A steam-water recovery system for non-nuclear run-up of sodium-cooled fast reactor

Abstract

The invention discloses a steam-water recovery system for a non-nuclear run-up of a sodium-cooled fast reactor. The outlet of a once-through steam generator is connected to the inlet of a condenser and the inlet of a steam turbine. The exhaust port of the steam turbine is connected to the inlet of the condenser. The outlet of a desalted water plant is connected to the inlet of the condenser and the inlet of an auxiliary boiler. The outlet of the condenser is connected to the inlet of a condensate polishing system and the inlet of a turbine room waste liquid collection system via a condensate pump. The outlet of the condensate polishing system is connected to the inlet of the turbine room waste liquid collection system and the inlet of the auxiliary boiler. The outlet of the auxiliary boiler is connected to the inlet of an auxiliary steam header. The outlet of the auxiliary steam header is connected to the inlet of the steam turbine. The system can prevent condensate output by the condenser from being directly discharged into the turbine room waste liquid collection system.

Description

Technical Field

[0001] The invention belongs to the technical field of energy conservation and relates to a steam-water recovery system for non-nuclear impulse run of a sodium-cooled fast reactor. Background Art

[0002] Currently, there are two main schemes for non-nuclear start-up tests in nuclear power plants: (1) using the heat of the primary coolant pump and the electric heater of the pressurizer to generate steam for non-nuclear start-up; (2) setting up a commissioning boiler of sufficient capacity and using the commissioning boiler for non-nuclear start-up.

[0003] For large-capacity fast reactors, the thermal storage capacity of electric heaters and sodium coolant is generally insufficient to meet startup requirements. When using auxiliary boilers for non-nuclear startup, the original design involves producing demineralized water in the demineralized water plant and heating it in the auxiliary boiler to generate steam. Part of this steam is used to supply steam to the turbine shaft seals, while the remainder passes through the main steam header and into the turbine bypass line. This steam first flushes the piping before entering the turbine. Once the steam quality meets the requirements, the turbine inlet pressure is adjusted using the turbine bypass line. The steam then enters the turbine for startup. Exhaust steam is condensed into condensate in the condenser and discharged directly into the turbine room wastewater collection system, bypassing the condensate polishing system.

[0004] The disadvantages of the existing steam impulsion scheme are:

[0005] Waste of desalted water: In the existing solution, exhaust steam is condensed into condensate through the condenser, and is directly discharged into the waste liquid collection system of the steam turbine room without passing through the condensate polishing system, resulting in waste of desalted water.

[0006] Waste of boiler fuel: The condensate condensed from the condenser has a higher temperature than the desalted water produced in the desalted water plant. Directly discharging the condensate will also cause waste of high-enthalpy coolant, thereby increasing the waste of auxiliary boiler fuel and increasing the cost of non-nuclear run-up tests.

[0007] The desalinated water production system was under significant pressure: The original test plan required the desalinated water production system to operate continuously to provide a large amount of desalinated water for the non-nuclear run-up test. If the desalinated water production system could no longer provide sufficient desalinated water, the non-nuclear run-up test would have to be halted.

[0008] Non-nuclear power-up tests have poor disturbance resistance: This solution places high demands on the desalinated water system output and the stability of the auxiliary boiler fuel supply. If any external disturbance affects the test stability, the test will be forced to be terminated.

[0009] Impact of direct discharge of high-enthalpy coolant on site: High-enthalpy condensate has a significant impact on equipment and personnel, and also increases isolation processes and isolation measures. Summary of the Invention

[0010] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a steam-water recovery system for non-nuclear run-up of a sodium-cooled fast reactor, which can prevent the condensate output by the condenser from being directly discharged into the waste liquid collection system of the steam engine room.

[0011] To achieve the above-mentioned object, the steam-water recovery system for non-nuclear run-up of a sodium-cooled fast reactor of the present invention comprises a desalted water plant, an auxiliary boiler, an auxiliary steam header, a once-through steam generator, a steam turbine, a condenser, a condensate pump, a condensate polishing system and a turbine room waste liquid collection system;

[0012] The outlet of the once-through steam generator is connected to the inlet of the condenser and the inlet of the steam turbine, the exhaust port of the steam turbine is connected to the inlet of the condenser, the outlet of the desalted water plant is connected to the inlet of the condenser and the inlet of the auxiliary boiler, the outlet of the condenser is connected to the inlet of the condensate polishing system and the inlet of the turbine room waste liquid collection system through the condensate pump, the outlet of the condensate polishing system is connected to the inlet of the turbine room waste liquid collection system and the inlet of the auxiliary boiler, the outlet of the auxiliary boiler is connected to the inlet of the auxiliary steam header, and the outlet of the auxiliary steam header is connected to the inlet of the steam turbine.

