阅读说明：本技术 百万千瓦级核电厂乏燃料转运容器的循环冷却方法 (Circulation cooling method for spent fuel transfer container of million-kilowatt nuclear power plant ) 是由 徐万年 张文利 魏学舟 张库国 郑崇枫 刘省勇 王哲 于 2019-08-30 设计创作，主要内容包括：本发明属于百万千瓦级核电站乏燃料处理技术领域,尤其涉及一种百万千瓦级核电厂乏燃料转运容器的循环冷却方法,本发明的百万千瓦级核电厂乏燃料转运容器的循环冷却方法,通过先对乏燃料转运容器的内腔内充压缩气体,直至该内腔内的放射性到预设放射值；再在乏燃料转运容器内充除盐水,除盐水可有效避免因乏燃料转运容器的内腔内的温度过高导致的硼酸结晶,再通过硼水对乏燃料转运容器内充硼水,并持续充硼水循环冷却,使得内腔的稳定到达预设温度,以方便后续卸料拆除外盖等一系列操作。(The invention belongs to the technical field of spent fuel treatment of million kilowatt nuclear power stations, and particularly relates to a circulating cooling method of a spent fuel transfer container of a million kilowatt nuclear power station, which comprises the steps of filling compressed gas into an inner cavity of the spent fuel transfer container until radioactivity in the inner cavity reaches a preset radioactivity value; and then the spent fuel transfer container is filled with demineralized water, the demineralized water can effectively avoid boric acid crystallization caused by overhigh temperature in the inner cavity of the spent fuel transfer container, then the spent fuel transfer container is filled with boron water through the boron water, and the boron water is continuously filled for circulating cooling, so that the inner cavity stably reaches the preset temperature, and a series of operations such as subsequent unloading, outer cover removal and the like are facilitated.)

1. A circulation cooling method of a spent fuel transfer container of a million kilowatt nuclear power plant is used for cooling the spent fuel transfer container, and is characterized in that: the method comprises the following steps:

setting a preset radiation value and a preset temperature for the inner cavity of the spent fuel transfer container;

filling compressed gas into the inner cavity until the radiation value of the inner cavity reaches the preset radiation value;

filling the inner cavity with demineralized water, and then filling the inner cavity with boric water;

continuously cooling the boron-filled water in the inner cavity in a circulating manner to reduce the temperature of the inner cavity to the preset temperature;

and discharging all the boron water in the inner cavity.

2. The method for circularly cooling the spent fuel transfer container in the million kilowatt nuclear power plant according to claim 1, characterized in that: in the step of filling the inner cavity with compressed gas, a compressed air device communicated with the spent fuel transfer container is provided, the compressed air device continuously blows air to the spent fuel transfer container for more than 30min, and the air pressure is 0.2 MPa.

3. The method for circularly cooling the spent fuel transfer container in the million kilowatt nuclear power plant according to claim 1, characterized in that: and providing a discharging cooling device communicated with the spent fuel transferring container and the compressed air device respectively, wherein the discharging cooling device can transmit wind of the compressed air device to the spent fuel transferring container.

4. The method for circularly cooling the spent fuel transfer container in the million kilowatt nuclear power plant according to claim 3, characterized in that: and providing a shielding and filtering device communicated with the spent fuel transfer container and used for filtering the gas discharged from the spent fuel transfer container, wherein the tail end of the shielding and filtering device is provided with a detection structure for detecting the radioactivity of the discharged gas.

5. The method for circularly cooling the spent fuel transfer container in the million kilowatt nuclear power plant according to claim 4, is characterized in that: the specific steps of filling the spent fuel transfer container with demineralized water are as follows: injecting 1m into the spent fuel transfer container³And the flow rate of the desalted water is 2m³/h。

6. The method for circularly cooling the spent fuel transfer container in the million kilowatt nuclear power plant according to claim 5, characterized in that: the step of filling the transport container with boric water comprises the following specific steps: continuously injecting boron water into the spent fuel transfer container, wherein the flow rate is 5.6m³/h。

7. The method for circularly cooling the spent fuel transfer container in the million kilowatt nuclear power plant according to claim 6, characterized in that: the provided canning pool is provided, the canning pool is internally provided with the boron water, spent fuel is transported the container discharge the boron water is arranged to the canning pool.

