A reactor loop and a loop structure of a low-temperature heating reactor having the reactor loop

Abstract

The present invention provides a reactor loop, the reactor loop includes a reactor vessel, a primary and secondary heat exchanger, a throttling device, a coolant storage tank, and a coolant pump, wherein the reactor vessel, the primary and secondary heat exchanger, the throttling device, the coolant storage tank, and the coolant pump are connected in sequence through pipelines. The present invention also provides a loop structure of a low-temperature heating reactor having the reactor loop. The loop structure of the low-temperature heating reactor of the present invention has low equipment cost; the loop is simple, and equipment including a stabilizer is eliminated; it has a high natural circulation capacity, can achieve high design safety and feasibility of conventional intervention under accidents, and achieve the integration of economy and safety.

Description

Technical Field

[0001] The invention relates to a reactor loop and a loop structure of a low-temperature heating reactor having the reactor loop. Background Art

[0002] Using nuclear reactors to provide urban central heating is one of the potential uses of nuclear energy. With the increasing environmental protection requirements, nuclear reactor heating projects without exhaust gas and greenhouse gas emissions have gradually been put on the agenda. Therefore, nuclear energy groups at home and abroad are competing to develop nuclear heating technology.

[0003] However, nuclear heating has its own technical requirements: 1) Its product is hot water at about 90°C, so the reactor loop is not required to operate at high temperature and high pressure. 2) In terms of economy, due to the competitive incentives in the heating market and the revenue window of only 4-6 months, nuclear heating projects require short cycles and low investment costs. 3) In terms of safety, since heating projects are close to residential areas and their products are in direct contact with people's production and life (unlike electricity), major reactor accidents are not allowed to occur, and radioactivity is not allowed to be released into the residential heating loop.

[0004] Based on the above requirements, the reactor loop structure of nuclear power plants currently used for power generation is not suitable for nuclear heating because it operates under high temperature and high pressure, the investment in the entire nuclear island equipment is expensive, and the construction period is very long.

[0005] Therefore, how to invent a reactor loop and a loop structure of a low-temperature heating reactor that are low in cost, simple in structure, have a high natural circulation capacity, and achieve both economical and safe integration has become an urgent problem to be solved. Summary of the invention

[0006] In view of the deficiencies of the prior art, the present invention proposes a reactor loop, characterized in that the reactor loop comprises a reactor vessel, a first- and second-loop heat exchanger, a throttling device, a coolant storage tank, and a coolant pump, wherein the reactor vessel, the first- and second-loop heat exchanger, the throttling device, the coolant storage tank, and the coolant pump are connected in sequence through pipelines.

[0007] Preferably, the primary and secondary circuit heat exchangers and the coolant storage tank are located above the top of the reactor vessel.

[0008] Preferably, the coolant in the coolant storage tank is pressurized under the drive of the coolant pump and flows into the reactor vessel through the coolant inlet pipe; it is heated by the nuclear fuel in the reactor vessel and then increases in temperature, flows through the coolant outlet pipe, passes through the first and second circuit heat exchangers, transfers heat to the intermediate circuit for cooling, and then flows into the throttling device, is depressurized to one atmosphere by the throttling device, and then flows into the coolant storage tank.

[0009] Preferably, the coolant storage tank is in communication with the atmosphere.

[0010] Preferably, the reactor loop further comprises a pressure relief pipeline, which connects the coolant outlet pipe and the coolant storage tank and is connected in parallel with the first and second loop heat exchangers and the throttling device.

[0011] Preferably, a normally closed regulating valve is provided on the pressure relief pipeline.

[0012] Preferably, the number of the coolant inlet pipe, the coolant pump, the coolant outlet pipe, the first and second circuit heat exchangers and the throttling device is more than two sets.

[0013] Preferably, a heat exchanger is provided in the coolant storage tank, and the heat exchanger is connected to an external cooling system through a pipeline.

[0014] Preferably, the reactor loop is also provided with a pit recirculation pipeline, which is connected to a pit located in a plant building where the reactor vessel is located, and then connected to a pump and connected to the coolant storage tank.