[0013] The outlet of the desalted water plant is connected to the inlet of the auxiliary boiler, the outlet of the desalted water plant is connected to the inlet of the condenser, and the outlet of the condensate polishing system is connected to the inlet of the auxiliary boiler through the first pipeline.

[0014] The outlet of the auxiliary boiler is connected to the inlet of the auxiliary steam header via a second pipeline.

[0015] The outlet of the auxiliary steam header is connected to the inlet of the steam turbine through a third pipeline.

[0016] The outlet of the once-through steam generator is connected to the inlet of the condenser via a fourth pipeline.

[0017] The exhaust port of the steam turbine is connected to the inlet of the condenser through the fifth pipeline.

[0018] The outlet of the condenser is connected to the inlet of the condensate pump via the sixth pipeline.

[0019] The outlet of the condensate pump is connected to the inlet of the condensate polishing system through the seventh pipeline, and the outlet of the condensate pump is connected to the inlet of the steam turbine room waste liquid collection system through the eighth pipeline.

[0020] The outlet of the desalted water plant is connected to the inlet of the auxiliary boiler via the ninth pipeline, and the outlet of the desalted water plant is connected to the inlet of the condenser via the tenth pipeline.

[0021] The ninth pipeline is provided with a first stop valve and a first check valve, and the first pipeline is provided with a second stop valve and a second check valve.

[0022] The present invention has the following beneficial effects:

[0023] The steam-water recovery system for the non-nuclear start-up of a sodium-cooled fast reactor described in the present invention is configured to add a first pipeline during specific operation, wherein a pipeline between a condensate polishing system and a waste liquid collection system in a steam turbine room is connected to one end of the first pipeline, and the other end of the first pipeline is connected to a pipeline between a desalted water plant and an auxiliary boiler. A second stop valve and a second check valve are also configured to be added to the first pipeline. During operation, the condensate outputted from the condenser is treated by the condensate polishing system and then reintroduced into the auxiliary boiler, thereby reducing waste of desalted water and lowering the cost of auxiliary boiler fuel. In addition, when the auxiliary boiler needs to be replenished with water, it can be replenished with the condensate outputted from the condenser, thereby eliminating the need for the desalted water production system to continuously provide a large amount of desalted water, thereby greatly reducing the desalted water supply requirement for the desalted water production system during the non-nuclear start-up test and enhancing the anti-disturbance performance of the non-nuclear start-up test. At the same time, all high-enthalpy condensate discharged from the condenser is recovered, without having to consider the impact of the high-enthalpy condensate on equipment and personnel, thereby reducing unnecessary isolation processes and isolation measures. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the present invention.

[0025] Among them, 1 is the desalted water plant, 2 is the auxiliary boiler, 3 is the auxiliary steam header, 4 is the direct current steam generator, 5 is the steam turbine, 6 is the condenser, 7 is the condensate pump, 8 is the condensate polishing system, and 9 is the steam engine room waste liquid collection system. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only embodiments of a part of the present invention, not all embodiments, and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts disclosed in the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

[0027] The accompanying drawings illustrate schematic diagrams of the structures of the disclosed embodiments of the present invention. These figures are not drawn to scale; for the purpose of clarity, some details are exaggerated and some details may be omitted. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art may design regions / layers with different shapes, sizes, and relative positions as needed.

[0028] refer to Figure 1 The steam-water recovery system for the non-nuclear run-up of a sodium-cooled fast reactor of the present invention comprises a desalted water plant 1, an auxiliary boiler 2, an auxiliary steam header 3, a once-through steam generator 4, a steam turbine 5, a condenser 6, a condensate pump 7, a condensate polishing system 8, and a turbine room waste liquid collection system 9;

[0029] The outlet of the once-through steam generator 4 is connected to the inlet of the condenser 6 and the inlet of the steam turbine 5, the exhaust port of the steam turbine 5 is connected to the inlet of the condenser 6 via the fifth pipeline, the outlet of the desalted water plant 1 is connected to the inlet of the condenser 6 and the inlet of the auxiliary boiler 2, the outlet of the condenser 6 is connected to the inlet of the condensate polishing system 8 and the inlet of the turbine room waste liquid collection system 9 via the condensate pump 7, the outlet of the condensate polishing system 8 is connected to the inlet of the turbine room waste liquid collection system 9 and the inlet of the auxiliary boiler 2, the outlet of the auxiliary boiler 2 is connected to the inlet of the auxiliary steam header 3 via the second pipeline, and the outlet of the auxiliary steam header 3 is connected to the inlet of the steam turbine 5 via the third pipeline.