8. The method for circularly cooling the spent fuel transfer container in the million kilowatt nuclear power plant according to claim 7, characterized in that: the circulating cooling of the spent fuel transfer container is specifically as follows: and providing a high-flow submersible pump, circularly stirring the canning pool through the high-flow submersible pump, and continuously injecting the boron water at the bottom of the canning pool into the spent fuel transfer container.

9. The method for circularly cooling the spent fuel transfer container in the million kilowatt nuclear power plant according to claim 8, characterized in that: the continuous injection of the boron water at the bottom of the canning pool into the spent fuel transfer container is specifically as follows: detect the temperature of the delivery port department of container is transported to spent fuel, if the temperature of delivery port is greater than 35 ℃ to pause the cooling when being less than 40 ℃ the container is transported to spent fuel, and opens through the torque wrench the inner cup bolt of container is transported to spent fuel, if can open, stops the cooling.

10. The method for circularly cooling the spent fuel transfer container in the million kilowatt nuclear power plant according to claim 9, characterized in that: the continuous injection of the boron water at the bottom of the canning pool into the spent fuel transfer container is specifically as follows: detect the temperature of the delivery port department of container is transported to spent fuel, if the temperature of delivery port is greater than 40 ℃, or is greater than 35 ℃ and be less than 40 ℃ but can't open during the inner cup bolt, to 2m are poured into in the container is transported to spent fuel³And (4) cooling by continuously supplementing the boric water, and stopping cooling when the water temperature at the water outlet is 35 ℃.

Technical Field

The invention belongs to the technical field of spent fuel treatment of million-kilowatt nuclear power stations, and particularly relates to a circulating cooling method for a spent fuel transfer container of a million-kilowatt nuclear power station.

Background

Spent fuel is a nuclear fuel that has been irradiated with radiation and used, and is produced by a nuclear reactor in a nuclear power plant. Nuclear fuel after nuclear reactor reactions contains a large amount of radioactive elements and therefore has a large amount of radioactivity, which, if not properly disposed of, can seriously affect the environment and the health of the personnel in contact with them. Along with the service time of the nuclear power unit is prolonged, the spent fuel assemblies generated by operation are accumulated year by year and approach to reach the design capacity of a spent fuel pool, and the spent fuel is transported out of the spent fuel pool by considering the use of a transport container. After the spent fuel transportation container is filled, helium is required to be filled into the container to establish thermal balance between a spent fuel assembly cladding and a cavity, the maximum temperature of a spent fuel assembly in the transportation container reaches 273 ℃, the average temperature of helium in the cavity is about 200 ℃ and the temperature of a container shell exceeds 85 ℃ after the spent fuel is fully loaded to reach a thermal balance state. Before the unloading operation, the inner cavity of the container needs to be filled with water and exhausted, and cooling circulation is carried out simultaneously, so that the temperature of the outer surface of the spent fuel transport container is lower than 35 ℃, and a series of operations such as unloading and outer cover removal are facilitated.

Disclosure of Invention

The invention aims to provide a circulating cooling method for a spent fuel transfer container of a million-kilowatt nuclear power plant, and aims to solve the technical problem that spent fuel in the prior art needs to be cooled so as to facilitate discharging and outer cover removal.

In order to achieve the purpose, the invention adopts the technical scheme that: a circulation cooling method for a spent fuel transfer container of a million kilowatt nuclear power plant is used for cooling the spent fuel transfer container and comprises the following steps:

setting a preset radiation value and a preset temperature for the inner cavity of the spent fuel transfer container;

filling compressed gas into the inner cavity until the radiation value of the inner cavity reaches the preset radiation value;

filling the inner cavity with demineralized water, and then filling the inner cavity with boric water;

continuously cooling the boron-filled water in the inner cavity in a circulating manner to reduce the temperature of the inner cavity to the preset temperature;

and discharging all the boron water in the inner cavity.

Further, in the step of filling the inner cavity with compressed gas, a compressed air device communicated with the spent fuel transfer container is provided, the compressed air device continuously blows air to the spent fuel transfer container for more than 30min, and the air pressure is 0.2 MPa.