[0015] The present invention also provides a circuit structure of a low-temperature heating reactor, including an intermediate circuit and a user circuit, characterized in that the circuit structure also includes a reactor circuit as described in any one of claims 1 to 9, and heat is transferred in sequence between the reactor circuit, the intermediate circuit and the user circuit through a heat exchanger.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The loop structure of the low-temperature heating reactor designed by the present invention has low equipment cost because the loop is a low-pressure design; since the equipment loop is simple and equipment including a stabilizer is eliminated, the investment cost of the entire reactor loop is low; the loop has a high natural circulation capacity, and because of the low-pressure design, it is only equipped with a simple safety system, which can achieve high design safety and the feasibility of conventional intervention under accidents, thereby realizing the integration of economy and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the circuit structure of the low temperature heating reactor of the present invention, wherein:

[0019] 1-reactor vessel, 2-primary and secondary circuit heat exchangers, 3-throttling device, 4-coolant storage tank, 5-cooling machine pump, 6-coolant outlet pipe, 7-coolant inlet pipe, 8-pressure relief pipeline, 9-normally closed regulating valve, 10-heat exchanger in coolant storage tank, 11-pit. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] like Figure 1 As shown, a circuit structure of a low-temperature heating reactor of the present invention includes three circuits: a reactor circuit, an intermediate circuit, and a user circuit. Heat is transferred in sequence between the circuits through heat exchangers.

[0022] The working circuit of the above reactor circuit in normal operation is composed of a reactor vessel 1, a primary and secondary circuit heat exchanger 2, a throttling device 3, a coolant storage tank 4, and a coolant pump 5, which are connected in sequence through pipelines. The coolant in the coolant storage tank 4 is pressurized under the drive of the coolant pump 5 and flows into the reactor vessel 1 through the coolant inlet pipe; after being heated by the nuclear fuel in the reactor vessel, the temperature is increased, and the coolant passes through the coolant outlet pipe, flows through the primary and secondary circuit heat exchanger 2, transfers the heat to the intermediate circuit, cools down, flows into the throttling device 3, and is depressurized to one atmosphere through the throttling device, and then flows into the coolant storage tank 4. It can be seen from the normal working mode of the circuit that the above reactor circuit operates in a low-pressure and low-temperature state compared with the traditional commercial reactor and eliminates the device of the pressurizer.

[0023] Preferably, the one- and two-loop heat exchangers 2 and the coolant storage tank 4 are located above the top of the reactor vessel, forming a certain height difference with the reactor vessel. Such an arrangement is mainly to form the ability of natural circulation and gravity injection. When a non-pipeline rupture accident occurs, if the coolant pump is unavailable, the coolant is cooled by the one- and two-loop heat exchangers or the heat exchanger in the coolant storage tank from above, forming a natural circulation between the pipeline, the reactor vessel, and the coolant storage tank, and continuously taking out the heat of the reactor. When a pipeline rupture accident occurs, although the pressure in the reactor vessel will be slightly higher in the early stage, the coolant in the coolant storage tank will soon be continuously injected into the reactor vessel through the coolant inlet pipe through the height difference, submerging the fuel assembly in the reactor vessel.

[0024] Preferably, the coolant storage tank is connected to the atmosphere and is at normal pressure. In addition to making the entire circuit in a low-pressure state close to atmospheric pressure, this design also facilitates coolant operation during normal operation and safe operation under accidents. During normal operation, the boric acid concentration in the coolant needs to be adjusted with the operating time, and the coolant also needs to be sampled. This operation on the coolant during normal operation can be completed by connecting a storage tank at normal pressure (even directly in the storage tank), without having to connect high-pressure pipelines and high-pressure pumps like commercial nuclear power plants. In addition, when an accident occurs, the coolant storage tank assumes the function of a heat sink and a cooling water source. Designing it to be at normal pressure facilitates human intervention in the operation, such as continuously injecting water from a pit or other sources into the storage tank in a simple manner.

[0025] Preferably, the reactor loop is also provided with a pressure relief pipeline, which connects the coolant outlet pipe and the coolant storage tank, and is structurally connected in parallel with the primary and secondary circuit heat exchangers and the throttling device. This pressure relief pipeline is used to form a natural circulation loop in non-breach accidents, and is used to relieve pressure on the reactor vessel in breach accidents. After all, the primary and secondary circuit heat exchangers and the throttling device have large flow resistance, so it is necessary to set up a parallel loop to reduce the loop resistance of the natural circulation, and when necessary, directly inject the saturated water vapor in the reactor vessel into the coolant storage tank to relieve pressure on the reactor vessel.