[0030] The outlet of the desalted water plant 1 is connected to the inlet of the auxiliary boiler 2 via the ninth pipeline, and the outlet of the desalted water plant 1 is connected to the inlet of the condenser 6 via the tenth pipeline. The ninth pipeline is provided with a first stop valve and a first check valve. The outlet of the condensate polishing system 8 is connected to the inlet of the auxiliary boiler 2 via the first pipeline. The first pipeline is provided with a second stop valve and a second check valve.

[0031] The outlet of the direct current steam generator 4 is connected to the inlet of the condenser 6 via the fourth pipeline, the outlet of the condenser 6 is connected to the inlet of the condensate pump 7 via the sixth pipeline, the outlet of the condensate pump 7 is connected to the inlet of the condensate polishing system 8 via the seventh pipeline, and the outlet of the condensate pump 7 is connected to the inlet of the steam turbine room waste liquid collection system 9 via the eighth pipeline.

[0032] The working process of the present invention is:

[0033] First stage (flushing stage)

[0034] Qualified desalted water enters the auxiliary boiler 2 through the ninth pipeline. The auxiliary boiler 2 uses the generated steam to flush the ninth pipeline, the second pipeline, the third pipeline and the fourth pipeline. At this time, the steam does not enter the steam turbine 5, but enters the condenser 6 through the fourth pipeline. The condenser 6 condenses the steam into condensate, and then enters the condensate polishing system 8 through the condensate pump 7 for treatment to produce qualified condensate, and then enters the auxiliary boiler 2 through the first pipeline. When the steam sampling of the main steam pipeline of the steam turbine is qualified, the flushing is completed. This stage lasts about 8-12 hours.

[0035] The second stage (steam parameter improvement stage)

[0036] When the steam quality is qualified, the turbine bypass valve is adjusted to increase the start-up steam parameters until the temperature and pressure reach the start-up parameters. This stage lasts about 0.5-1.5 hours.

[0037] The third stage (rush speed increase stage)

[0038] This stage lasts about 1-2 hours, and the specific process is: 1) Start-up stage (0-500rpm): Open the high-pressure main steam valve and regulating valve, increase the speed to 500rpm at a rate of 100rpm / min, and conduct a comprehensive inspection of the steam circuit at the 500rpm speed platform. No vibration or leakage occurs; 2) Warm-up stage (500-1400rpm): Increase the speed to 1400rpm at a rate of 100rpm / min, and warm up for 30 minutes; 3) High-speed warm-up stage (1400-2000rpm): Increase the speed to 2000rpm at a rate of 100rpm / min, check that there is no oscillation in the steam circuit, and start high-speed warm-up; 4) Rated speed operation stage (2000-3000rpm): Increase the speed to 3000rpm at a rate of 100rpm / min, and the maintenance time is generally not less than 2 hours.

[0039] The fourth stage (the stage of maintaining the speed during the impulse run)

[0040] The speed of the steam turbine 5 is increased to 3000 rpm and maintained for the impulse test. This stage lasts for about 2-4 hours according to the actual subsequent test requirements.

[0041] Taking the non-nuclear run-up test process of a sodium-cooled fast reactor steam turbine as an example: During the flushing phase, desalted water plant 1 produces desalted water. Qualified desalted water enters auxiliary boiler 2 via pipeline 9. Auxiliary boiler 2 heats the desalted water to the rated run-up parameters and then enters auxiliary steam header 3 via pipeline 2. Steam in auxiliary steam header 3 is split into two paths: one path serves as shaft seal steam, while the other path enters condenser 6 via pipelines 3 and 4. Condensate is condensed in condenser 6, then flows through pipeline 5 and condensate pump 7 to condensate polishing system 8. After treatment in condensate polishing system 8, the water enters auxiliary boiler 2 via pipeline 1. Once the circulation stabilizes, desalted water plant 1 no longer needs to supply desalted water to auxiliary boiler 2. Instead, a small amount of condenser make-up water is supplied to condenser 6 via pipeline 10 for normal operation. This phase lasts approximately 8-12 hours.

[0042] When the steam quality in the fourth pipeline is qualified, the steam is introduced into the steam turbine 5. The exhaust steam of the steam turbine 5 is pressurized by the condensate pump 7 and enters the condensate polishing system 8. Finally, it returns to the auxiliary boiler 2 through the first pipeline. This stage lasts about 0.5-1.5 hours.

[0043] When the steam temperature and pressure meet the start-up requirements, gradually increase the speed of the steam turbine 5 to 3000 rpm and maintain the speed for the start-up test. The steam-water circulation path remains unchanged. This stage lasts for about 2-4 hours.