Further, a discharge cooling device is provided which is respectively communicated with the spent fuel transfer container and the compressed air device, and the discharge cooling device can transmit wind of the compressed air device to the spent fuel transfer container.

Further, a shielding and filtering device which is communicated with the spent fuel transferring container and is used for filtering the gas discharged from the spent fuel transferring container is provided, and the tail end of the shielding and filtering device is provided with a detection structure for detecting the radioactivity of the discharged gas.

Further, the filling of the demineralized water into the spent fuel transfer container specifically comprises: injecting 1m into the spent fuel transfer container³And the flow rate of the desalted water is 2m³/h。

Further, the filling of the boric water into the transfer container specifically comprises: continuously injecting boron water into the spent fuel transfer container, wherein the flow rate is 5.6m³/h。

Further, a canning pool is provided, the inside of the canning pool is provided with the boron water, the spent fuel is transported the container and is discharged the boron water is arranged extremely in the canning pool.

Further, the circulating cooling of the spent fuel transfer container specifically comprises: and providing a high-flow submersible pump, circularly stirring the canning pool through the high-flow submersible pump, and continuously injecting the boron water at the bottom of the canning pool into the spent fuel transfer container.

Further, the continuously injecting the boron water at the bottom of the canning pool into the spent fuel transfer container specifically comprises: detect the temperature of the delivery port department of container is transported to spent fuel, if the temperature of delivery port is greater than 35 ℃ to pause the cooling when being less than 40 ℃ the container is transported to spent fuel, and opens through the torque wrench the inner cup bolt of container is transported to spent fuel, if can open, stops the cooling.

Further, the continuously injecting the boron water at the bottom of the canning pool into the spent fuel transfer container specifically comprises: detect the temperature of the delivery port department of container is transported to spent fuel, if the temperature of delivery port is greater than 40 ℃, or is greater than 35 ℃ and be less than 40 ℃ but can't open during the inner cup bolt, to 2m are poured into in the container is transported to spent fuel³Cooling with ice and continuously supplementing the boron water whenAnd when the water temperature at the water outlet is 35 ℃, stopping cooling.

The invention has the beneficial effects that: the invention relates to a circulating cooling method of a spent fuel transfer container of a million kilowatt nuclear power plant, which comprises the steps of filling compressed gas into an inner cavity of the spent fuel transfer container until the radioactivity in the inner cavity reaches a preset radioactivity value; and then the spent fuel transfer container is filled with demineralized water, the demineralized water can effectively avoid boric acid crystallization caused by overhigh temperature in the inner cavity of the spent fuel transfer container, then the spent fuel transfer container is filled with boron water through the boron water, and the boron water is continuously filled for circulating cooling, so that the inner cavity stably reaches the preset temperature, and a series of operations such as subsequent unloading, outer cover removal and the like are facilitated.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

Fig. 1 is a schematic flow chart of a method for circularly cooling a spent fuel transfer container of a million kilowatt nuclear power plant according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a circulation cooling method for a spent fuel transfer container of a million kilowatt nuclear power plant according to an embodiment of the present invention.

Wherein, in the figures, the respective reference numerals:

10-spent fuel transfer vessel; 20-a discharge cooling device;

30-a shielded filter device; and 40, an ice storage pool.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to fig. 1-2 are exemplary and intended to be illustrative of the invention and should not be construed as limiting the invention.

In the description of the present invention, it is to be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships illustrated in the drawings, and are used merely for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

As shown in fig. 1 to 2, an embodiment of the present invention provides a circulation cooling method for a spent fuel transfer container of a million kilowatt nuclear power plant, which is used for cooling a spent fuel transfer container 10, and includes the following steps:

s1: setting a preset radiation value and a preset temperature for the inner cavity of the spent fuel transfer container 10;

s2: filling a compressed gas into the inner cavity of the spent fuel transfer container 10 until the radioactivity in the spent fuel transfer container 10 reaches a preset radioactivity value; specifically, the radioactivity is detected as the radioactivity of the air passing through the interior of the spent fuel transport container 10 and compared with a predetermined radioactivity.

