up expansion tank through valve pipelines.

[0048] As one of the feasible ways, there are multiple main feed water pumps and high pressure heaters and they are arranged in parallel, there are multiple condensers, evaporator modules and superheater modules, one evaporator module is matched with one superheater module, multiple main feed water regulating valves in parallel, one evaporator front electric valve, one positive warming steam trap, one reverse warming steam trap, one connecting valve, one start-up and expansion quick closing valve, one start-up and expansion module electric valve and multiple parallel pressure reducing regulating valves; the deaerator is connected to the parallel main feed water pump pipelines, the parallel main feed water pumps are connected to the evaporator front electric valve pipeline matched with each evaporator module through the main feed water regulating valve matched with each evaporator module, and the evaporator front electric valve matched with each evaporator module is connected to the pipeline of each evaporator module; the pipeline connecting the evaporator front electric valve matched with each evaporator module and the main feed water regulating valve is connected through the matched positive The warm drain valve is connected to the sewage tank pipeline, and each evaporator module is connected to the sewage tank pipeline through a matching anti-warm drain valve; multiple parallel main feed water pumps are connected to multiple parallel high-pressure heater pipelines, and multiple parallel high-pressure heaters are respectively connected to the evaporator front electric valve pipeline matched by each evaporator module through the main feed water regulating valve matched by each evaporator module; each evaporator module is connected to the matching superheater module pipeline through a matching connecting valve, and each evaporator module is connected to the main steam pipeline through a matching start-expansion quick-closing valve and a start-expansion module electric valve in turn, and each evaporator module is connected to the start-up expansion tank pipeline through a matching start-expansion quick-closing valve, a start-expansion module electric valve and a pressure reduction regulating valve in turn; each superheater module and each condenser are respectively connected to the main steam pipeline, and the boiler is respectively connected to the main steam pipeline and the start-up expansion tank through valve pipelines.

[0049] Beneficial technical effects of the present invention:

[0050] The sodium-cooled fast reactor multi-module direct-current evaporator water inlet start-up process of the present invention clarifies the positive and reverse warming operation sequences and control parameters of the evaporator, ensuring that the evaporator heating rate meets the design requirements and satisfies the evaporator water inlet requirements; clarifies the evaporator water inlet operation sequence and control parameters, reduces the risk of equipment damage, and ensures that the evaporator water inlet is completed smoothly. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 The present invention is a flow chart of an embodiment of a water inlet startup process for a sodium-cooled fast reactor multi-module direct-flow evaporator. DETAILED DESCRIPTION

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0053] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0054] The technical solution of the present invention is clearly and completely described below in conjunction with the accompanying drawings and specific embodiments.

[0055] refer to Figure 1, shows a schematic diagram of the structure of an embodiment of a sodium-cooled fast reactor three-circuit, wherein the sodium-cooled fast reactor three-circuit includes a deaerator, a main feedwater pump, a high-pressure heater, an evaporator module, a superheater module, a main steam pipeline, a condenser, a boiler and a startup expansion tank; the deaerator is connected to the main feedwater pump pipeline, the main feedwater pump is connected to the evaporator module pipeline through the main feedwater regulating valve and the electric valve before the evaporator in turn, the main feedwater pump is connected to the high-pressure heater pipeline, the high-pressure heater is connected to the electric valve pipeline before the evaporator through the main feedwater regulating valve; the electric valve before the evaporator is connected to the main feedwater regulating valve The connected pipeline is connected to the sewage tank pipeline through the positive heating steam trap, and the evaporator module is connected to the sewage tank pipeline through the reverse heating steam trap; the evaporator module is connected to the superheater module pipeline through the connecting valve, and the evaporator module is connected to the main steam pipeline through the start-expansion quick-closing valve and the start-expansion module electric valve in turn, and the evaporator module is connected to the start-up expansion tank pipeline through the start-expansion quick-closing valve, the start-expansion module electric valve and the pressure reduction regulating valve in turn; the superheater module and the condenser are respectively connected to the main steam pipeline, and the boiler is respectively connected to the main steam pipeline and the start-up expansion tank through valve pipelines.