[0044] The present invention has the following advantages:

[0045] 1) Fuel cost savings

[0046] Auxiliary boiler 2 is used for non-nuclear run-up. It heats desalted water at 20°C to steam with an outlet pressure of 2.1 MPa and a temperature of 280°C. After pipeline optimization, steam is condensed into condensate in condenser 6 and then passes through condensate polishing system 8 before entering auxiliary boiler 2 for heating. This requires only the fuel required to heat the desalted water from 20°C to 40°C. Based on steam generation at 95% of rated output (109 t / h) until the turbine non-nuclear run-up test is completed, with each test lasting 15.5 hours, each non-nuclear run-up test saves 3.395 tons of fuel. Based on the average market fuel price of 3,000 yuan / ton, this results in a cost savings of 10,185 yuan per non-nuclear run-up test.

[0047] 2) Savings in desalinated water costs

[0048] The existing technology does not recover desalted water during the entire test phase, resulting in a large waste of resources and costs. By optimizing the test steam-water loop, the amount of desalted water recovered by the system within the 15.5-h test time (109t / h) is the amount of desalted water saved by the optimized non-nuclear flushing test scheme.

[0049] Referring to other power plants, taking into account the costs of raw materials, fixed asset depreciation, labor, spare parts, instrument maintenance, drainage and other expenses, the cost of desalted water is set at 30 yuan / ton, which means that the cost of desalted water saved by a single flush is 50,685 yuan.

[0050] 3) Increased costs for branch pipes and valves

[0051] Based on the experience of similar projects, the cost of pipelines, valves and construction fees totals about 20,000 yuan. Taking into account the number of shutdowns for refueling and maintenance during the life of the sodium-cooled fast reactor, and assuming 30 non-nuclear impulse tests, a total cost saving of about 1.8 million yuan can be achieved.

Claims

1. A steam-water recovery system for non-nuclear run-up of a sodium-cooled fast reactor, characterized in that: It includes a desalted water plant (1), an auxiliary boiler (2), an auxiliary steam header (3), a once-through steam generator (4), a steam turbine (5), a condenser (6), a condensate pump (7), a condensate polishing system (8), and a turbine room waste liquid collection system (9); The outlet of the direct current steam generator (4) is connected to the inlet of the condenser (6) and the inlet of the steam turbine (5), the exhaust port of the steam turbine (5) is connected to the inlet of the condenser (6), the outlet of the desalted water plant (1) is connected to the inlet of the condenser (6) and the inlet of the auxiliary boiler (2), the outlet of the condenser (6) is connected to the inlet of the condensate polishing system (8) and the inlet of the turbine room waste liquid collection system (9) through the condensate pump (7), the outlet of the condensate polishing system (8) is connected to the inlet of the turbine room waste liquid collection system (9) and the inlet of the auxiliary boiler (2), the outlet of the auxiliary boiler (2) is connected to the inlet of the auxiliary steam header (3), and the outlet of the auxiliary steam header (3) is connected to the inlet of the steam turbine (5); The outlet of the desalted water plant (1) is connected to the inlet of the auxiliary boiler (2), the outlet of the desalted water plant (1) is connected to the inlet of the condenser (6), and the outlet of the condensate polishing system (8) is connected to the inlet of the auxiliary boiler (2) via a first pipeline; The outlet of the desalted water plant (1) is connected to the inlet of the auxiliary boiler (2) via a ninth pipeline, and the outlet of the desalted water plant (1) is connected to the inlet of the condenser (6) via a tenth pipeline; The ninth pipeline is provided with a first stop valve and a first check valve; A second stop valve and a second check valve are provided on the first pipeline.

2. The steam-water recovery system for non-nuclear run-up of a sodium-cooled fast reactor according to claim 1, characterized in that: The outlet of the auxiliary boiler (2) is connected to the inlet of the auxiliary steam header (3) via a second pipeline.

3. The steam-water recovery system for non-nuclear run-up of a sodium-cooled fast reactor according to claim 2, characterized in that: The outlet of the auxiliary steam header (3) is connected to the inlet of the steam turbine (5) via a third pipeline.

4. The steam-water recovery system for non-nuclear run-up of a sodium-cooled fast reactor according to claim 3, characterized in that: The outlet of the once-through steam generator (4) is connected to the inlet of the condenser (6) via a fourth pipeline.

5. The steam-water recovery system for non-nuclear run-up of a sodium-cooled fast reactor according to claim 4, characterized in that: The exhaust port of the steam turbine (5) is connected to the inlet of the condenser (6) via a fifth pipeline.

6. The steam-water recovery system for non-nuclear run-up of a sodium-cooled fast reactor according to claim 5, characterized in that: The outlet of the condenser (6) is connected to the inlet of the condensate pump (7) via a sixth pipeline.

7. The steam-water recovery system for non-nuclear run-up of a sodium-cooled fast reactor according to claim 6, characterized in that: The outlet of the condensate pump (7) is connected to the inlet of the condensate polishing system (8) via the seventh pipeline, and the outlet of the condensate pump (7) is connected to the inlet of the steam engine room waste liquid collection system (9) via the eighth pipeline.

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