[0026] Preferably, a normally closed regulating valve is provided on the pressure relief pipeline. During normal operation, the valve is normally closed. Only after an accident occurs, the valve or valve group is opened to form a natural circulation loop or to relieve pressure on the reactor vessel.

[0027] Preferably, there are at least two sets of coolant inlet pipes and coolant pumps, and at least two sets of coolant outlet pipes, first- and second-circuit heat exchangers, and throttling devices. Multiple circuits are set up, on the one hand, due to the limitation of equipment capacity, especially the first- and second-circuit heat exchangers; on the other hand, when a problem occurs in one of the circuits, the other circuits can be used to alleviate the accident.

[0028] Preferably, a heat exchanger is provided in the coolant storage tank, and the heat exchanger is connected to an external cooling system through a pipeline. The coolant storage tank is used as a heat sink and an injection water tank in the event of an accident, so the heat of the water in it must be continuously removed and the volume of the water must be continuously replenished. The task of removing heat and replenishing water requires the access of an external system. Since the coolant storage tank is at normal pressure, removing heat from the coolant storage tank and replenishing water to it only requires a relatively simple external system.

[0029] Preferably, the reactor loop is also provided with a pit recirculation pipeline, which is connected to the pit located in the plant where the reactor vessel is located, and then connected to the coolant storage tank after being connected to the pump. When a breach accident occurs, the coolant sprayed or gushed out from the reactor vessel will gradually gather in the pit. In particular, after a long period of time after the accident, the reactor vessel is also in a normal pressure state, and then the water of the reactor vessel is continuously injected from the coolant storage tank. After cooling the fuel assembly, it will gush out from the breach into the pit. At this time, the water in the pit is pumped into the coolant storage tank through the pit circulation pipeline, so that the recycling of the pit water can be realized and the amount of radioactive wastewater generated can be reduced.

[0030] Preferably, the coolant storage tank is provided with an external injection interface for access to an external system.

[0031] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0032] Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementation should not be considered as exceeding the scope of the present invention.

[0033] Obviously, those skilled in the art can make various changes and modifications to the invention without departing from the spirit and scope of the invention. Thus, if these modifications and variations of the invention fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.

Claims

1. A reactor loop, characterized in that: The reactor loop includes a reactor vessel, a primary and secondary loop heat exchanger, a throttling device, a coolant storage tank, and a coolant pump. The reactor vessel, the primary and secondary circuit heat exchangers, the throttling device, the coolant storage tank and the coolant pump are connected in sequence through pipelines.

2. The reactor loop according to claim 1, characterized in that The primary and secondary circuit heat exchangers and the coolant storage tank are located above the top of the reactor vessel.

3. The reactor loop according to claim 1, characterized in that The coolant in the coolant storage tank is pressurized under the drive of the coolant pump and flows into the reactor vessel through the coolant inlet pipe; it is heated by the nuclear fuel in the reactor vessel and then increases in temperature, flows through the coolant outlet pipe, passes through the first and second circuit heat exchanger, transfers the heat to the intermediate circuit for cooling, and then flows into the throttling device, is depressurized to one atmosphere through the throttling device, and then flows into the coolant storage tank.

4. The reactor loop according to claim 1, characterized in that The coolant storage tank is in communication with the atmosphere.

5. The reactor loop according to claim 1, characterized in that The reactor loop also includes a pressure relief pipeline, which is connected to the coolant outlet pipe and the coolant storage tank and is connected in parallel with the first and second loop heat exchangers and the throttling device.

6. The reactor loop according to claim 5, characterized in that A normally closed regulating valve is arranged on the pressure relief pipeline.

7. The reactor loop according to claim 5, characterized in that The number of the coolant inlet pipe, the coolant pump, the coolant outlet pipe, the first and second circuit heat exchangers and the throttling device is more than two sets.

8. The reactor loop according to claim 1, characterized in that A heat exchanger is arranged in the coolant storage tank, and the heat exchanger is connected to an external cooling system through a pipeline.

9. The reactor loop according to claim 1, characterized in that The reactor loop is also provided with a pit recirculation pipeline, which is connected to the pit located in the plant where the reactor vessel is located, and then connected to the coolant storage tank after being connected to a pump.

10. A circuit structure of a low temperature heating reactor, comprising an intermediate circuit and a user circuit, characterized in that: The circuit structure also includes a reactor circuit as claimed in any one of claims 1 to 9, wherein heat is transferred in sequence between the reactor circuit, the intermediate circuit and the user circuit via a heat exchanger.

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