[0056] In this embodiment, as one of the feasible ways, there are multiple main feed water pumps and high pressure heaters and they are arranged in parallel, there are multiple condensers, evaporator modules and superheater modules, one evaporator module matches one superheater module, multiple main feed water regulating valves in parallel, one evaporator front electric valve, one positive warming steam trap, one reverse warming steam trap, one connecting valve, one start-up and expansion quick closing valve, one start-up and expansion module electric valve and multiple parallel pressure reducing regulating valves; the deaerator is connected to the parallel main feed water pump pipelines, the parallel main feed water pumps are respectively connected to the evaporator front electric valve pipeline matched with each evaporator module through the main feed water regulating valve matched with each evaporator module, and the evaporator front electric valve matched with each evaporator module is connected to the pipeline of each evaporator module; the pipeline connecting the evaporator front electric valve matched with each evaporator module and the main feed water regulating valve is connected through a matching The matched positive warming steam trap is connected to the sewage tank pipeline, and each evaporator module is connected to the sewage tank pipeline through the matched reverse warming steam trap; multiple parallel main feed water pumps are connected to multiple parallel high-pressure heater pipelines, and multiple parallel high-pressure heaters are respectively connected to the evaporator front electric valve pipeline matched by each evaporator module through the main feed water regulating valve matched by each evaporator module; each evaporator module is connected to the matched superheater module pipeline through the matched connecting valve, and each evaporator module is connected to the main steam pipeline through the matched start-expansion quick-closing valve and the start-expansion module electric valve in turn, and each evaporator module is connected to the start-up expansion tank pipeline through the matched start-expansion quick-closing valve, the start-expansion module electric valve and the pressure reduction regulating valve in turn; each superheater module and each condenser are respectively connected to the main steam pipeline, and the boiler is respectively connected to the main steam pipeline and the start-up expansion tank through valve pipelines.

[0057] This embodiment provides a sodium-cooled fast reactor multi-module direct-flow evaporator water inlet startup process, comprising the following steps:

[0058] Step 101, the evaporator is warm;

[0059] Step 102, evaporator reverse warming;

[0060] Step 103, water enters the evaporator;

[0061] The evaporator is in the third loop of the sodium-cooled fast reactor and is composed of a plurality of evaporator modules.

[0062] Before the evaporator enters the water, its outlet sodium temperature is maintained at (245-250)℃. In order to ensure that the temperature difference between the evaporator inlet feed water temperature and the evaporator outlet sodium temperature is less than 60℃ when the evaporator enters the water, so that the thermal shock meets the design requirements and the safety of the evaporator heat transfer tubes, the feed water temperature entering the evaporator must be (185-190)℃. In order to minimize the thermal shock of the pipes before and after the evaporator, the evaporator positive and reverse warming operations must be completed before the water enters the water.

[0063] In this embodiment, as one of the achievable methods, step 101, the evaporator is warming up, includes the following steps:

[0064] Step 1011, stop the main feed water pump, close the electric valve before the evaporator, the positive heating steam trap and the main feed water regulating valve;

[0065] Step 1012, operating the deaerator;

[0066] Step 1013, after the feed water temperature in the deaerator reaches (185-190)°C, operate the main feed water pump;

[0067] Step 1014, adjust the opening of the main water supply regulating valve to (5-15)%;

[0068] Step 1015, adjust the opening of the positive heating steam trap so that the temperature rise rate of the pipeline between the main feed water regulating valve and the electric valve before the evaporator is (3-5) °C / min;

[0069] Step 1016, use a temperature gun to test the temperature of the positive heating steam trap valve stem. When the temperature of the positive heating steam trap valve stem reaches (150-160)°C, it indicates that the evaporator has completed positive heating.