S3: filling demineralized water into the spent fuel transfer container 10, and filling boron water into the spent fuel transfer container 10; the desalted water is filled into the spent fuel transfer container 10 and is injected into the spent fuel transfer container 1m³And the flow rate of the desalted water is 2m³H is used as the reference value. Specifically, a container containing demineralized water is provided, and a submersible pump is placed in the container containing demineralized water when 1m of the demineralized water is injected³The submersible pump is put into a tank filling pool filled with boron water, and the flow rate of the boron water is 5.6m³/h。

S4: and continuously filling boron water into the spent fuel transfer container 10 for circulating cooling, so that the temperature of the inner cavity is reduced to a preset temperature. Continuously using the submersible pump to fill boron water into the spent fuel transfer container 10, using the high-flow submersible pump to stir the filling tank filled with the boron water, and detecting the radioactive value of the boron water in the filling tank after running for 8 hours.

S5: if the emission value detected in step S4 satisfies the requirement, the boron water in the spent fuel transfer container 10 is discharged.

According to the circulating cooling method of the spent fuel transfer container of the million kilowatt nuclear power plant, disclosed by the embodiment of the invention, compressed gas is filled in the inner cavity of the spent fuel transfer container 10 until the radioactivity in the inner cavity reaches the preset radioactivity value; and then the spent fuel transfer container 10 is filled with demineralized water, the demineralized water can effectively avoid the crystallization of boric acid caused by overhigh temperature in the inner cavity of the spent fuel transfer container 10, the spent fuel transfer container 10 is filled with boric water through the boric water, and the boric water is continuously filled for circulating cooling, so that the inner cavity stably reaches the preset temperature, and a series of operations such as subsequent unloading and outer cover removal are facilitated.

Further, in this embodiment, as shown in fig. 1, the filling of the spent fuel transport container 10 with compressed gas specifically includes: and providing a compressed air device communicated with the spent fuel transferring container 10, wherein the compressed air device continuously blows air to the spent fuel transferring container 10 for more than 30min, and the air pressure is 0.2 MPa. Specifically, the part of the air exhausted from the inner cavity is exhausted to a pipeline of the nuclear fuel ventilation system for reprocessing after being filtered and cooled.

Further, in the present embodiment, as shown in fig. 1, a discharge cooling device 20 is provided, which is respectively communicated with the spent fuel transfer container 10 and the compressed air device, and the discharge cooling device 20 can transfer the wind of the compressed air device to the spent fuel transfer container 10. By providing the discharge cooling device 20, the temperature of the air flowing through the discharge cooling device 20 can be effectively lowered.

Further, in the present embodiment, as shown in fig. 1, a shielding filter device 30 is provided, which is communicated with the spent fuel transfer container 10 and is used for filtering the gas discharged from the spent fuel transfer container 10, and a tail end of the shielding filter device 30 is provided with a detection structure for detecting the radioactivity of the discharged gas. By providing the barrier filter device 30 and providing the barrier filter device 30 with a high efficiency filter and a pressure reducing filter valve, air can be purified and discharged under reduced pressure.

Further, in this embodiment, as shown in fig. 1, the continuous injection of the boron water at the bottom of the canning pool into the spent fuel transportation container 10 specifically includes: detecting the water temperature at the water outlet of the spent fuel transferring container 10, pausing to cool the spent fuel transferring container 10 if the temperature of the water outlet is more than 35 ℃ and less than 40 ℃, opening an inner cover bolt of the spent fuel transferring container 10 through a torque wrench, and stopping cooling if the inner cover bolt can be opened.

Further, in this embodiment, as shown in fig. 1, the continuous injection of the boron water at the bottom of the canning pool into the spent fuel transportation container 10 specifically includes: detecting the water temperature at the water outlet of the spent fuel transfer container 10, and injecting 2m into the spent fuel transfer container 10 if the water outlet temperature is higher than 40 ℃, or higher than 35 ℃ and lower than 40 ℃ but the inner cover bolt cannot be opened³And (4) cooling by continuously supplementing boron water, and stopping cooling when the water temperature at the water outlet is 35 ℃. Specifically, an ice storage tank 40 is provided, the ice storage tank 40 is communicated with the discharge cooling device 20, ice cubes are conveyed from the ice storage tank 40 to the discharge cooling device 20, then the discharge cooling device 20 transfers the ice cubes to the inner cavity of the spent fuel transfer container 10, and the spent fuel transfer container 10 is subjected to ice cube conveyingAnd (5) cooling.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.