[0070] Step 1017, shut down the deaerator and main feed water pump, and close the main feed water regulating valve and positive heating drain valve.

[0071] In step 1013, the feed water temperature in the deaerator is the saturation temperature of the feed water in the deaerator under the heating steam source pressure, and the heating steam source pressure is (1.1-1.2) MPa.

[0072] In step 1014, the opening of the main water supply regulating valve is adjusted to (5-15)% so that the main water supply regulating valve has a certain pressure reducing effect, ensuring that the pressure behind the main water supply regulating valve is within the pressure range of the pipeline behind the positive heating steam trap, while meeting the positive heating water supply flow demand of the evaporator.

[0073] Step 1015, the temperature rise rate of the pipeline between the main feed water regulating valve and the electric valve before the evaporator is (3-5)°C / min to avoid thermal shock to the pipeline caused by sudden temperature changes.

[0074] In step 1016, when the valve stem temperature of the positive heating steam trap reaches (150-160)°C, it can ensure that the inner wall temperature of the pipeline is close to (185-190)°C, indicating that the evaporator has completed positive heating.

[0075] The process flow of positive heating of evaporator is as follows: the feed water of (185~190)℃ in the deaerator is sent to the electric valve in front of the evaporator through the main feed water pump and the main feed water regulating valve, and the positive heating feed water is discharged to the sewage tank through the positive heating steam trap. This process requires manual control of the opening of the positive heating steam trap so that the temperature rise rate of the pipeline between the main feed water regulating valve and the electric valve in front of the evaporator is between (3~5)℃ / min. The sign of completion of positive heating of evaporator is that the valve stem temperature of the positive heating steam trap reaches (150~160)℃.

[0076] In this embodiment, as one of the achievable methods, step 102, evaporator reverse warming, includes the following steps:

[0077] Step 1021, close the opening and expansion quick closing valve;

[0078] Step 1022, operate the boiler and open the valve on the pipeline connecting the boiler and the start-up expansion vessel;

[0079] Step 1023, open the pressure reduction regulating valve and the start-up expansion module electric valve to preheat the pipeline between the start-up expansion container and the start-up expansion module electric valve;

[0080] Step 1024: After the pipeline pressure between the start-up expansion vessel and the start-up expansion module electric valve reaches (1-1.1) MPa, close the pressure reduction regulating valve;

[0081] Step 1025, open the expansion and opening fast closing valve to preheat the pipeline between the expansion and opening module electric valve and the anti-warming steam trap;

[0082] Step 1026, adjusting the opening of the step-down regulating valve to (3-5)%;

[0083] Step 1027, slightly open the anti-warming steam trap until there is a sound of airflow, and start the pipe between the expansion tank and the anti-warming steam trap to heat up at a rate of (3-5)°C / min;

[0084] Step 1028, operate the deaerator and the main feed water pump, open the main feed water regulating valve and the electric valve before the evaporator; when the difference between the feed water pressure at the inlet of the evaporator module and the pressure of the start-up expansion tank is (0-0.3) MPa, and the feed water temperature at the inlet of the evaporator module is (185-190)°C and is stable and no longer increases, it indicates that the evaporator has completed reverse warming;

[0085] Step 1029, shut down the boiler, deaerator and main feed water pump, close the valve on the pipe connecting the boiler and the start-up expansion tank, close the start-up expansion module electric valve, start-up expansion quick closing valve, pressure reduction regulating valve, anti-warming steam trap, main feed water regulating valve and electric valve before the evaporator.

[0086] In step 1024, when the pipeline pressure between the start-up expansion vessel and the start-up expansion module electric valve reaches (1-1.1) MPa, the saturated air temperature in the corresponding pipeline is (185-190)°C.

[0087] In step 1025, the opening of the step-down regulating valve is adjusted to (3-5)% to ensure that the reverse warm steam source is met while avoiding pipeline steam hammer vibration.

[0088] The process flow of evaporator back-warming is as follows: the evaporator back-warming steam is taken from the boiler. The steam generated by the boiler enters the start-up expansion tank, the step-down regulating valve, the start-up expansion module electric valve, the start-up expansion fast closing valve, the evaporator module and the back-warming steam trap in turn, and then enters the sewage tank. The opening of the step-down regulating valve should not be too large. First, it prevents the sodium temperature at the outlet of the evaporator module from dropping too fast, which will introduce unexpected positive reactivity to the primary circuit, and second, it prevents the instantaneous excessive load of the boiler from causing the risk of boiler shutdown. The evaporator back-warming rate is controlled by the back-warming steam trap opening, which is (3~5)℃ / min. The sign of the completion of back-warming is that the difference between the inlet feed water pressure of the evaporator module and the start-up expansion tank pressure is (0~0.3)Mpa, and the inlet feed water temperature of the evaporator module is (185~190)℃ and is stable and no longer increases.

[0089] In this embodiment, as one of the achievable methods, step 103, water entering the evaporator, includes the following steps:

[0090] 1031. The evaporator module is put into large sodium water protection, the main feed water regulating valve opening is set to manual control, the power of the sodium-cooled fast reactor is maintained at (0.1-0.5)% × the full power of the sodium-cooled fast reactor, the step-down regulating valve is set to open automatic control after the pressure before the valve reaches 7MPa, and the speed of the main feed water pump is set to manual control;

[0091] 1032. Open the electric valve in front of the evaporator, the electric valve of the start-up and expansion module, the start-up and expansion quick-closing valve and the pressure-reducing regulating valve; operate the deaerator, the main feed water pump and the high-pressure heater;

[0092] 1033. When the water temperature in front of the main water supply regulating valve is (185-190)℃, adjust the opening of the main water supply regulating valve so that the water flow rate entering the evaporator module is (5-10)t / h and the water supply pressure at the outlet of the evaporator module increases; when the outlet pressure of the evaporator module rises to (3-4)MPa and the water supply in the evaporator module becomes a water entity, reduce the opening of the main water supply regulating valve so that the water supply pressure at the outlet of the evaporator module increases at a rate of (0.3-0.6)MPa / min;

[0093] 1034. After the outlet water pressure of the evaporator module rises to 7MPa, increase the opening of the main water supply regulating valve to maintain the opening of the step-down regulating valve at (15-20)%;

[0094] 1035. Gradually increase the speed of the main water supply pump to maintain the pressure difference of the main water supply regulating valve at (0.8~1)MPa;

[0095] 1036. Change the speed of the main water supply pump from manual control to automatic control of the pressure difference of the main water supply regulating valve, and maintain the pressure difference of the main water supply regulating valve at (0.94~0.96)MPa;

[0096] 1037. By increasing the pressure setting value of the step-down regulating valve, the outlet water supply pressure of the evaporator module is gradually increased to 9.9 MPa;

[0097] 1038. Change the opening of the main feedwater regulating valve from manual control to automatic control of the sodium temperature at the outlet of the evaporator module, and maintain the sodium temperature at the outlet of the evaporator module at (245-250)°C;

[0098] 1039. The evaporator is filled with water.

[0099] In step 1031, the outlet pressure of the main water supply pump at the lowest speed is 8MPa. Considering the resistance along the way and the pressure reduction effect after the main water supply regulating valve, and the pressure reduction effect before the pressure reduction regulating valve, the pressure before the pressure reduction regulating valve can reach up to 7MPa.

[0100] In step 1032, the water supply temperature before the main water supply regulating valve is (185-190)°C, and the sodium temperature at the outlet of the evaporator module is (245-250)°C, which can meet the requirement that the difference between the sodium temperature at the evaporator outlet and the water inlet temperature is less than 60°C.

[0101] In step 1033, the water supply flow rate entering the evaporator module is controlled by the change rate of the water supply pressure at the outlet of the evaporator module. If the water supply flow rate entering the evaporator module is too large, the water supply pressure at the outlet of the evaporator module will fluctuate greatly. If the water supply flow rate entering the evaporator module is too small, the evaporator module will be in a water vapor two-phase flow for a long time and the flow will be unstable. The increase rate of the water supply pressure at the outlet of the evaporator module is (0.3~0.6)MPa / min, so as to keep the change of the water supply pressure at the outlet of the evaporator module smooth.

[0102] In step 1034, the opening of the step-down regulating valve is maintained at (15-20)%, ensuring that the step-down regulating valve has a stable opening and will not open or close suddenly due to fluctuations in water flow or pressure.

[0103] The process flow of water inlet to the evaporator is:

[0104] The main feed water pump delivers the feed water at (185-190)°C in the deaerator through the high-pressure heater, the main feed water regulating valve and the electric valve before the evaporator into the evaporator module.

[0105] The feed water at (185-190)℃ in the evaporator module is heated and vaporized by liquid sodium at (245-250)℃. At the same time, since the step-down regulating valve will automatically open when the pressure before the valve is greater than 7MPa, the feed water continuously entering the evaporator module and the steam generated by heating are continuously compressed in a limited space, and the pressure continues to rise, causing the generated steam to be continuously compressed into water, and finally forming a saturated water entity with a temperature of (245-250)℃ and a pressure of (3-4)MPa in the evaporator module.

[0106] The feed water in the evaporator module undergoes the process of water-to-steam and steam-to-water, resulting in violent two-phase flow in the evaporator module. In order to shorten the impact time of the two-phase flow on the evaporator module, the opening of the main feed water regulating valve needs to be adjusted after the evaporator module enters the water, so that the outlet feed water pressure of the evaporator module is quickly increased to (3~4)MPa, so that the feed water in the evaporator module becomes a water entity.

[0107] After the outlet water supply pressure of the evaporator module rises to (3-4) MPa, the pressure inside the evaporator module rises rapidly because all the water supply inside the evaporator module becomes water entity. In order to control the pressure increase rate inside the evaporator and make the pressure inside the evaporator module rise smoothly, it is necessary to reduce the opening of the main water supply regulating valve to reduce the water supply flow entering the evaporator module.

[0108] After the outlet water supply pressure of the evaporator module rises to 7MPa, the pressure in front of the step-down regulating valve is greater than 7MPa, and the step-down regulating valve automatically opens. The saturated water entity formed in the evaporator module enters the start-up expansion tank through the start-up expansion quick-closing valve, the start-up expansion module electric valve and the step-down regulating valve. The opening of the step-down regulating valve automatically increases with the increase of the pressure in front of the valve. At this time, if the water supply flow entering the evaporator module is maintained unchanged, the evaporator module will be depressurized. After the evaporator module is depressurized, the pressure in front of the step-down regulating valve is lower than 7MPa, and the step-down regulating valve is automatically closed, resulting in an increase in the outlet water supply pressure of the evaporator module. This reciprocating process causes pressure fluctuations in the evaporator module. Therefore, at this time, it is necessary to increase the opening of the main water supply regulating valve to increase the water supply flow entering the evaporator module and maintain a stable opening of the step-down regulating valve.

[0109] Next, the speed of the main water supply pump can be gradually increased to maintain the pressure difference of the main water supply regulating valve at (0.8~1)MPa, and then the speed of the main water supply pump can be changed from manual control to automatic control of the water supply regulating valve pressure difference to maintain the water supply regulating valve pressure difference at (0.94~0.96)MPa.

[0110] Next, by increasing the pressure setting value of the step-down regulating valve, the outlet water supply pressure of the evaporator module is gradually increased to 9.9 MPa.

[0111] Finally, the opening of the main feed water regulating valve is changed from manual control to automatic control of the sodium temperature at the outlet of the evaporator module, maintaining the sodium temperature at the outlet of the evaporator module at (245-250)°C, and the evaporator completes water intake.

[0112] The evaporator completes water inflow, and the subsequent evaporator water supply is automatically adjusted as the power of the sodium-cooled fast reactor changes.

[0113] After the evaporator is filled with water, the three-circuit process flow of the sodium-cooled fast reactor is as follows: the main feed water pump sends the feed water at (185-190)℃ in the deaerator through the high-pressure heater, the main feed water regulating valve and the electric valve before the evaporator into the evaporator module. After the feed water in the evaporator module completes the heat exchange, it is reduced in pressure by the pressure reduction regulating valve and then discharged to the startup expansion tank. In the startup expansion tank, part of it is converted into steam and discharged to the high-pressure auxiliary steam header, and the feed water that has not been converted into steam is discharged to the condenser or deaerator.

[0114] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A sodium-cooled fast reactor multi-module direct-flow evaporator water inlet startup process, characterized in that: The steps include: Step 101, the evaporator is warm; Step 102, evaporator reverse warming; Step 103, water enters the evaporator; The evaporator is in the third loop of the sodium-cooled fast reactor and is composed of a plurality of evaporator modules.

2. The sodium-cooled fast reactor multi-module once-through evaporator water inlet startup process according to claim 1, characterized in that: Step 101, the evaporator is warming up, includes the following steps: The (185-190)℃ feed water in the deaerator is sent to the electric valve in front of the evaporator through the main feed water pump and the main feed water regulating valve, and the positive warming feed water is discharged to the sewage tank through the positive warming steam trap. During this process, the opening of the positive warming steam trap is manually controlled to make the temperature rise rate of the pipeline between the main feed water regulating valve and the electric valve in front of the evaporator at (3-5)℃ / min; When the stem temperature of the positive heating steam trap reaches (150-160)℃, it means that the evaporator has completed positive heating.

3. The sodium-cooled fast reactor multi-module once-through evaporator water inlet startup process according to claim 2, characterized in that: Step 101, the evaporator is warming up, specifically includes the following steps: Step 1011, stop the main feed water pump, close the electric valve before the evaporator, the positive heating steam trap and the main feed water regulating valve; Step 1012, operating the deaerator; Step 1013, after the feed water temperature in the deaerator reaches (185-190)°C, operate the main feed water pump; Step 1014, adjust the opening of the main water supply regulating valve to (5-15)%; Step 1015, adjust the opening of the positive heating drain valve so that the temperature rise rate of the pipeline between the main feed water regulating valve and the electric valve before the evaporator is (3-5) ° C / min; Step 1016, use a temperature gun to test the temperature of the positive heating steam trap valve stem. When the temperature of the positive heating steam trap valve stem reaches (150-160)°C, it indicates that the evaporator has completed positive heating. Step 1017, shut down the deaerator and main feed water pump, and close the main feed water regulating valve and positive heating drain valve.

4. The sodium-cooled fast reactor multi-module once-through evaporator water inlet startup process according to claim 1, characterized in that: Step 102, evaporator reverse warming, includes the following steps: The steam generated by the boiler is discharged to the blowdown tank after passing through the start-up expansion tank, the pressure reduction regulating valve, the start-up expansion module electric valve, the start-up expansion fast closing valve, the evaporator module and the anti-warming steam trap. During this process, the opening of the anti-warming steam trap is manually controlled to make the temperature rise rate of the pipeline between the start-up expansion tank and the anti-warming steam trap be (3-5)℃ / min; When the difference between the inlet water supply pressure of the evaporator module and the pressure of the start-up expansion tank is (0~0.3)Mpa, and the inlet water supply temperature of the evaporator module is (185~190)℃ and is stable and no longer increases, it means that the evaporator has completed the reverse warming.

5. The sodium-cooled fast reactor multi-module once-through evaporator water inlet startup process according to claim 4, characterized in that: Step 102, evaporator reverse warming, specifically includes the following steps: Step 1021, close the opening and expansion quick closing valve; Step 1022, operate the boiler and open the valve on the pipeline connecting the boiler and the start-up expansion vessel; Step 1023, open the pressure reduction regulating valve and the start-up expansion module electric valve to preheat the pipeline between the start-up expansion container and the start-up expansion module electric valve; Step 1024: After the pipeline pressure between the start-up expansion vessel and the start-up expansion module electric valve reaches (1-1.1) MPa, close the pressure reduction regulating valve; Step 1025, open the expansion and opening fast closing valve to preheat the pipeline between the expansion and opening module electric valve and the anti-warming steam trap; Step 1026, adjusting the opening of the step-down regulating valve to (3-5)%; Step 1027, slightly open the anti-warming steam trap until there is a sound of airflow, and start the pipe between the expansion tank and the anti-warming steam trap to heat up at a rate of (3-5)°C / min; Step 1028, operate the deaerator and the main feed water pump, open the main feed water regulating valve and the electric valve before the evaporator; when the difference between the feed water pressure at the inlet of the evaporator module and the pressure of the start-up expansion tank is (0-0.3) MPa, and the feed water temperature at the inlet of the evaporator module is (185-190)°C and is stable and no longer increases, it indicates that the evaporator has completed reverse warming; Step 1029, shut down the boiler, deaerator and main feed water pump, close the valve on the pipe connecting the boiler and the start-up expansion tank, close the start-up expansion module electric valve, start-up expansion quick closing valve, pressure reduction regulating valve, anti-warming steam trap, main feed water regulating valve and electric valve before the evaporator.

6. The sodium-cooled fast reactor multi-module once-through evaporator water inlet startup process according to claim 1, characterized in that: Step 103, water entering the evaporator, includes the following steps: The feed water (185-190) in the deaerator enters the start-up expansion tank after passing through the main feed water pump, high-pressure heater, main feed water regulating valve, electric valve before evaporator, evaporator module, start-up expansion fast closing valve, start-up expansion module electric valve and pressure reduction regulating valve; Maintain the sodium temperature at the outlet of the evaporator module at (245~250)℃ and complete water inflow to the evaporator.

7. The sodium-cooled fast reactor multi-module once-through evaporator water inlet startup process according to claim 6, characterized in that: Step 103, water entering the evaporator, specifically includes the following steps: 1031. The evaporator module is put into large sodium water protection, the main feed water regulating valve opening is set to manual control, the power of the sodium-cooled fast reactor is maintained at (0.1-0.5)% × the full power of the sodium-cooled fast reactor, the step-down regulating valve is set to open automatic control after the pressure before the valve reaches 7MPa, and the speed of the main feed water pump is set to manual control; 1032. Open the electric valve in front of the evaporator, the electric valve of the start-up and expansion module, the start-up and expansion quick-closing valve and the pressure-reducing regulating valve; operate the deaerator, the main feed water pump and the high-pressure heater; 1033. When the water temperature in front of the main water supply regulating valve is (185-190)℃, adjust the opening of the main water supply regulating valve so that the water flow rate entering the evaporator module is (50-70)t / h, and the outlet water supply pressure of the evaporator module increases; when the outlet water supply pressure of the evaporator module rises to (3-4)MPa, and the water supply in the evaporator module becomes a water entity, reduce the opening of the main water supply regulating valve so that the outlet water supply pressure of the evaporator module increases at a rate of (0.3-0.6)MPa / min; 1034. After the outlet water pressure of the evaporator module rises to 7MPa, increase the opening of the main water supply regulating valve to maintain the opening of the step-down regulating valve at (15-20)%; 1035. Gradually increase the speed of the main water supply pump to maintain the pressure difference of the main water supply regulating valve at (0.8~1)MPa; 1036. Change the speed of the main water supply pump from manual control to automatic control of the pressure difference of the main water supply regulating valve, and maintain the pressure difference of the main water supply regulating valve at (0.94~0.96)MPa; 1037. By increasing the pressure setting value of the step-down regulating valve, the outlet water supply pressure of the evaporator module is gradually increased to 9.9 MPa; 1038. Change the opening of the main feedwater regulating valve from manual control to automatic control of the sodium temperature at the outlet of the evaporator module, and maintain the sodium temperature at the outlet of the evaporator module at (245-250)°C; 1039. The evaporator is filled with water.

8. The sodium-cooled fast reactor multi-module once-through evaporator water inlet startup process according to claim 1, characterized in that: The sodium-cooled fast reactor three-circuit includes a deaerator, a main feedwater pump, a high-pressure heater, an evaporator module, a superheater module, a main steam pipeline, a condenser, a boiler and a startup expansion tank; the deaerator is connected to the main feedwater pump pipeline, the main feedwater pump is connected to the evaporator module pipeline through the main feedwater regulating valve and the electric valve before the evaporator in turn, the main feedwater pump is connected to the high-pressure heater pipeline, the high-pressure heater is connected to the electric valve pipeline before the evaporator through the main feedwater regulating valve; the pipeline connecting the electric valve before the evaporator and the main feedwater regulating valve is connected through the positive heating steam trap It is connected to the sewage tank pipeline, and the evaporator module is connected to the sewage tank pipeline through the anti-warming steam trap; the evaporator module is connected to the superheater module pipeline through the connecting valve, and the evaporator module is connected to the main steam pipeline through the start-expansion quick-closing valve and the start-expansion module electric valve in turn, and the evaporator module is connected to the start-up expansion tank pipeline through the start-expansion quick-closing valve, the start-expansion module electric valve and the pressure reduction regulating valve in turn; the superheater module and the condenser are respectively connected to the main steam pipeline, and the boiler is respectively connected to the main steam pipeline and the start-up expansion tank through valve pipelines.

9. The sodium-cooled fast reactor multi-module once-through evaporator water inlet startup process according to claim 8, characterized in that: There are multiple main feed water pumps and high-pressure heaters and they are arranged in parallel. There are multiple condensers, evaporator modules and superheater modules. One evaporator module is matched with one superheater module, multiple parallel main feed water regulating valves, an evaporator front electric valve, a positive heating steam trap, a reverse heating steam trap, a connecting valve, an expansion and opening quick closing valve, an expansion and opening module electric valve and multiple parallel pressure reduction regulating valves; the deaerator is connected to the parallel main feed water pump pipelines, and the parallel main feed water pumps are connected to the evaporator front electric valve pipeline matched with each evaporator module through the main feed water regulating valve matched with each evaporator module, and the evaporator front electric valve matched with each evaporator module is connected to each evaporator module pipeline; the pipeline connecting the evaporator front electric valve matched with each evaporator module and the main feed water regulating valve is connected to the sewage through the matched positive heating steam trap. The steam turbine is connected to the steam tank pipeline, and each evaporator module is connected to the sewage tank pipeline through a matching anti-warming steam trap; multiple parallel main feed water pumps are connected to multiple parallel high-pressure heater pipelines, and multiple parallel high-pressure heaters are respectively connected to the evaporator front electric valve pipeline matched by each evaporator module through the main feed water regulating valve matched by each evaporator module; each evaporator module is connected to the matching superheater module pipeline through a matching connecting valve, and each evaporator module is connected to the main steam pipeline through a matching start-expansion fast-closing valve and a start-expansion module electric valve in turn, and each evaporator module is connected to the start-up expansion tank pipeline through a matching start-expansion fast-closing valve, a start-expansion module electric valve and a pressure reduction regulating valve in turn; each superheater module and each condenser are respectively connected to the main steam pipeline, and the boiler is respectively connected to the main steam pipeline and the start-up expansion tank through valve pipelines.

Images